144 0001166976 XXXXXXXX LIVE 0001158324 Cogent Communications Holdings, Inc. 000-51829 2450 N. Street N.W. Washington DC 20037 202-295-4200 David Schaeffer Founder CEO Common Stock J.P. Morgan Securities LLC

390 Madison Avenue 6th Floor New York NY 10017

60000 4989600 49024304 11/25/2024 NASDAQ Common Stock 05/01/2009 Stock Vest Issuer N 5000 05/01/2009 Compensation Common Stock 04/30/2009 Stock Vest Issuer N 55000 04/30/2009 Compensation N David Schaeffer

C/o Cogent Communications Holdings Inc 2450 N. Street N.W. Washington DC 20037

Common Stock 09/10/2024 65000 4661481.85 David Schaeffer

C/o Cogent Communications Holdings Inc 2450 N. Street N.W. Washington DC 20037

Common Stock 08/27/2024 60000 4367044.54 11/25/2024 /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for David Schaeffer