COGENT COMMUNICATIONS HOLDINGS, INC. 10-Q

ITEM 5. OTHER INFORMATION During the three months ended March 31, 2025, no director or officer of the Company adopted or terminated a “ Rule 10b5-1 trading arrangement” or “ non -Rule 10b5-1 trading arrangement,” as each term is defined in Item 408 of Regulation S-K. ​ Page 45 of 47 Table of Contents ITEM 6. EXHIBITS . (a) Exhibits Exhibit Number Description 4.1 ​ 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). 4.2 ​ Second Amendment to Base Indenture, dated as of April 11, 2025, 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 April 11, 2025, and incorporated herein by reference). 10.1# ​ 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). 10.2# ​ 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). 10.3 ​ Second Amendment to Lease Agreement, dated March 11, 2025, between Sodium LLC and Cogent Communications, LLC (previously filed as Exhibit 10.3 to our Current Report on Form 8-K, filed on March 12, 2025, and incorporated herein by reference). 31.1 ​ Certification of Chief Executive Officer (filed herewith) 31.2 ​ Certification of Chief Financial Officer (filed herewith) 32.1 ​ Certification of Chief Executive Officer (furnished herewith) 32.2 ​ Certification of Chief Financial Officer (furnished herewith) 101.1 ​ The following materials from the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2025, formatted in Inline Extensible Business Reporting Language (XBRL), include: (i) the Condensed Consolidated Statements of Comprehensive Loss, (ii) the Condensed Consolidated Balance Sheets, (iii) the Condensed Consolidated Statements of Cash Flows, and (iv) related notes (filed herewith). 104 ​ Cover Page Interactive Data File (the cover page XBRL tags are embedded within the iXBRL document). # Indicates a management contract or compensatory plan or arrangement in which directors or executive officers are eligible to participate. ​ ​ ​ Page 46 of 47 Table of Contents SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. ​ ​ ​ Date: May 8, 2025 COGENT COMMUNICATIONS HOLDINGS, INC. ​ ​ ​ By: /s/ David Schaeffer ​ ​ Name: David Schaeffer ​ ​ Title: Chief Executive Officer ​ ​ ​ Date: May 8, 2025 By: /s/ Thaddeus G. Weed ​ ​ Name: Thaddeus G. Weed ​ ​ Title: Chief Financial Officer and Treasurer ​ ​ ​ ​ Page 47 of 47