| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 06/08/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 7.1k | $62.44 | $440.9k | | 06/08/2023 |
| 06/07/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 42.3k | $62.30 | $2.6M | | 06/06/2023 |
| 06/06/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 25.6k | $62.25 | $1.6M | | 06/06/2023 |
| 05/10/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 35k | $65.38 | $2.3M | | 05/10/2023 |
| 01/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 88k | $0.00 | $0 | | 01/03/2023 |
| 01/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 72k | $0.00 | $0 | | 01/03/2023 |
| 01/03/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 88k | $0.00 | $0 | | 01/03/2022 |
| 01/03/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 72k | $0.00 | $0 | | 01/03/2022 |
| 02/24/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 105k | $0.00 | $0 | | 02/24/2021 |
| 02/24/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 84k | $0.00 | $0 | | 02/24/2021 |
| 01/18/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Disposition | common stock | 16k | $0.00 | $0 | | 01/18/2021 |
| 03/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Disposition | common stock | 32.6k | $0.00 | $0 | | 03/01/2020 |
| 02/14/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 105k | $0.00 | $0 | | 02/14/2020 |
| 02/14/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 84k | $0.00 | $0 | | 02/14/2020 |
| 05/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 84k | $0.00 | $0 | | 05/01/2019 |
| 05/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 105k | $0.00 | $0 | | 05/01/2019 |
| 02/21/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 105k | $0.00 | $0 | | 02/21/2018 |
| 02/21/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 84k | $0.00 | $0 | | 02/21/2018 |
| 05/04/2016 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 170k | $0.00 | $0 | | 05/04/2016 |
| 04/15/2009 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 360k | $0.00 | $0 | | 04/15/2010 |