| Jun 30, 2026 AForm 4 → | Jul 1, 4:52 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 3,445 | — | — | 58,693 | — | |
| Mar 12, 2019 SForm 4 → | Mar 13, 10:42 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 9,900 | $50.13 | $496,280 | 20,000 | −33.1% | plan? |
| Jan 1, 2019 AForm 4 → | Jan 3, 1:05 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 29,900 | — | plan? |
| Oct 1, 2018 AForm 4 → | Oct 1, 1:09 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 28,150 | — | plan? |
| Jul 1, 2018 AForm 4 → | Jul 3, 12:25 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 26,400 | — | plan? |
| May 16, 2018 SForm 4 → | May 17, 2:45 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 2,000 | $50.65 | $101,298 | 24,650 | −7.50% | plan? |
| May 8, 2018 SForm 4 → | May 9, 1:27 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 5,000 | $48.34 | $241,697 | 26,650 | −15.8% | plan? |
| Apr 1, 2018 AForm 4 → | Apr 2, 3:10 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 31,650 | — | plan? |
| Jan 1, 2018 AForm 4 → | Jan 2, 4:36 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 29,900 | — | plan? |
| Oct 1, 2017 AForm 4 → | Oct 3, 9:54 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 28,150 | — | plan? |
| Aug 7, 2017 SForm 4 → | Aug 8, 5:29 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 10,000 | $43.25 | $432,495 | 26,400 | — | plan? |
| Jul 1, 2017 AForm 4 → | Jul 3, 4:03 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 36,400 | — | plan? |
| May 3, 2017 AForm 4 → | May 3, 4:08 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 34,650 | — | plan? |
| Mar 16, 2017 SForm 4 → | Mar 16, 7:10 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 3,000 | $41.77 | $125,315 | 32,900 | −8.36% | plan? |
| Jan 1, 2017 AForm 4 → | Jan 3, 5:14 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 35,900 | — | plan? |
| Oct 1, 2016 AForm 4 → | Oct 3, 4:52 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 34,150 | — | plan? |
| Jul 1, 2016 AForm 4 → | Jul 1, 2:01 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 32,275 | — | plan? |
| Apr 1, 2016 AForm 4 → | Apr 4, 9:53 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 30,400 | — | plan? |
| Feb 29, 2016 SForm 4 → | Mar 2, 9:48 am EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 10,000 | $37.29 | $372,942 | 28,525 | −26.0% | plan? |
| Jan 1, 2016 AForm 4 → | Jan 5, 12:23 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 38,525 | — | plan? |
| Oct 1, 2015 AForm 4 → | Oct 1, 5:13 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 36,650 | — | plan? |
| Jul 1, 2015 AForm 4 → | Jul 1, 4:34 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 34,775 | — | plan? |
| Apr 1, 2015 AForm 4 → | Apr 1, 4:08 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 32,900 | — | plan? |
| Jan 1, 2015 AForm 4 → | Jan 2, 3:55 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 31,025 | — | plan? |