| Date | Name | Symbol | Type | Security | Shares | Price | Value | Ownership | Reported |
| 05/09/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 10k | $64.96 | $649.6k | | 05/09/2023 |
| 03/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.8k | $64.30 | $311.9k | | 03/03/2023 |
| 01/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 10k | $0.00 | $0 | | 01/03/2023 |
| 01/03/2023 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 19.4k | $0.00 | $0 | | 01/03/2023 |
| 12/02/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 9.7k | $56.51 | $548.2k | | 12/02/2022 |
| 12/01/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 4.8k | $0.00 | $0 | | 12/01/2022 |
| 09/09/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.8k | $52.35 | $253.9k | | 09/09/2022 |
| 06/02/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.8k | $60.49 | $293.4k | | 06/02/2022 |
| 05/04/2022 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 10k | $0.00 | $0 | | 05/04/2022 |
| 03/03/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.8k | $81.37 | $394.7k | | 03/03/2020 |
| 02/14/2020 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 19.4k | $0.00 | $0 | | 02/14/2020 |
| 12/31/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.2k | $66.07 | $280.8k | | 12/31/2019 |
| 12/03/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $61.74 | $308.7k | | 12/03/2019 |
| 09/05/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $60.00 | $300k | | 09/05/2019 |
| 06/13/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.4k | $60.84 | $85.2k | | 06/13/2019 |
| 06/05/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $58.50 | $292.5k | | 06/05/2019 |
| 05/06/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 1.5k | $57.11 | $85.7k | | 05/06/2019 |
| 05/01/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 19.4k | $0.00 | $0 | | 05/01/2019 |
| 03/12/2019 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $50.00 | $250k | | 03/12/2019 |
| 12/14/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 3k | $46.89 | $140.7k | | 12/14/2018 |
| 09/05/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.5k | $53.55 | $241k | | 09/05/2018 |
| 06/04/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 4.5k | $51.12 | $230k | | 06/04/2018 |
| 05/09/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 3k | $49.32 | $148k | | 05/09/2018 |
| 03/12/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 6k | $45.17 | $271k | | 03/12/2018 |
| 02/21/2018 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Grant | common stock | 19.4k | $0.00 | $0 | | 02/21/2018 |
| 12/07/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2k | $45.81 | $91.6k | | 12/07/2017 |
| 06/02/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2.2k | $41.20 | $92.7k | | 06/02/2017 |
| 03/15/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2.2k | $41.17 | $92.6k | | 03/15/2017 |
| 01/03/2017 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 20k | $41.52 | $830.3k | | 01/03/2017 |
| 12/13/2016 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 2k | $40.68 | $81.4k | | 12/13/2016 |
| 12/07/2016 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $37.91 | $189.5k | | 12/07/2016 |
| 06/03/2016 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $40.07 | $200.3k | | 06/03/2016 |
| 11/28/2012 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 10k | $21.10 | $211k | | 11/28/2012 |
| 02/27/2012 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 7.5k | $18.36 | $137.7k | | 02/27/2012 |
| 12/01/2011 | COGENT COMMUNICATIONS HOLDINGS, INC. | CCOI | Sale | common stock | 5k | $17.02 | $85.1k | | 12/01/2011 |
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