CCOI / Cogent Communications Holdings, Inc. - Документы SEC, Годовой отчет, Доверенное заявление

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 11, 2025 Cogent Communicat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 11, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Cogent Communications Reports Second Quarter Results, Increases its Regular Quarterly Dividend on its Common Stock and Increases its Stock Buyback Program by $100.0 Million

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter Results, Increases its Regular Quarterly Dividend on its Common Stock and Increases its Stock Buyback Program by $100.0 Million Financial

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 7, 2025 Cogent Communicati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 7, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Exa

Indenture, dated as of June 17, 2025, among Cogent Communications Group, LLC, Cogent Finance, Inc., the guarantors named therein and Wilmington Trust, National Association, as trustee and collateral agent.

Exhibit 4.1 Execution Version INDENTURE Dated as of June 17, 2025 Among COGENT COMMUNICATIONS GROUP, LLC, COGENT FINANCE, INC., THE GUARANTORS PARTY HERETO and WILMINGTON TRUST, NATIONAL ASSOCIATION as Trustee and Collateral Agent 6.500% SENIOR SECURED NOTES DUE 2032 TABLE OF CONTENTS Page Article 1 DEFINITIONS AND INCORPORATION BY REFERENCE Section 1.01 Definitions 1 Section 1.02 Other Definition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 17, 2025 Cogent Communicatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 17, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 3, 2025 Cogent Communication

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 3, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Cogent Launches Notes Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. June 2, 2025 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the “Company” or “Cogent”) today announced that two of its wholly

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 2, 2025 Cogent Communication

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 2, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Ex

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported):    May 8, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Filing Fee Table

Calculation of Filing Fee Tables S-8 COGENT COMMUNICATIONS HOLDINGS, INC. Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee 1 Equity Common Stock, par value $0.001 per share Other 2,000,000 $ 55.02 $ 110,040,000.00 0.0001531 $ 16

Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter Results and Increases i

EXHIBIT 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service revenue was $247.0 mi

As filed with the Securities and Exchange Commission on May 8, 2025.

As filed with the Securities and Exchange Commission on May 8, 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 COGENT COMMUNICATIONS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 46-5706863 (State or other jurisdiction of incorporation or organizatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 7, 2025 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 7, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Amended and Restated Bylaws of Cogent Communications Holdings, Inc. (as of May 7, 2025) (filed herewith).

Exhibit 3.1 AMENDED AND RESTATED BYLAWS OF COGENT COMMUNICATIONS HOLDINGS, INC. (as of May 7, 2025) TABLE OF CONTENTS PAGE ARTICLE I. OFFICES A-1 Section 1. REGISTERED OFFICE A-1 Section 2. OTHER OFFICES A-1 ARTICLE II. MEETINGS OF STOCKHOLDERS A-1 Section 3. PLACE OF MEETINGS A-1 Section 4. NOTICE OF STOCKHOLDER BUSINESS AND NOMINATIONS A-1 Section 5. QUORUM; ADJOURNED MEETINGS AND NOTICE THEREOF

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 11, 2025 Cogent Communicati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 11, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Second Amendment to Base Indenture, dated as of April 11, 2025, by and between Cogent IPv4 LLC and Wilmington Trust, National Association.*

Exhibit 4.2 Execution Version SECOND AMENDMENT TO BASE INDENTURE SECOND AMENDMENT TO BASE INDENTURE, dated as of April 11, 2025 (this “Amendment”) to the Base Indenture, dated as of May 2, 2024, as amended by the First Amendment to Base Indenture, dated as of September 24, 2024 (the “Existing Base Indenture”; the Existing Base Indenture, as the same may be further amended, restated, supplemented o

Series 2025-1 Supplement, dated as of April 11, 2025, by and between Cogent IPv4 LLC and Wilmington Trust, National Association (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on April 11, 2025, and incorporated herein by reference).

Exhibit 4.1 Execution Version SERIES 2025-1 INDENTURE SUPPLEMENT among COGENT IPv4 LLC AND WILMINGTON TRUST, NATIONAL ASSOCIATION, AS INDENTURE TRUSTEE dated as of April 11, 2025 Secured IPv4 Revenue Notes, Series 2025-1 Class A-2 TABLE OF CONTENTS ARTICLE I DEFINITIONS AND INCORPORATION BY REFERENCE 1 Section 1.01 Definitions 1 Section 1.02 Rules of Construction 2 ARTICLE II SERIES 2025-1 NOTE DE

Cogent Announces IPv4 Address Securitization Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Announces IPv4 Address Securitization Offering WASHINGTON, D.C. April 4, 2025 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the “Company” or “Cogent”) today announced

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 4, 2025 Cogent Communicatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 4, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitt

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitt

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): March 11, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Second Amendment to Lease Agreement, dated March 11, 2025, between Sodium LLC and Cogent Communications, LLC (filed herewith).

EXHIBIT 10.3 SECOND AMENDMENT TO LEASE AGREEMENT THIS SECOND AMENDMENT TO LEASE AGREEMENT (this "Amendment") is made and entered into as of 11th day of March 2025 by and between Sodium LLC, a District of Columbia limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 2450 N Street, N.W., Washington, DC 20037 and Cogent Communicatio

Subsidiaries (filed herewith)

EXHIBIT 21.1 In Effect as of February 1, 2025 Legal Entity Jurisdiction COGENT COMMUNICATIONS HOLDINGS, INC. Delaware subsidiaries: COGENT COMMUNICATIONS GROUP, LLC Delaware COGENT COMMUNICATIONS, LLC Delaware COGENT FINANCE, INC. Delaware COGENT COMMUNICATIONS OF CALIFORNIA, INC. Delaware COGENT COMMUNICATIONS OF D.C., INC. Delaware COGENT COMMUNICATIONS OF FLORIDA, INC. Delaware COGENT COMMUNICA

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission file number 000-5

Insider Trading Compliance Policy (filed herewith).

EX-19.1 2 ccoi-20241231xex19d1.htm EX-19.1 Exhibit 19.1 Cogent Communications Holdings, Inc. Insider Trading Compliance Policy Cogent Communications Holdings, Inc. (the “Company”) seeks to promote a culture that encourages ethical conduct and a commitment to compliance with the law. We require our personnel to comply at all times with federal law governing insider trading. This policy sets forth p

Cogent Communications Reports Fourth Quarter and Full Year 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service r

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 27, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 9, 2025 Cogent Communicat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 9, 2025 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Amendment No. 10 to Employment Agreement of David Schaeffer, dated as of January 14 2025 (previously filed as Exhibit 10.1 to our Current Report on Form 8 - K, filed on January 15, 2025, and incorporated herein by reference).

EXHIBIT 10.1 Amendment No. 10 to Employment Agreement of David Schaeffer This amendment (“Amendment”) is made by and among Cogent Communications Holdings, Inc. (“Holdings”), Cogent Communications, LLC (the “Company”) and David Schaeffer (“Executive”). This Amendment amends the Employment Agreement between the Company and Executive dated February 7, 2000 as amended. 1. The second and third sentence

Form of 2025 Restricted Stock Award between the Company and David Schaeffer (previously filed as Exhibit 10.2 to our Current Report on Form 8 - K, filed on January 15, 2025, and incorporated herein by reference).

Exhibit 10.2 RESTRICTED STOCK AWARD Name:  Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: [] 2017 Incentive Award Plan (the “Plan”)   1.                  Grant: Effective as of the Grant Date specified above you have been granted [] ([]) Shares (“Time Vesting Shares”) and up to [] ([]) performance-vesting Shares of (the “Performance Vesting Shares” and along with the Time Vesting

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 7, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

Cogent Communications Reports Third Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Third Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service revenue was $260

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 8, 2024 Cogent Communicati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 8, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Communications Reports Second Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service revenue was $23

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Exa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 11, 2024 Cogent Communicatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 11, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Indenture, dated as of June 11, 2024 among Cogent Communications Group, LLC, Cogent Finance Inc., the guarantors named therein and Wilmington Trust National Association as trustee (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on June 11, 2024, and incorporated herein by reference).

Exhibit 4.1 Execution Version INDENTURE Dated as of June 11, 2024 Among COGENT COMMUNICATIONS GROUP, LLC, COGENT FINANCE, INC., THE GUARANTORS PARTY HERETO and WILMINGTON TRUST, NATIONAL ASSOCIATION as Trustee 7.000% SENIOR NOTES DUE 2027 TABLE OF CONTENTS Page Article 1 DEFINITIONS AND INCORPORATION BY REFERENCE Section 1.01 Definitions 1 Section 1.02 Other Definitions 30 Section 1.03 Rules of Co

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 6, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation) (

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 5, 2024 Cogent Communication

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 5, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Cogent Launches Notes Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. June 5, 2024 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the “Company” or “Cogent”) today announced that two of its wholly

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 9, 2024 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 9, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Cogent Communications Reports First Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson  John Chang + 1 (202) 295-4299  + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter 2024 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service revenue for Q1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Ex

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 8, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Series 2024-1 Supplement, dated as of May 2, 2024, by and between Cogent IPv4 LLC and Wilmington Trust, National Association, (previously filed as Exhibit 4.2 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference)

Exhibit 4.2 EXECUTION VERSION SERIES 2024-1 INDENTURE SUPPLEMENT between COGENT IPV4 LLC AND WILMINGTON TRUST, NATIONAL ASSOCIATION, AS INDENTURE TRUSTEE dated as of May 2, 2024 Secured IPv4 Revenue Notes, Series 2024-1 Class A-2 TABLE OF CONTENTS ARTICLE I DEFINITIONS AND INCORPORATION BY REFERENCE 1 Section 1.01 Definitions 1 Section 1.02 Rules of Construction 2 ARTICLE II SERIES 2024-1 NOTE DET

Second Supplemental Indenture, dated as of May 3, 2024, by and among Cogent Communications Group, LLC, Cogent Finance, Inc. and Wilmington Trust, National Association, as trustee and collateral agent (previously filed as Exhibit 4.5 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference).

Exhibit 4.5 Execution Version SECOND SUPPLEMENTAL INDENTURE SECOND SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of May 3, 2024 among Cogent Finance, Inc., a Delaware corporation, (the “Co-Issuer”), Cogent Communications Group, LLC, a Delaware limited liability company (f/k/a Cogent Communications Group, Inc., a Delaware corporation) (the “Company”), and Wilmington Trust, Nation

Second Supplemental Indenture, dated as of May 3, 2024, by and among Cogent Communications Group, LLC, Cogent Finance, Inc. and Wilmington Trust, National Association, as trustee (previously filed as Exhibit 4.6 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference).

Exhibit 4.6 Execution Version SECOND SUPPLEMENTAL INDENTURE SECOND SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of May 3, 2024, among Cogent Finance, Inc., a Delaware corporation, (the “Co-Issuer”), Cogent Communications Group, LLC, a Delaware limited liability company (f/k/a Cogent Communications Group, Inc., a Delaware corporation) (the “Company”), and Wilmington Trust, Natio

First Supplemental Indenture, dated as of May 2, 2024, by and among Cogent Communications Group, LLC, Sprint Solutions Wireline LLC and Wilmington Trust, National Association, as trustee and collateral agent (previously filed as Exhibit 4.3 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference).

Exhibit 4.3 Execution Version FIRST SUPPLEMENTAL INDENTURE First Supplemental Indenture (this “Supplemental Indenture”), dated as of May 2, 2024, among Sprint Solutions Wireline LLC (the “Guaranteeing Subsidiary”), a subsidiary of Cogent Communications Group, LLC, a Delaware limited liability company (the “Company”), and Wilmington Trust, National Association, a national banking association organi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 2, 2024 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 2, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Base Indenture, dated as of May 2, 2024, by and between Cogent IPv4 LLC and Wilmington Trust, National Association (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference).

Exhibit 4.1 EXECUTION VERSION BASE INDENTURE between COGENT IPV4 LLC, as the Issuer, and Wilmington Trust, National Association, as the Indenture Trustee dated as of May 2, 2024 Secured IPv4 Address Revenue Notes Table of Contents Page ARTICLE I DEFINITIONS AND INCORPORATION BY REFERENCE 1 Section 1.01. Definitions 1 Section 1.02. Rules of Construction 37 ARTICLE II THE NOTES 38 Section 2.01. The

First Supplemental Indenture, dated as of May 2, 2024, by and among Cogent Communications Group, LLC, Sprint Solutions Wireline LLC and Wilmington Trust, National Association, as trustee (previously filed as Exhibit 4.4 to our Current Report on Form 8-K, filed on May 6, 2024, and incorporated herein by reference).

Exhibit 4.4 Execution Version FIRST SUPPLEMENTAL INDENTURE First Supplemental Indenture (this “Supplemental Indenture”), dated as of May 2, 2024, among Sprint Solutions Wireline LLC (the “Guaranteeing Subsidiary”), a subsidiary of Cogent Communications Group, LLC, a Delaware limited liability company (the “Company”), and Wilmington Trust, National Association, a national banking association organi

Cogent Announces IPv4 Address Securitization Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Announces IPv4 Address Securitization Offering WASHINGTON, D.C. April 25, 2024 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the “Company” or “Cogent”) yesterday anno

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 25, 2024 Cogent Communicati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 25, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 19, 2024 Cogent Communicati

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 19, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e

Form of Restricted Stock Award between the Company and the Vice President named executive officers (Retention) (filed herewith).

EXHIBIT 10.23 RESTRICTED STOCK AWARD Name: Cogent Communications Holdings, Inc. Grant Date: January 3, 2024 2017 Incentive Award Plan (the “Plan”) 1.Grant: Effective as of the Grant Date specified above you have been granted [] ([] thousand) Shares (the “Restricted Shares”) of Cogent Communications Holdings, Inc. (the “Company”) subject to the vesting requirement described below. 2.Normal Vesting:

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission file number 000-5

Cogent Communications Reports Fourth Quarter and Full Year 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: Jocelyn Johnson + 1 (202) 295-4299 [email protected] For Investor Relations: John Chang + 1 (202) 295-4212 [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · The gain

Policy for Recovery of Erroneously Awarded Compensation (filed herewith)

EXHIBIT 97.1 COGENT COMMUNICATIONS HOLDINGS, INC. POLICY FOR RECOVERY OF ERRONEOUSLY AWARDED COMPENSATION Cogent Communications Holdings, Inc. (the “Company”) has adopted this Policy for Recovery of Erroneously Awarded Compensation (the “Policy”), effective as of October 2, 2023 (the “Effective Date”). Capitalized terms used in this Policy but not otherwise defined herein are defined in Section 11

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 29, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

Subsidiaries (filed herewith)

In Effect as of February 7, 2024 EXHIBIT 21.1 Legal Entity Jurisdiction COGENT COMMUNICATIONS HOLDINGS, INC. Delaware subsidiaries: COGENT COMMUNICATIONS GROUP, INC. Delaware COGENT COMMUNICATIONS, INC. Delaware COGENT COMMUNICATIONS OF CALIFORNIA, INC. Delaware COGENT COMMUNICATIONS OF D.C., INC. Delaware COGENT COMMUNICATIONS OF FLORIDA, INC. Delaware COGENT COMMUNICATIONS OF MARYLAND, INC. Dela

CCOI / Cogent Communications Holdings, Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0638-cogentcommunicationsh.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 16)* Name of issuer: Cogent Communications Holdings Inc Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the approp

CCOI / Cogent Communications Holdings, Inc. / VAUGHAN NELSON INVESTMENT MANAGEMENT, L.P. - AMENDMENT NO. 1 TO SCHEDULE 13G Passive Investment

SC 13G/A 1 vaughannelsonccoi13g4q2022.htm AMENDMENT NO. 1 TO SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) Under the Securities Exchange Act of 1934 (Amendment No. 1) Cogent Communications Holdings, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 19239V302 (CUSIP Number) December 31, 2023 (Date of Event which Requ

Form of Restricted Stock Award between the Company and David Schaeffer (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on January 5, 2024, and incorporated herein by reference).

Exhibit 10.2 RESTRICTED STOCK AWARD Name: Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: [] 2017 Incentive Award Plan (the “Plan”) 1. Grant: Effective as of the Grant Date specified above you have been granted [] ([]) Shares (“Time Vesting Shares”) and up to [] ([]) performance-vesting Shares of (the “Performance Vesting Shares” and along with the Time Vesting Shares the “Restrict

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 3, 2024 Cogent Communicat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 3, 2024 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Amendment No. 9 to Employment Agreement of David Schaeffer, dated as of January 3, 2024 (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on January 5, 2024, and incorporated herein by reference).

Exhibit 10.1 Amendment No. 9 to Employment Agreement of David Schaeffer This amendment is made by and among Cogent Communications Holdings, Inc. (“Holdings”), Cogent Communications, Inc. (the “Company”) and David Schaeffer (“Executive”). This amendment amends the employment agreement between the Company and Executive dated February 7, 2000 as amended. 1. The second and third sentences of Section 2

Cogent Communications Reports Third Quarter 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Third Quarter 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Service revenue increase

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period Ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 9, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 28, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Cogent Communications Reports Second Quarter 2023 Results Including the Sprint Wireline Business, Records a $1.2 Billion Gain on Bargain Purchase, Records Basic Earnings per Share of $23.84 and Increases its Regular Quarterly Dividend on its Common S

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter 2023 Results Including the Sprint Wireline Business, Records a $1.2 Billion Gain on Bargain Purchase, Records Basic Earnings per Share of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 10, 2023 Cogent Communicat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 10, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Cogent Communications Reports Second Quarter 2023 Results Including the Sprint Wireline Business, Records a $1.2 Billion Gain on Bargain Purchase, Records Basic Earnings per Share of $23.84 and Increases its Regular Quarterly Dividend on its Common S

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter 2023 Results Including the Sprint Wireline Business, Records a $1.2 Billion Gain on Bargain Purchase, Records Basic Earnings per Share of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No.1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 10, 202

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No.1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 10, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdicti

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Exa

First Amendment to Lease Agreement, dated February 20, 2023, between Germanium LLC and Cogent Communications, Inc., for early access to technical space at 196 Van Buren Street, Herndon, VA. (previously filed as Exhibit 10.6 to our Quarterly Report on Form 10-Q, filed on August 9, 2023, and incorporated herein by reference)

EXHIBIT 10.6 FIRST AMENDMENT TO LEASE AGREEMENT THIS FIRST AMENDMENT TO LEASE AGREEMENT (this "Amendment") is made and entered into as of 20th day of February 2023 by and between Germanium LLC, a Delaware limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 1627 K Street, NW, Washington, D.C. 20006 and Cogent Communications, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 25, 2023 Cogent Communicatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 25, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Second Amendment to Lease Agreement, dated July 25, 2023, between Germanium LLC and Cogent Communications, Inc., for technical space at 196 Van Buren Street, Herndon, VA (filed as Exhibit 10.1 to our periodic report on Form 8-K dated July 27, 2023 and incorporated herein by reference).

EXHIBIT 10.1 SECOND AMENDMENT TO LEASE AGREEMENT THIS SECOND AMENDMENT TO LEASE AGREEMENT (this "Amendment") is made and entered into as of 25th day of July 2023 by and between Germanium LLC, a Delaware limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 1627 K Street, NW, Washington, D.C. 20006 and Cogent Communications, Inc. a

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

Exhibit 99.2 UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION Acquisition of the Wireline Business of Sprint Communications On September 6, 2022, Cogent Infrastructure, Inc., a Delaware corporation (the “Buyer”) and a direct wholly owned subsidiary of Cogent Communications Holdings, Inc., a Delaware corporation (the “Company”), entered into a Membership Interest Purchase Agreement (the

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 17, 2023

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): July 17, 2023 (May 1, 2023) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or oth

Wireline Business (A Carve-out Business of T-Mobile US, Inc.) Combined Financial Statements and Independent Auditor's Report As of and for the years ended December 31, 2022 and 2021 Wireline Business (A Carve-out Business of T-Mobile US, Inc.) Index

Exhibit 99.1 Wireline Business (A Carve-out Business of T-Mobile US, Inc.) Combined Financial Statements and Independent Auditor's Report As of and for the years ended December 31, 2022 and 2021 Wireline Business (A Carve-out Business of T-Mobile US, Inc.) Index to the Combined Financial Statements Page No. Independent Auditor's Report 1 Combined Financial Statements Combined Balance Sheets 3 Comb

As filed with the Securities and Exchange Commission on May 12, 2023.

As filed with the Securities and Exchange Commission on May 12, 2023. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 COGENT COMMUNICATIONS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 46-5706863 (State or other jurisdiction of incorporation or organizati

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Cogent Communications Holdings, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Ex

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 3, 2023 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 3, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Restricted Stock Award, dated as of May 3, 2023, between the Company and Greg W. O’Connor (filed herewith).

EXHIBIT 10.1 RESTRICTED STOCK AWARD Name: Greg W. O’Connor Cogent Communications Holdings, Inc. Grant Date: May 3, 2023 2017 Incentive Award Plan (the “Plan”) 1. Grant: Effective as of the Grant Date specified above you have been granted 16,000 (sixteen thousand) Shares (the “Restricted Shares”) of Cogent Communications Holdings, Inc. (the “Company”) subject to the vesting requirement described be

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 4, 2023 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 4, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Cogent Communications Closes its Acquisition of the Sprint Wireline Business, Reports First Quarter 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Closes its Acquisition of the Sprint Wireline Business, Reports First Quarter 2023 Results and Increases its Regular Quarterly Dividend on its Common Stock Fina

Customer Subscriber Agreement, dated as of May 1, 2023, by and between Cogent Infrastructure, Inc. and T-Mobile USA, Inc. (previously filed as Exhibit 10.3 to our Current Report on Form 8-K, filed on May 1, 2023, and incorporated herein by reference).

Exhibit 10.3 [***] Certain information in this document has been excluded pursuant to Regulation S-K, Item (601)(b)(10). Such excluded information is not material and is the type that the registrant treats as private or confidential. Customer Subscriber Agreement (Network Services Terms & Conditions) Global This Customer Subscriber Agreement (“CSA”), together with any general terms and conditions,

Transition Services Agreement, dated as of May 1, 2023, by and between Cogent Infrastructure, Inc. and Sprint LLC (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on May 1, 2023, and incorporated herein by reference).

  Exhibit 10.1   [***] Certain information in this document has been excluded pursuant to Regulation S-K, Item (601)(b)(10). Such excluded information is not material and is the type that the registrant treats as private or confidential.   TRANSITION SERVICES AGREEMENT   This TRANSITION SERVICES AGREEMENT (this “Agreement”) is made and entered into as of May 1, 2023 (the “Closing Date”), by and be

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 1, 2023 Cogent Communications

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 1, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Cogent Communications Announces Closing of Acquisition of T-Mobile’s Wireline Business

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Announces Closing of Acquisition of T-Mobile’s Wireline Business WASHINGTON, D.C. May 1, 2023 – Cogent Communications Holdings, Inc. (“Cogent”) (NASDAQ: CCOI) t

IP Transit Agreement, dated as of May 1, 2023, by and between Cogent Communications, Inc. and T-Mobile USA, Inc. (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on May 1, 2023, and incorporated herein by reference).

Exhibit 10.2 [***] Certain information in this document has been excluded pursuant to Regulation S-K, Item (601)(b)(10). Such excluded information is not material and is the type that the registrant treats as private or confidential. Network Services Terms & Conditions North America 1. Services and Term. 1.1. Pursuant to the CSA, Cogent will provide the Services ordered by Customer each month up t

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e

Henry Kilmer Severance Agreement with Cogent Communications, Inc., dated March 13, 2012 (previously filed as Exhibit 10.27 to our Annual Report on Form 10-K filed on February 24, 2023, and incorporated herein by reference).

Exhibit 10.27 Severance Agreement 1.This agreement is entered into by Cogent Communications, Inc. (“Cogent”) and the executive employee signing this Agreement, below (“Executive”). 2.As an inducement for Executive to focus his or her full efforts on Cogent’s business without undue concern for future employment the Compensation Committee of the Cogent Board of Directors has approved the following m

Subsidiaries (filed herewith)

In Effect as of February 1, 2023 EXHIBIT 21.1 Legal Entity Jurisdiction COGENT COMMUNICATIONS HOLDINGS, INC. (Delaware) subsidiaries: COGENT COMMUNICATIONS GROUP, INC. (Delaware) COGENT COMMUNICATIONS, INC. (Delaware) COGENT INFRASTRUCTURE, INC. (Delaware) COGENT COMMUNICATIONS OF CALIFORNIA, INC. (Delaware) COGENT AFRICAONE, LLC (Delaware) COGENT AFRICATWO, LLC (Delaware) COGENT IH, LLC (Delaware

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission file number 000-5

Cogent Communications Reports Fourth Quarter and Full Year 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights · Cogent ap

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 23, 2023 Cogent Communic

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 23, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

CCOI / Cogent Communications Holdings Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0612-cogentcommunicationsh.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 15)* Name of issuer: Cogent Communications Holdings Inc. Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 30, 2022 Check the appro

CCOI / Cogent Communications Holdings Inc / VAUGHAN NELSON INVESTMENT MANAGEMENT, L.P. - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) Under the Securities Exchange Act of 1934 (Amendment No. ) Cogent Communications Holdings, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 19239V302 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the r

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 6, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

Lease Agreement (office space), dated January 6, 2023, between Thorium LLC and Cogent Communications, Inc. for offices at 198 Van Buren Street, Herndon, VA (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on January 11, 2023 and incorporated herein by reference).

Exhibit 10.1 LEASE AGREEMENT 198 Van Buren Street Herndon, Virginia THIS LEASE AGREEMENT (hereinafter referred to as this "Lease") dated January 6, 2023, is made and entered into by and between Thorium LLC, a Delaware limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 1627 K Street, NW, Washington, D.C. 20006 and Cogent Communi

Lease Agreement (network operations), dated January 6, 2023, between Germanium LLC and Cogent Communications, Inc. for technical space at 196 Van Buren Street, Herndon, VA (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on January 11, 2023 and incorporated herein by reference).

Exhibit 10.2 LEASE AGREEMENT 196 Van Buren Street Herndon, Virginia THIS LEASE AGREEMENT (hereinafter referred to as this "Lease") dated January 6, 2023, is made and entered into by and between Germanium LLC, a Delaware limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 1627 K Street, NW, Washington, D.C. 20006 and Cogent Commu

Restricted Stock Award, dated as of January 3, 2023, between the Company and David Schaeffer (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on January 6, 2023, and incorporated herein by reference).

Exhibit 10.1 RESTRICTED STOCK AWARD Name: Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: January 3, 2023 2017 Incentive Award Plan (the ?Plan?) 1. Grant: Effective as of the Grant Date specified above you have been granted 72,000 (seventy two thousand) Shares (?Time Vesting Shares?) and up to 88,000 (eighty eight thousand) performance-vesting Shares of (the ?Performance Vesting Sh

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 3, 2023 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 3, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

Cogent Communications Reports Third Quarter 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Third Quarter 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock Financial and Business Highlights ? Cogent approved an incre

Guaranty, dated as of September 6, 2022, by and between Cogent Communications Holdings, Inc. and Sprint LLC (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on September 7, 2022 and incorporated herein by reference).

Exhibit 10.1 Execution Version GUARANTY This GUARANTY (this ?Guaranty?) is dated as of September 6, 2022, by Cogent Communications Holdings, Inc., a Delaware corporation (hereinafter ?Guarantor?), as the direct parent company of Cogent Infrastructure, Inc., a Delaware corporation (hereinafter ?Buyer?), in favor of Sprint LLC, a Delaware limited liability company (hereinafter ?Seller?). Capitalized

Cogent Announces Definitive Agreement to Acquire T-Mobile’s Wireline Business

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Announces Definitive Agreement to Acquire T-Mobile?s Wireline Business WASHINGTON, D.C. September 7, 2022 ? Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (?Cogent?) anno

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 7, 2022 (September 6, 2022) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdi

Membership Interest Purchase Agreement, dated as of September 6, 2022, by and among Cogent Infrastructure, Inc., Sprint LLC and Sprint Communications LLC (previously filed as Exhibit 2.1 to our Current Report on Form 8-K, filed on September 7, 2022 and incorporated herein by reference). *

Exhibit 2.1 MEMBERSHIP INTEREST PURCHASE AGREEMENT by and among Sprint LLC, Sprint Communications LLC and Cogent Infrastructure, Inc. Dated as of September 6, 2022 TABLE OF CONTENTS Page Article 1 DEFINITIONS 2 Article 2 SALE AND PURCHASE OF MEMBERSHIP INTERESTS 16 2.1 Agreement to Sell and Purchase 16 2.2 Purchase Price; Closing Payments 16 2.3 Purchase Price Adjustment 17 2.4 Purchase Price Allo

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 24, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdictio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 4, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Communications Reports Second Quarter 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter 2022 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights ? Cogent approv

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 27, 2022 (June 24, 2022) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 22, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Indenture related to the 7.000% Senior Notes due 2027, dated as of June 22, 2022, among Cogent Communications Group, Inc., the guarantors named therein, and Wilmington Trust, National Association, as trustee and collateral agent (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on June 22, 2022 and incorporated herein by reference).

Exhibit 4.1 Execution Version INDENTURE Dated as of June 22, 2022 Among COGENT COMMUNICATIONS GROUP, INC. THE GUARANTORS PARTY HERETO and WILMINGTON TRUST, NATIONAL ASSOCIATION as Trustee 7.000% SENIOR NOTES DUE 2027 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE Section 1.01 Definitions 1 Section 1.02 Other Definitions 30 Section 1.03 Rules of Construction 30 Section

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 7, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation) (

Cogent Launches Notes Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. June 6, 2022 ? Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the ?Company?) today announced that Cogent Communications Group, I

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 6, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Restricted Stock Award, dated as of May 4, 2022, between the Company and Thaddeus G. Weed (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on May 5, 2022 and incorporated herein by reference).

EXHIBIT 10.1 RESTRICTED STOCK AWARD Name:??Tad Weed Cogent Communications Holdings, Inc. Grant Date: May 4, 2022 2017 Incentive Award Plan (the ?Plan?) 1.????????????Grant: Effective as of the Grant Date specified above you have been granted 10,000 (ten thousand) Shares (the ?Restricted Shares?) of Cogent Communications Holdings, Inc. (the ?Company?) subject to the vesting requirement described be

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 5, 2022 (May 4, 2022) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of inc

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Dark Fiber IRU Agreement, dated April 14, 2000, between WilTel Communications, Inc. and Cogent Communications, Inc., as amended June 27, 2000, December 11, 2000, January 26, 2001, and February 21, 2001, filed as Exhibit 10.1 to our periodic report on Form 10-Q filed on May 5, 2022 and incorporated herein by reference. **

Exhibit 10.1 Certain information contained in this document, marked by brackets, has been omitted because it is both (i) not material and (ii) is the type that the registrant treats as private or confidential. ? DARK FIBER IRU AGREEMENT Between WILLIAMS COMMUNICATIONS, INC. (?Williams?) and COGENT COMMUNICATIONS, INC. (?Cogent?) Dated: April 14, 2000 ? ? TABLE OF CONTENTS ? ? ? ARTICLE Page ARTICL

Amended and Restated Bylaws of Cogent Communications Holdings, Inc. (as of May 4, 2022) (previously filed as Exhibit 3.1 to our Current Report on Form 8-K filed on May 4, 2022 and incorporated herein by reference).

EXHIBIT 3.1 AMENDED AND RESTATED BYLAWS OF COGENT COMMUNICATIONS HOLDINGS, INC. (as of May 4, 2022) TABLE OF CONTENTS PAGE ARTICLE I. OFFICES 1 Section 1. REGISTERED OFFICE 1 Section 2. OTHER OFFICES 1 ARTICLE II. MEETINGS OF STOCKHOLDERS 1 Section 3. PLACE OF MEETINGS 1 Section 4. NOTICE OF STOCKHOLDER BUSINESS AND NOMINATIONS 1 Section 5. QUORUM; ADJOURNED MEETINGS AND NOTICE THEREOF 3 Section 6

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 4, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 29, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 29, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Communications Reports First Quarter 2022 Results, Increases its Regular Quarterly Dividend on its Common Stock by $0.025 and Appoints CFO

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter 2022 Results, Increases its Regular Quarterly Dividend on its Common Stock by $0.025 and Appoints CFO Financial and Business Highlights ?

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

DEF 14A 1 tm223411-2def14a.htm DEF 14A TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.  )

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549? SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ?) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? ? Confidential, for Use of the Commission Only (as perm

Subsidiaries (filed herewith)

In Effect as of February 1, 2022 EXHIBIT 21.1 ? Legal Entity Jurisdiction ? ? COGENT COMMUNICATIONS HOLDINGS, INC. (Delaware) subsidiaries: ? COGENT COMMUNICATIONS GROUP, INC. (Delaware) COGENT COMMUNICATIONS, INC. (Delaware) COGENT COMMUNICATIONS OF CALIFORNIA, INC. (Delaware) COGENT AFRICAONE, LLC (Delaware) COGENT AFRICATWO, LLC (Delaware) COGENT IH, LLC (Delaware) COGENT WG, LLC (Delaware) COG

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K

Table of Contents ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Raymond B. “Brad” Kummer Severance Agreement with Cogent Communications, Inc., dated September 25, 2003 (filed herewith).

Exhibit 10.27 ? Severance Agreement 1.This agreement is entered into by Cogent Communications, Inc. (?Cogent?) and the executive employee signing this Agreement, below (?Executive?). 2.As an inducement for Executive to focus his or her full efforts on Cogent?s business without undue concern for future employment the Compensation Committee of the Cogent Board of Directors has approved the following

Raymond B. “Brad” Kummer Severance Agreement with Cogent Communications, Inc., dated September 25, 2003 (previously filed as Exhibit 10.26 to our Annual Report on Form 10-K filed on February 25, 2022, and incorporated herein by reference).

Exhibit 10.26 ? Severance Agreement 1.This agreement is entered into by Cogent Communications, Inc. (?Cogent?) and the executive employee signing this Agreement, below (?Executive?). 2.As an inducement for Executive to focus his or her full efforts on Cogent?s business without undue concern for future employment the Compensation Committee of the Cogent Board of Directors has approved the following

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 24, 2022 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

Cogent Communications Reports Fourth Quarter and Full Year 2021 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2021 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights

CCOI / Cogent Communications Holdings Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 14)* Name of issuer: Cogent Communications Holdings Inc. Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 31, 2021 Check the appropriate box to designate the rule pursuant to which this Sch

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): January 5, 2022 (January 3, 2022) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdictio

Restricted Stock Award, dated as of January 3, 2022, between the Company and David Schaeffer (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on January 5, 2022, and incorporated herein by reference).

Exhibit 10.1 RESTRICTED STOCK AWARD Name: Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: January 3, 2022 2017 Incentive Award Plan (the ?Plan?) 1. Grant: Effective as of the Grant Date specified above you have been granted 72,000 (seventy two thousand) Shares (?Time Vesting Shares?) and up to 88,000 (eighty eight thousand) performance-vesting Shares of (the ?Performance Vesting Sh

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): December 23, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporati

Cogent Communications Reports Third Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Third Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights ? Cogent approved a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 4, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

Cogent Communications Reports Second Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Second Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights ? Cogent approved

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 5, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q

Table of Contents ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 4, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 11, 2021 (May 7, 2021) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of in

Indenture related to the 3.500% Senior Secured Notes due 2026, dated as of May 7, 2021, among Cogent Communications Group, Inc., the guarantors named therein, and Wilmington Trust, National Association, as trustee and collateral agent (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on May 11, 2021 and incorporated herein by reference).

Exhibit 4.1 Execution Version INDENTURE Dated as of May 7, 2021 Among COGENT COMMUNICATIONS GROUP, INC. THE GUARANTORS PARTY HERETO and WILMINGTON TRUST, NATIONAL ASSOCIATION as Trustee and Collateral Agent 3.500% SENIOR SECURED NOTES DUE 2026 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE Section 1.01 Definitions 1 Section 1.02 Other Definitions 32 Section 1.03 Rules

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 13)*

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 13)* Name of issuer: Cogent Communications Holdings Inc. Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: April 30, 2021 Check the appropriate box to designate the rule pursuant to which this Schedu

- FORM S-8

As filed with the Securities and Exchange Commission on May 3, 2021. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 COGENT COMMUNICATIONS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 46-5706863 (State or other jurisdiction of incorporation or organizatio

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 30, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 29, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 29, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Launches Notes Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson + 1 (202) 295-4212 + 1 (202) 295-4299 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. April 29, 2021 ? Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (the Company?) today announced that Cogent Communications Group, Inc. (?Coge

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 28, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 28, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Date Change for Cogent Communications Earnings Release

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace +1(202)295-4299 +1(202)295-4202 [email protected] [email protected] Date Change for Cogent Communications Earnings Release WASHINGTON, D.C. April 28, 2021 ? Cogent Communications Holdings, Inc. (?Cogent?) (NASDAQ: CCOI) today announced that its press rel

Cogent Communications Reports First Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports First Quarter Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights ? Cogent approved a

Quarterly Report - FORM 10-Q

Table of Contents ? ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

- DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

- DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.) Filed by the Registrant x Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): April 6, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation)

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): March 26, 2021 (March 23, 2021) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction

Cogent Communications Reports Fourth Quarter and Full Year 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 25, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdi

Amended and Restated Cogent Communications Holdings, Inc. 2017 Incentive Award Plan (previously filed as Appendix A of our Definitive Proxy Statement on Schedule 14A filed March 5, 2021 and incorporated herein by reference).

? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ??) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? ? Confidential, for Use of the Commission Only (as permitted by Rule 14

Subsidiaries (filed herewith)

? ? In Effect as of February 1, 2021 EXHIBIT 21.1 ? ? ? Legal Entity Jurisdiction ? ? COGENT COMMUNICATIONS HOLDINGS, INC. (Delaware) subsidiaries: ? COGENT COMMUNICATIONS GROUP, INC. (Delaware) COGENT COMMUNICATIONS, INC. (Delaware) COGENT COMMUNICATIONS OF CALIFORNIA, INC. (Delaware) COGENT AFRICAONE, LLC (Delaware) COGENT AFRICATWO, LLC (Delaware) COGENT IH, LLC (Delaware) COGENT WG, LLC (Delaw

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 26, 2021 (February 24, 2021) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdi

Restricted Stock Award, dated as of February 24, 2021, between the Company and David Schaeffer (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on February 26, 2021, and incorporated herein by reference).

Exhibit 10.1 RESTRICTED STOCK AWARD Name: Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: February 24, 2021 2017 Incentive Award Plan (the ?Plan?) 1. Grant: Effective as of the Grant Date specified above you have been granted 84,000 (eighty-four thousand) Shares (?Time Vesting Shares?) and up to 105,000 (one hundred five thousand) performance-vesting Shares of (the ?Performance Ves

Annual Report - 10-K

Table of Contents ? ? ? UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 25, 2021 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

Cogent Communications Reports Fourth Quarter and Full Year 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

EX-99.1 2 tm217664d1ex99-1.htm EXHIBIT 99.1 Exhibit 99.1 For Immediate Release Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 12)*

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 12)* Name of issuer: Cogent Communications Holdings Inc. Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 31, 2020 Check the appropriate box to designate the rule pursuant to which this Sch

Financial Statements and Exhibits, Results of Operations and Financial Condition - FORM 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 5, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC.

Cogent Communications Reports Third Quarter 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Third Quarter 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights · Cogent appro

Cogent Communications Reports Second Quarter 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson Sean Wallace + 1 (202) 295-4299 + 1 (202) 295-4202 [email protected] [email protected] Cogent Communications Reports Second Quarter 2020 Results and Increases its Regular Quarterly Dividend on its Common Stock by $0.025 Financial and Business Highlights · Cogent appr

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Exa

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 6, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 10, 2020 (June 9, 2020) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of

First Supplemental Indenture to the Base Indenture, dated as of June 10, 2020, among Cogent Communications Group, Inc., the guarantors named therein and Wilmington Trust, National Association, as trustee (previously filed as Exhibit 4.4 to our Current Report on Form 8-K, filed on June 10, 2020, and incorporated herein by reference).

Exhibit 4.4 FIRST SUPPLEMENTAL INDENTURE Dated as of June 10, 2020 Among COGENT COMMUNICATIONS GROUP, INC. the Guarantors party hereto and WILMINGTON TRUST, NATIONAL ASSOCIATION, as Trustee 4.375% SENIOR NOTES DUE 2024 FIRST SUPPLEMENTAL INDENTURE, dated as of June 10, 2020 (this “Supplemental Indenture”), among COGENT COMMUNICATIONS GROUP, INC. (the “Company”), as issuer, the guarantors party her

First Supplemental Indenture to the Temporary Indenture, dated as of June 10, 2020, between Cogent Communications Group, Inc. and Wilmington Trust, National Association, as trustee (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on June 10, 2020, and incorporated herein by reference).

Exhibit 4.1 FIRST SUPPLEMENTAL INDENTURE Dated as of June 10, 2020 Between COGENT COMMUNICATIONS GROUP, INC. and WILMINGTON TRUST, NATIONAL ASSOCIATION, as Trustee 4.375% SENIOR NOTES DUE 2024 FIRST SUPPLEMENTAL INDENTURE, dated as of June 10, 2020 (this “Supplemental Indenture”), between COGENT COMMUNICATIONS GROUP, INC. (as successor by merger to Cogent Communications Finance, Inc.) (the “Compan

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 9, 2020 (June 3, 2020) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of i

Indenture related to the 4.375% Senior Notes due 2024, dated as of June 3, 2020, among Cogent Communications Finance, Inc., Wilmington Trust, National Association, as trustee, Deutsche Bank AG, London Branch, as paying agent, and Deutsche Bank Trust Company Americas, as authentication agent and registrar (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on June 9, 2020, and incorporated herein by reference).

Exhibit 4.1 Execution Version INDENTURE Dated as of June 3, 2020 Among COGENT COMMUNICATIONS FINANCE, INC., WILMINGTON TRUST, NATIONAL ASSOCIATION, as Trustee, DEUTSCHE BANK AG, LONDON BRANCH, as Paying Agent, and DEUTSCHE BANK TRUST COMPANY AMERICAS, as Registrar and Authentication Agent 4.375% SENIOR NOTES DUE 2024 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE Secti

Cogent Launches Notes Offering

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson + 1 (202) 295-4212 + 1 (202) 295-4299 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. May 19, 2020 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (“Cogent Communications”) today announced that Cogent Communications Finance,

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 19, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 19, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Severance Agreement, dated May 11, 2020, between the Company and Sean Wallace (previously filed as Exhibit 10.3 to our Current Report on Form 8-K, filed on May 11, 2020, and incorporated herein by reference).

Exhibit 10.3 Severance Agreement 1. This agreement is entered into by Cogent Communications, Inc. (“Cogent”) and the executive employee signing this Agreement, below (“Executive”). 2. As an inducement for Executive to focus his or her full efforts on Cogent’s business without undue concern for future employment the Compensation Committee of the Cogent Board of Directors has approved the following

Employment Letter between the Company and Sean Wallace, effective April 22, 2020 (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on May 11, 2020, and incorporated herein by reference).

Exhibit 10.1 2450 N Street, NW Washington, DC 20037 Tel: 202-295-4200 Confidential Fax: [private line] April 17, 2020 Mr. Sean Wallace [private address] Dear Sean: Cogent Communications is offering you the position of Vice President, Chief Financial Officer and Treasurer. Your monthly starting salary will be $29,167, the equivalent of $350,000.00 if calculated annually. Your position will be locat

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 11, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (

Restricted Stock Award, dated May 11, 2020, between the Company and Sean Wallace (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on May 11, 2020, and incorporated herein by reference).

Exhibit 10.2 RESTRICTED STOCK AWARD Name: Sean Wallace Cogent Communications Holdings, Inc. Grant Date: May 11, 2020 2017 Incentive Award Plan (the “Plan”) 1. Grant: Effective as of the Grant Date specified above you have been granted 12,000 (twelve thousand) Shares (the “Restricted Shares”) of Cogent Communications Holdings, Inc. (the “Company”) subject to the vesting requirement described below.

Sean Wallace Named Chief Financial Officer of Cogent Communications

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Sean Wallace Named Chief Financial Officer of Cogent Communications [WASHINGTON, D.C. May 11, 2020] Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (“Cogent”) today announced that Sean Wall

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 8, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 001-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Cogent Communications Reports First Quarter 2020 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter 2020 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approved a $0.02 increase

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Ex

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 7, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 6, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): March 17, 2020 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

CCOI / Cogent Communications Holdings, Inc. DEF 14A - - DEF 14A

QuickLinks - Click here to rapidly navigate through this document UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

First Amendment to Lease Agreement, dated February 28, 2020, between Sodium LLC and Cogent Communications, Inc. (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on March 2, 2020, and incorporated herein by reference).

EXHIBIT 10.2 FIRST AMENDMENT TO LEASE AGREEMENT THIS FIRST AMENDMENT TO LEASE AGREEMENT (this "Amendment") is made and entered into as of 28th day of February 2020 by and between Sodium LLC, a Delaware limited liability company, (hereinafter referred to as "Landlord"), having an office for purposes of notices hereunder at 2450 N Street, N.W., Washington, DC 20037 and Cogent Communications, Inc. a

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): (February 28, 2020) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorpora

Subsidiaries (filed herewith)

Exhibit 21.1 In Effect as of February 1, 2020 Legal Entity Jurisdiction COGENT COMMUNICATIONS HOLDINGS, INC. (Delaware) subsidiaries: COGENT COMMUNICATIONS GROUP, INC. (Delaware) COGENT COMMUNICATIONS, INC. (Delaware) COGENT COMMUNICATIONS OF CALIFORNIA, INC. (Delaware) COGENT IH, LLC (Delaware) COGENT WG, LLC (Delaware) COGENT RB, LLC (Delaware) COGENT TW, LLC (Delaware) COGENT COMMUNICATIONS OF

Certification of Chief Financial Officer (furnished herewith)

Exhibit 32.2 Certification of Chief Financial Officer Pursuant to 18 U.S.C. § 1350, as created by Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned officer of Cogent Communications Holdings, Inc. (the “Company”) hereby certifies, to such officer’s knowledge, that: (i) the accompanying Annual Report on Form 10-K of the Company for the year ended December 31, 2019 (the “Report”) fully c

Annual Report - 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the fiscal year ended December 31, 2019 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the transition period from to Commission file number 000-5

Certification of Chief Executive Officer (furnished herewith)

Exhibit 32.1 Certification of Chief Executive Officer Pursuant to 18 U.S.C. § 1350, as created by Section 906 of the Sarbanes-Oxley Act of 2002, the undersigned officer of Cogent Communications Holdings, Inc. (the “Company”) hereby certifies, to such officer’s knowledge, that: (i) the accompanying Annual Report on Form 10-K of the Company for the year ended December 31, 2019 (the “Report”) fully c

Exhibit 4.10

Exhibit 4.10 DESCRIPTION OF THE COMPANY’S COMMON STOCK REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 Cogent Communications Holdings, Inc. (“our,” “we” or the “Company”) has one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), our common stock, par value $0.001 per share (“Common Stock”). Description

Cogent Communications Reports Fourth Quarter and Full Year 2019 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2019 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approved a

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): (February 27, 2020) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorpora

Amendment No. 8 to Employment Agreement of David Schaeffer, dated February 14, 2020 (previously filed as Exhibit 10.1 to our Current Report on Form 8-K, filed on February 19, 2020, and incorporated herein by reference).

EX-10.1 2 tm209393d1ex10-1.htm EXHIBIT 10.1 EXHIBIT 10.1 Amendment No. 8 to Employment Agreement of David Schaeffer This amendment is made by and between Cogent Communications, Inc. (the “Company”) and David Schaeffer (“Executive”). It amends the employment agreement between the parties dated February 7, 2000 as amended. The second and third sentences of section 2 are replaced with the following:

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 19, 2020 (February 14, 2020) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdi

Restricted Stock Award, dated as of February 14, 2020, between the Company and David Schaeffer (previously filed as Exhibit 10.2 to our Current Report on Form 8-K, filed on February 19, 2020, and incorporated herein by reference).

EX-10.2 3 tm209393d1ex10-2.htm EXHIBIT 10.2 Exhibit 10.2 RESTRICTED STOCK AWARD Name: Dave Schaeffer Cogent Communications Holdings, Inc. Grant Date: February 14, 2020 2017 Incentive Award Plan (the “Plan”) Grant: Effective as of the Grant Date specified above you have been granted 84,000 (eighty-four thousand) Shares (“Time Vesting Shares”) and up to 105,000 (one hundred five thousand) performanc

CCOI / Cogent Communications Holdings, Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 11)* Name of issuer: Cogent Communications Holdings Inc Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 31, 2019 Check the appropriate box to designate the rule pursuant to which this Sche

Cogent Communications Reports Third Quarter 2019 Results, Appoints Two New Directors and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Third Quarter 2019 Results, Appoints Two New Directors and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Coge

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 7, 2019 (November 4, 2019) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdict

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2019 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): August 8, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Communications Reports Second Quarter 2019 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Second Quarter 2019 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approves a $0.02 increas

Quarterly Report - FORM 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2019 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Exa

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 25, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Indenture related to the 4.375% Senior Notes due 2024, dated as of June 25, 2019, among Cogent Communications Group, Inc., the guarantors named therein, Wilmington Trust, National Association, as trustee, Deutsche Bank AG, London Branch, as paying agent, and Deutsche Bank Luxembourg S.A., as authentication agent and registrar (previously filed as Exhibit 4.1 to our Current Report on Form 8-K, filed on June 25, 2019, and incorporated herein by reference).

Exhibit 4.1 EXECUTION VERSION INDENTURE Dated as of June 25, 2019 Among COGENT COMMUNICATIONS GROUP, INC., THE GUARANTORS PARTY HERETO WILMINGTON TRUST, NATIONAL ASSOCIATION, as Trustee, DEUTSCHE BANK AG, LONDON BRANCH, as Paying Agent, and DEUTSCHE BANK LUXEMBOURG S.A., as Registrar and Authentication Agent 4.375% SENIOR NOTES DUE 2024 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS AND INCORPORATIO

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 20, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): June 18, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation)

Cogent Launches Notes Offering

EX-99.1 2 a19-113983ex99d1.htm EX-99.1 Exhibit 99.1 Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson + 1 (202) 295-4212 + 1 (202) 295-4299 [email protected] [email protected] Cogent Launches Notes Offering WASHINGTON, D.C. June 18, 2019 — Cogent Communications Holdings, Inc. (NASDAQ: CCOI) (“Cogent Communications”) today announced that Cogent Commun

CCOI / Cogent Communications Holdings, Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 10)* Name of issuer: Cogent Communications Holdings Inc Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: April 30, 2019 Check the appropriate box to designate the rule pursuant to which this Schedul

Cogent Communications Reports First Quarter 2019 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports First Quarter 2019 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approves a $0.02 increase

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 2, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended March 31, 2019 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC. (Ex

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): May 1, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporation) (C

CCOI / Cogent Communications Holdings, Inc. S-8 S-8

As filed with the Securities and Exchange Commission on May 1, 2019. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 COGENT COMMUNICATIONS HOLDINGS, INC. (Exact name of registrant as specified in its charter) Delaware 46-5706863 (State or other jurisdiction of incorporation or organizatio

CCOI / Cogent Communications Holdings, Inc. DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant o Check the appropriate box: o Preliminary Proxy Statement o Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) o Defin

First Amendment to Cogent Communications Holdings, Inc. 2017 Incentive Award Plan (incorporated by reference to Appendix B of the Company’s Definitive Proxy Statement on Schedule 14A filed March 15, 2019 (File No. 000-51829)).

QuickLinks - Click here to rapidly navigate through this document UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

CCOI / Cogent Communications Holdings, Inc. 10-K (Annual Report)

Use these links to rapidly review the document TABLE OF CONTENTS ITEM 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. For the fiscal year ended December 31, 2018 OR o TRANSITION REPORT PURSUANT TO SECTI

Subsidiaries (filed herewith)

EX-21 2 a2237655zex-21.htm EX-21 EXHIBIT 21.1 In Effect as of February 1, 2019 Legal Entity Jurisdiction COGENT COMMUNICATIONS HOLDINGS, INC. (Delaware) subsidiaries: COGENT COMMUNICATIONS GROUP, INC. (Delaware) COGENT COMMUNICATIONS, INC. (Delaware) COGENT COMMUNICATIONS OF CALIFORNIA, INC. (Delaware) COGENT IH, LLC (Delaware) COGENT WG, LLC (Delaware) COGENT COMMUNICATIONS OF D.C., INC. (Delawar

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 21, 2019 (September 14, 2018) Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other juri

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): February 21, 2019 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporati

Cogent Communications Reports Fourth Quarter and Full Year 2018 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Fourth Quarter and Full Year 2018 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approves a

CCOI / Cogent Communications Holdings, Inc. / VANGUARD GROUP INC Passive Investment

cogentcommunicationsholdings.htm - Generated by SEC Publisher for SEC Filing SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 9 )* Name of issuer: Cogent Communications Holdings Inc Title of Class of Securities: Common Stock CUSIP Number: 19239V302 Date of Event Which Requires Filing of this Statement: December 31, 201

Cogent Communications Reports Third Quarter 2018 Results and Increases Regular Quarterly Dividend on Common Stock

Exhibit 99.1 FOR IMMEDIATE RELEASE Cogent Contacts: For Public Relations: For Investor Relations: Jocelyn Johnson John Chang + 1 (202) 295-4299 + 1 (202) 295-4212 [email protected] [email protected] Cogent Communications Reports Third Quarter 2018 Results and Increases Regular Quarterly Dividend on Common Stock Financial and Business Highlights · Cogent approves a 3.7% increase

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): November 1, 2018 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporatio

CCOI / Cogent Communications Holdings, Inc. 10-Q (Quarterly Report)

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2018 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File No. 000-51829 COGENT COMMUNICATIONS HOLDINGS, INC.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of Earliest Event Reported): September 14, 2018 Cogent Communications Holdings, Inc. (Exact name of registrant as specified in its charter) Delaware 000-51829 46-5706863 (State or other jurisdiction of incorporat