| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 10/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.7k | $0.00 | $0 | | 01/03/2023 |
| 10/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.4k | $0.00 | $0 | | 10/01/2023 |
| 07/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.4k | $0.00 | $0 | | 07/01/2023 |
| 06/14/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.2k | $65.00 | $273.1k | | 06/14/2023 |
| 05/11/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 3.8k | $65.00 | $246.9k | | 05/11/2023 |
| 04/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.5k | $0.00 | $0 | | 04/01/2023 |
| 10/01/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.6k | $0.00 | $0 | | 10/01/2022 |
| 07/01/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.5k | $0.00 | $0 | | 07/01/2022 |
| 04/01/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.5k | $0.00 | $0 | | 04/01/2022 |
| 10/01/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2021 |
| 05/03/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5.8k | $76.08 | $437.5k | | 05/03/2021 |
| 01/01/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2021 |
| 10/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2020 |
| 07/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 07/01/2020 |
| 04/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 04/01/2020 |
| 01/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2020 |
| 10/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2019 |
| 07/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 07/01/2019 |
| 04/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 04/01/2019 |
| 03/12/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 9.9k | $50.13 | $496.3k | | 03/12/2019 |
| 01/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2019 |
| 10/01/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2018 |
| 07/01/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 07/01/2018 |
| 05/16/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2k | $50.65 | $101.3k | | 05/16/2018 |
| 05/08/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $48.34 | $241.7k | | 05/08/2018 |
| 04/01/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 04/01/2018 |
| 01/01/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2018 |
| 07/01/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 07/01/2017 |
| 03/16/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 3k | $41.77 | $125.3k | | 03/16/2017 |
| 01/01/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2017 |
| 06/14/2013 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 3k | $27.67 | $83k | | 06/14/2013 |
| 10/01/2012 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 2.5k | $0.00 | $0 | | 10/01/2012 |
| 07/01/2012 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 2.5k | $0.00 | $0 | | 07/01/2012 |
| 04/01/2012 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 2.5k | $0.00 | $0 | | 04/01/2012 |
| 01/05/2010 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Purchase | common stock | 5k | $9.93 | $49.6k | | 01/05/2010 |