COGENT COMMUNICATIONS HOLDINGS, INC.

While the Notes are outstanding, scheduled payments of interest are required to be made on the Notes on a monthly basis. From and after the ARD, principal payments will also be required to be made on the Notes on a monthly basis. No principal payments will be due on the Notes prior to the ARD, unless certain rapid amortization or acceleration triggers are activated.

The legal final maturity date of the Notes is in April of 2055. If the Issuer has not repaid or refinanced any Note prior to the monthly payment date in April of 2030, additional interest will accrue thereon in an amount equal to the greater of (i) 5.0%per annum and (ii) the excess amount, if any, by which the sum of the following exceeds the interest rate for such Note: (A) the yield to maturity (adjusted to a “mortgage-equivalent basis” pursuant to the standards and practices of the Securities Industry and Financial Markets Association) on the ARD for such Note of the United States Treasury Security having a remaining term closest to 10 years;plus (B) 5.0%;plus (C) the post-ARD note spread of 3.00% applicable to such Note.