144 0001775672 XXXXXXXX LIVE 0001158324 COGENT COMMUNICATIONS HOLDINGS, INC. 000-51829 2450 N STREET, NW WASHINGTON DC 20037 2022954200 Chang John B. Officer Common Vanguard Marketing Corporation

5951 Luckett Court Suite A1 El Paso TX 79932-1882

2280 189240.00 49024304 11/12/2024 NASDAQ Common 05/03/2021 Stock Vest Issuer N 440 05/03/2021 Cash Common 11/01/2021 Stock Vest Issuer N 1840 11/01/2021 Cash N John Chang

2450 N Street N.W. Washington DC 20037

Common Stock 08/23/2024 2055 152065.77 John Chang

2450 N Street N.W. Washington DC 20037

Common Stock 09/12/2024 1400 100339.01 11/12/2024 John B. Chang