CCOI · Cogent Communications Holdings, Inc. · Shareholders & Ownership

$7.41 -0.31 (-4.02%)

Russell 2000 member Rebalance outlook locked

Market Cap

$395.39M

51.22M

Volume · Oct 21 924.72K Avg daily vol (3M) 1.91M

Every disclosed holder of CCOI in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns CCOI

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	221	47,204,802	92.17%	Yes
Insiders (Forms 3, 4, 5)	14	2,780,323	5.43%	Yes
13D/G-only blocks	0	0	0.00%	Yes
Remaining	—	1,230,611	2.40%	Rest
Registered funds (N-PORT, not summed)	173	15,872,721	30.99%	No

Shares outstanding: 51,215,736, the issuer's latest cover-page count restated onto today's split basis.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of CCOI

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	TURTLE CREEK ASSET MANAGEMENT INC. 13F CIK 1484148 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	4,203,527	8.21%	-145,370	Jun 30, 2026	carried, not yet filed for the newest quarter
2	BlackRock, Inc. 13G CIK 2012383 · Holding company · Sep 30, 2026 Rule 13d-1(b), qualified institution, not summed	3,932,477	7.68%	-3,135,920	Sep 30, 2026	Rule 13d-1(b), qualified institution, not summed
2.1	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	7,376,384	14.40%	+301,012	Jun 30, 2026	carried, not yet filed for the newest quarter
2.2	iShares Core S&P Small-Cap ETF Fund S000004313 · Registered fund · Jun 30, 2026 iShares Trust, not summed	2,878,622	5.62%	+31,699	Jun 30, 2026	iShares Trust, not summed
2.3	iShares Russell 2000 ETF Fund S000004344 · Registered fund · Jun 30, 2026 iShares Trust, not summed	1,278,313	2.50%	+92,340	Jun 30, 2026	iShares Trust, not summed
2.4	iShares Russell 2000 Growth ETF Fund S000004343 · Registered fund · Jun 30, 2026 iShares Trust, not summed	463,177	0.90%	+67,704	Jun 30, 2026	iShares Trust, not summed
2.5	iShares S&P Small-Cap 600 Growth ETF Fund S000004314 · Registered fund · Jun 30, 2026 iShares Trust, not summed	231,899	0.45%	+9,289	Jun 30, 2026	iShares Trust, not summed
3	Park West Asset Management LLC 13F CIK 1386928 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	3,106,339	6.07%	+1,171,138	Jun 30, 2026	carried, not yet filed for the newest quarter
4	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	2,779,367	5.43%	+506,102	Jun 30, 2026	carried, not yet filed for the newest quarter
4.1	STATE STREET CORP 13G CIK 93751 · Bank · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	2,779,396	5.43%	—	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
4.2	State Street(R) SPDR(R) S&P(R) Telecom ETF Fund S000012323 · Registered fund · Jun 30, 2026 SPDR SERIES TRUST, not summed	913,046	1.78%	+521,214	Jun 30, 2026	SPDR SERIES TRUST, not summed
4.3	State Street(R) SPDR(R) Portfolio S&P 600(TM) Small Cap ETF Fund S000041317 · Registered fund · Jun 30, 2026 SPDR SERIES TRUST, not summed	440,422	0.86%	+1,950	Jun 30, 2026	SPDR SERIES TRUST, not summed
4.4	State Street(R) SPDR(R) S & P 600(TM) Small Cap Growth ETF Fund S000006990 · Registered fund · Jun 30, 2026 SPDR SERIES TRUST, not summed	136,583	0.27%	+1,333	Jun 30, 2026	SPDR SERIES TRUST, not summed
4.5	State Street(R) SPDR(R) S & P 600(TM) Small Cap Value ETF Fund S000006974 · Registered fund · Jun 30, 2026 SPDR SERIES TRUST, not summed	120,072	0.23%	+3,602	Jun 30, 2026	SPDR SERIES TRUST, not summed
5	VANGUARD PORTFOLIO MANAGEMENT LLC 13F CIK 2100121 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,384,929	4.66%	-363,830	Jun 30, 2026	carried, not yet filed for the newest quarter
5.1	VANGUARD PORTFOLIO MANAGEMENT LLC 13G CIK 2100121 · Registered investment adviser · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	2,431,530	4.75%	-359,612	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
6	EdgePoint Investment Group Inc. 13F CIK 1481669 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,283,378	4.46%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
7	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,037,716	3.98%	-82,815	Jun 30, 2026	carried, not yet filed for the newest quarter
8	SCHAEFFER DAVE Insider CIK 1166976 · May 4, 2026 Director, CHAIRMAN, CEO, AND PRESIDENT, issuer-wide	1,868,133	3.65%	+1,000,000	May 4, 2026	Director, CHAIRMAN, CEO, AND PRESIDENT, issuer-wide
9	Newtyn Management, LLC 13F CIK 1569241 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,655,895	3.23%	+55,895	Jun 30, 2026	carried, not yet filed for the newest quarter
10	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	1,441,723	2.82%	-101,500	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
11	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,245,445	2.43%	+39,810	Jun 30, 2026	carried, not yet filed for the newest quarter
12	CITADEL ADVISORS LLC 13F CIK 1423053 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	1,172,541	2.29%	+746,261	Jun 30, 2026	carried, not yet filed for the newest quarter
13	VANGUARD SMALL-CAP INDEX FUND Fund S000002845 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	1,033,231	2.02%	-65,999	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
14	MAGNOLIA GROUP, LLC 13F CIK 1618376 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	979,686	1.91%	-310,518	Jun 30, 2026	carried, not yet filed for the newest quarter
15	GOLDMAN SACHS GROUP INC 13F CIK 886982 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	973,138	1.90%	+260,204	Jun 30, 2026	carried, not yet filed for the newest quarter
15.1	Goldman Sachs Small Cap Equity Insights Fund Fund S000009329 · Registered fund · Jul 31, 2026 Goldman Sachs Trust, not summed	157,637	0.31%	+134,525	Jul 31, 2026	Goldman Sachs Trust, not summed
15.2	Goldman Sachs Small Cap Growth Insights Fund Fund S000014930 · Registered fund · Jul 31, 2026 Goldman Sachs Trust, not summed	68,569	0.13%	+33,419	Jul 31, 2026	Goldman Sachs Trust, not summed
15.3	Goldman Sachs Variable Insurance Trust Small Cap Equity Insights Fund Fund S000009355 · Registered fund · Jun 30, 2026 Goldman Sachs Variable Insurance Trust, not summed	40,787	0.08%	—	Jun 30, 2026	Goldman Sachs Variable Insurance Trust, not summed
15.4	Goldman Sachs Small Cap Value Insights Fund Fund S000014929 · Registered fund · Jul 31, 2026 Goldman Sachs Trust, not summed	25,709	0.05%	—	Jul 31, 2026	Goldman Sachs Trust, not summed
15.5	Goldman Sachs Absolute Return Tracker Fund Fund S000020314 · Registered fund · Jun 30, 2026 GOLDMAN SACHS TRUST, not summed	275	0.00%	-378	Jun 30, 2026	GOLDMAN SACHS TRUST, not summed
16	CHARLES SCHWAB INVESTMENT MANAGEMENT INC 13F CIK 884546 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	805,244	1.57%	+45,127	Jun 30, 2026	carried, not yet filed for the newest quarter
16.1	Schwab Fundamental U.S. Small Company ETF Fund S000040878 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	227,640	0.44%	+39,216	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
16.2	Schwab U.S. Small-Cap ETF Fund S000026636 · Registered fund · May 31, 2026 SCHWAB STRATEGIC TRUST, not summed	226,933	0.44%	-3,488	May 31, 2026	SCHWAB STRATEGIC TRUST, not summed
16.3	Schwab Small-Cap Index Fund Fund S000005912 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	119,992	0.23%	+13,542	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
16.4	Schwab Fundamental U.S. Small Company Index Fund Fund S000016767 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	78,999	0.15%	+18,640	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
16.5	Schwab Total Stock Market Index Fund Fund S000005913 · Registered fund · Jul 31, 2026 SCHWAB CAPITAL TRUST, not summed	34,906	0.07%	0	Jul 31, 2026	SCHWAB CAPITAL TRUST, not summed
17	GILDER GAGNON HOWE & CO LLC 13F CIK 902464 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	783,783	1.53%	+284,493	Jun 30, 2026	carried, not yet filed for the newest quarter
18	Broad Run Investment Management, LLC 13F CIK 1568621 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	660,130	1.29%	-3,070	Jun 30, 2026	carried, not yet filed for the newest quarter
19	MORGAN STANLEY 13F CIK 895421 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	627,593	1.23%	-1,255,479	Jun 30, 2026	carried, not yet filed for the newest quarter
19.1	E*TRADE No Fee Total Market Index Fund Fund S000090722 · Registered fund · Jul 31, 2026 E Trade Trust, not summed	142	0.00%	0	Jul 31, 2026	E Trade Trust, not summed
20	AQR CAPITAL MANAGEMENT LLC 13F CIK 1167557 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	615,561	1.20%	+405,652	Jun 30, 2026	carried, not yet filed for the newest quarter
21	Harspring Capital Management, LLC 13F CIK 1652327 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	599,418	1.17%	-487,582	Jun 30, 2026	carried, not yet filed for the newest quarter
22	VANGUARD SMALL-CAP GROWTH INDEX FUND Fund S000002846 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	593,234	1.16%	-22,696	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
23	HRT FINANCIAL LP 13F CIK 1475597 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	557,674	1.09%	+48,579	Jun 30, 2026	carried, not yet filed for the newest quarter
24	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	541,481	1.06%	+12,968	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
25	NORTHERN TRUST CORP 13F CIK 73124 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	516,683	1.01%	+19,488	Jun 30, 2026	carried, not yet filed for the newest quarter
25.1	Small Cap Index Fund Fund S000001245 · Registered fund · Jun 30, 2026 Northern Funds, not summed	25,444	0.05%	+3,467	Jun 30, 2026	Northern Funds, not summed
25.2	FlexShares Morningstar US Market Factor Tilt Index Fund Fund S000033312 · Registered fund · Jul 31, 2026 FlexShares Trust, not summed	14,852	0.03%	+13,928	Jul 31, 2026	FlexShares Trust, not summed
26	UBS Group AG 13F CIK 1610520 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	512,618	1.00%	+86,650	Jun 30, 2026	carried, not yet filed for the newest quarter
27	CenterBook Partners LP 13F CIK 1872738 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	503,457	0.98%	+9,174	Jun 30, 2026	carried, not yet filed for the newest quarter
28	Hennessy Focus Fund Fund S000038529 · Registered fund · Jul 31, 2026 Hennessy Funds Trust, not summed	492,488	0.96%	0	Jul 31, 2026	Hennessy Funds Trust, not summed
29	AYAL Capital Advisors Ltd 13F CIK 2011524 · Exempt reporting adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	400,000	0.78%	+400,000	Jun 30, 2026	carried, not yet filed for the newest quarter
30	FRONTIER CAPITAL MANAGEMENT CO LLC 13F CIK 351173 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	382,608	0.75%	-16,600	Jun 30, 2026	carried, not yet filed for the newest quarter
31	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	344,108	0.67%	+9,680	Jun 30, 2026	carried, not yet filed for the newest quarter
32	BNP PARIBAS ARBITRAGE, SA 13F CIK 1166588 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	328,127	0.64%	+250,321	Jun 30, 2026	carried, not yet filed for the newest quarter
33	Granahan Investment Management, LLC 13F CIK 1026710 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	302,653	0.59%	-14,794	Jun 30, 2026	carried, not yet filed for the newest quarter
34	PDT Partners, LLC 13F CIK 1564702 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	296,439	0.58%	+12,810	Jun 30, 2026	carried, not yet filed for the newest quarter
35	D. E. Shaw & Co., Inc. 13F CIK 1009207 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	284,694	0.56%	-454,121	Jun 30, 2026	carried, not yet filed for the newest quarter
36	SUSQUEHANNA INTERNATIONAL GROUP, LLP 13F CIK 1446194 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	280,790	0.55%	+150,677	Jun 30, 2026	carried, not yet filed for the newest quarter
37	Invesco Ltd. 13F CIK 914208 · Investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	268,923	0.53%	+26,497	Jun 30, 2026	carried, not yet filed for the newest quarter
37.1	Invesco RAFI US 1500 Small-Mid ETF Fund S000013120 · Registered fund · Jul 31, 2026 Invesco Exchange-Traded Fund Trust, not summed	130,358	0.25%	+6,737	Jul 31, 2026	Invesco Exchange-Traded Fund Trust, not summed
37.2	Invesco S&P SmallCap 600 Revenue ETF Fund S000064596 · Registered fund · May 31, 2026 Invesco Exchange-Traded Fund Trust II, not summed	50,799	0.10%	+4,302	May 31, 2026	Invesco Exchange-Traded Fund Trust II, not summed
37.3	Invesco S&P SmallCap Utilities & Communication Services ETF Fund S000028295 · Registered fund · May 31, 2026 Invesco Exchange-Traded Fund Trust II, not summed	8,179	0.02%	+238	May 31, 2026	Invesco Exchange-Traded Fund Trust II, not summed
37.4	Invesco Russell 2000 Dynamic Multifactor ETF Fund S000064608 · Registered fund · May 31, 2026 Invesco Exchange-Traded Self-Indexed Fund Trust, not summed	3,499	0.01%	+426	May 31, 2026	Invesco Exchange-Traded Self-Indexed Fund Trust, not summed
38	JPMORGAN CHASE & CO 13F CIK 19617 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	267,486	0.52%	-224,982	Jun 30, 2026	carried, not yet filed for the newest quarter
39	FourWorld Capital Management LLC 13F CIK 1770525 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	265,500	0.52%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
40	Bank of New York Mellon Corp 13F CIK 1390777 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	265,490	0.52%	+921	Jun 30, 2026	carried, not yet filed for the newest quarter
41	BANK OF AMERICA CORP /DE/ 13F CIK 70858 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	254,861	0.50%	-47,532	Jun 30, 2026	carried, not yet filed for the newest quarter
42	Jump Financial, LLC 13F CIK 1831577 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	251,745	0.49%	+251,745	Jun 30, 2026	carried, not yet filed for the newest quarter
43	VANGUARD RUSSELL 2000 INDEX FUND Fund S000030003 · Registered fund · May 31, 2026 VANGUARD SCOTTSDALE FUNDS, not summed	250,679	0.49%	+8,976	May 31, 2026	VANGUARD SCOTTSDALE FUNDS, not summed
44	BlackBarn Capital Partners LP 13F CIK 2010204 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	250,000	0.49%	-250,000	Jun 30, 2026	carried, not yet filed for the newest quarter
45	HERALD INVESTMENT MANAGEMENT Ltd 13F CIK 1512022 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	242,600	0.47%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
46	MYDA Advisors LLC 13F CIK 1589689 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	240,000	0.47%	+240,000	Jun 30, 2026	carried, not yet filed for the newest quarter
47	Palliser Capital (UK) Ltd 13F CIK 1881490 · Exempt reporting adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	236,393	0.46%	-98,051	Jun 30, 2026	carried, not yet filed for the newest quarter
48	PRINCIPAL FINANCIAL GROUP INC 13F CIK 1126328 · Insurance company · Jun 30, 2026 carried, not yet filed for the newest quarter	233,633	0.46%	+1,427	Jun 30, 2026	carried, not yet filed for the newest quarter
48.1	SmallCap S&P 600 Index Fund Fund S000007203 · Registered fund · Jul 31, 2026 Principal Funds, Inc, not summed	35,195	0.07%	-2,112	Jul 31, 2026	Principal Funds, Inc, not summed
48.2	SmallCap Growth Fund I Fund S000007175 · Registered fund · Jul 31, 2026 Principal Funds, Inc, not summed	4,289	0.01%	+1,215	Jul 31, 2026	Principal Funds, Inc, not summed
49	Squarepoint Ops LLC 13F CIK 1642575 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	226,035	0.44%	+174,787	Jun 30, 2026	carried, not yet filed for the newest quarter
50	XTX Topco Ltd 13F CIK 1828301 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	220,290	0.43%	+190,966	Jun 30, 2026	carried, not yet filed for the newest quarter

22 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 324 holders

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Key facts CIK 1158324 CUSIP 19239V302 13F (30d) 20 filings 20 filers Visit website Investor relations