| Mar 12, 2019 GForm 4 → | Mar 12, 2:43 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,200 | — | — | 72,595 | — | plan? |
| Jan 1, 2019 AForm 4 → | Jan 3, 1:10 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 73,795 | — | plan? |
| Oct 1, 2018 AForm 4 → | Oct 1, 1:40 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 72,045 | — | plan? |
| Jul 1, 2018 AForm 4 → | Jul 3, 12:24 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 70,295 | — | plan? |
| Jun 20, 2018 GForm 4 → | Jun 20, 4:15 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 5,000 | — | — | 68,545 | — | plan? |
| Apr 1, 2018 AForm 4 → | Apr 2, 3:11 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 73,545 | — | plan? |
| Feb 26, 2018 GForm 4 → | Feb 26, 5:27 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,000 | — | — | 71,795 | — | plan? |
| Jan 1, 2018 AForm 4 → | Jan 2, 5:28 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 72,795 | — | plan? |
| Dec 5, 2017 PForm 4 → | Dec 6, 12:53 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 700 | $45.30 | $31,710 | 71,045 | +1.00% | plan? |
| Nov 7, 2017 GForm 4 → | Nov 8, 10:43 am EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,000 | — | — | 70,345 | — | plan? |
| Oct 1, 2017 AForm 4 → | Oct 2, 2:47 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 71,345 | — | plan? |
| Aug 31, 2017 GForm 4 → | Sep 1, 11:06 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 3,000 | — | — | 69,595 | — | plan? |
| Jul 1, 2017 AForm 4 → | Jul 3, 4:04 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 72,595 | — | plan? |
| May 3, 2017 AForm 4 → | May 3, 4:09 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 70,845 | — | plan? |
| Feb 27, 2017 SForm 4 → | Feb 28, 9:51 am EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 5,000 | $42.38 | $211,903 | 69,095 | −6.75% | plan? |
| Jan 1, 2017 AForm 4 → | Jan 3, 3:44 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,750 | — | — | 74,095 | — | plan? |
| Oct 1, 2016 AForm 4 → | Oct 4, 12:18 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 72,345 | — | plan? |
| Aug 23, 2016 GForm 4 → | Aug 23, 3:05 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 2,000 | — | — | 70,470 | — | plan? |
| Jul 1, 2016 AForm 4 → | Jul 1, 11:39 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 72,470 | — | plan? |
| May 18, 2016 GForm 4 → | May 18, 4:26 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 2,000 | — | — | 70,595 | — | plan? |
| Apr 1, 2016 AForm 4 → | Apr 4, 9:56 am EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 72,595 | — | plan? |
| Jan 29, 2016 GForm 4 → | Feb 1, 10:33 am EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 2,000 | — | — | 70,720 | — | plan? |
| Jan 1, 2016 AForm 4 → | Jan 5, 12:24 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 72,720 | — | plan? |
| Oct 1, 2015 AForm 4 → | Oct 1, 5:14 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 70,845 | — | plan? |
| Jul 1, 2015 AForm 4 → | Jul 1, 4:34 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 68,970 | — | plan? |
| Apr 1, 2015 AForm 4 → | Apr 1, 4:09 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 67,095 | — | plan? |
| Mar 12, 2015 SForm 4 → | Mar 12, 1:16 pm EDT | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 4,000 | $34.37 | $137,482 | 65,220 | −5.78% | plan? |
| Feb 27, 2015 SForm 4 → | Mar 2, 9:09 am EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 3,000 | $36.57 | $109,700 | 69,220 | −4.15% | plan? |
| Jan 14, 2015 GForm 4 → | Jan 14, 1:56 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 2,000 | — | — | 72,220 | — | plan? |
| Jan 1, 2015 AForm 4 → | Jan 2, 3:57 pm EST | COGENT COMMUNICATIONS HOLDINGS, INC.CCOI | 1,875 | — | — | 74,220 | — | plan? |