| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 10/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.4k | $0.00 | $0 | | 10/01/2023 |
| 08/24/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 550 | $68.85 | $37.9k | | 08/24/2023 |
| 07/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.4k | $0.00 | $0 | | 07/01/2023 |
| 05/30/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.1k | $63.14 | $69.5k | | 05/30/2023 |
| 04/01/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.5k | $0.00 | $0 | | 04/01/2023 |
| 03/13/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 600 | $61.66 | $37k | | 03/13/2023 |
| 01/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.7k | $0.00 | $0 | | 01/03/2023 |
| 11/21/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 962 | $57.83 | $55.6k | | 11/21/2022 |
| 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 |
| 06/02/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.4k | $60.88 | $82.2k | | 06/02/2022 |
| 04/01/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.5k | $0.00 | $0 | | 04/01/2022 |
| 11/23/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.6k | $77.37 | $123.8k | | 11/23/2021 |
| 10/01/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2021 |
| 08/24/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.8k | $71.99 | $126k | | 08/24/2021 |
| 05/17/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2.4k | $76.43 | $187.3k | | 05/17/2021 |
| 03/02/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1k | $59.34 | $62.3k | | 03/02/2021 |
| 01/01/2021 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 01/01/2021 |
| 11/09/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.2k | $58.55 | $70.3k | | 11/09/2020 |
| 10/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 10/01/2020 |
| 09/08/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1k | $65.97 | $69.3k | | 09/08/2020 |
| 07/01/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 07/01/2020 |
| 06/11/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.8k | $75.54 | $132.2k | | 06/11/2020 |
| 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 |
| 11/05/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 1.8k | $0.00 | $0 | | 11/05/2019 |