QSI · Quantum-Si Inc · Shareholders & Ownership

$1.18 +0.09 (+8.19%)

Market Cap

$238.58M

218.88M

Volume · Oct 20 6.16M Avg daily vol (3M) 5.27M

Every disclosed holder of QSI 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 QSI

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)	132	52,669,461	24.06%	Yes
Insiders (Forms 3, 4, 5)	0	0	0.00%	No
13D/G-only blocks	1	14,376,415	6.57%	Yes
Remaining	—	151,838,036	69.37%	Rest
Registered funds (N-PORT, not summed)	39	20,258,266	9.26%	No

Shares outstanding: 218,883,912, the issuer's latest cover-page count restated onto today's split basis.

Insiders are listed but not summed: the issuer has more than one class of common stock and Forms 3, 4 and 5 report one issuer-wide balance across them.

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 QSI

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	ROTHBERG JONATHAN M 13D CIK 1076352 · Unknown · Aug 26, 2026 Item 4 purpose: Other	14,376,415	6.57%	+100,000	Aug 26, 2026
1.1	ROTHBERG JONATHAN M Insider CIK 1076352 · May 18, 2026 Director, 10% Owner, issuer-wide, not summed	4,835,615	2.21%	—	May 18, 2026	Director, 10% Owner, issuer-wide, not summed
2	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	7,578,208	3.46%	+556,301	Jun 30, 2026	carried, not yet filed for the newest quarter
3	ARK Investment Management LLC 13F CIK 1697748 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	7,167,738	3.27%	+288,839	Jun 30, 2026	carried, not yet filed for the newest quarter
3.1	ARK Genomic Revolution ETF Fund S000042975 · Registered fund · Jul 31, 2026 ARK ETF Trust, not summed	6,760,803	3.09%	-167,540	Jul 31, 2026	ARK ETF Trust, not summed
4	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	5,353,930	2.45%	+479,200	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
5	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	5,225,352	2.39%	-8,189,597	Jun 30, 2026	carried, not yet filed for the newest quarter
5.1	BlackRock, Inc. 13G CIK 2012383 · Holding company · Jun 30, 2026 Rule 13d-1(b), qualified institution, not summed	4,598,208	2.10%	—	Jun 30, 2026	Rule 13d-1(b), qualified institution, not summed
5.2	iShares Biotechnology ETF Fund S000004350 · Registered fund · Jun 30, 2026 iShares Trust, not summed	1,197,863	0.55%	-25,671	Jun 30, 2026	iShares Trust, not summed
5.3	iShares Core S&P Total U.S. Stock Market ETF Fund S000004317 · Registered fund · Jun 30, 2026 iShares Trust, not summed	431,096	0.20%	+10,336	Jun 30, 2026	iShares Trust, not summed
6	Amova Asset Management Americas, Inc. 13F CIK 1480751 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	3,885,230	1.78%	-506,436	Jun 30, 2026	carried, not yet filed for the newest quarter
7	Sumitomo Mitsui Trust Group, Inc. 13F CIK 1475365 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	3,885,230	1.78%	-506,436	Jun 30, 2026	carried, not yet filed for the newest quarter
8	Hawkins Jeffrey Alan Insider CIK 1505034 · Sep 22, 2026 Director, President & CEO, issuer-wide, not summed	3,639,950	1.66%	-29,852	Sep 22, 2026	Director, President & CEO, issuer-wide, not summed
9	MILLENNIUM MANAGEMENT LLC 13F CIK 1273087 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	3,131,726	1.43%	+3,131,726	Jun 30, 2026	carried, not yet filed for the newest quarter
10	UBS Group AG 13F CIK 1610520 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	2,561,897	1.17%	+859,370	Jun 30, 2026	carried, not yet filed for the newest quarter
11	AQR CAPITAL MANAGEMENT LLC 13F CIK 1167557 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,348,665	1.07%	-43,514	Jun 30, 2026	carried, not yet filed for the newest quarter
12	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	2,236,526	1.02%	-1,598,595	Jun 30, 2026	carried, not yet filed for the newest quarter
13	JANE STREET GROUP, LLC 13F CIK 1595888 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	2,142,735	0.98%	+2,142,735	Jun 30, 2026	carried, not yet filed for the newest quarter
14	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	1,988,263	0.91%	-7,275	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
15	Keyes Jeffry R. Insider CIK 1557736 · Sep 22, 2026 Chief Financial Officer, issuer-wide, not summed	1,716,684	0.78%	-7,665	Sep 22, 2026	Chief Financial Officer, issuer-wide, not summed
16	RAKIN KEVIN Insider CIK 1184421 · May 18, 2026 Director, issuer-wide, not summed	1,220,512	0.56%	0	May 18, 2026	Director, issuer-wide, not summed
17	LaPointe Christian Insider CIK 1856912 · Sep 22, 2026 GC & Corp. Secretary, issuer-wide, not summed	1,167,913	0.53%	-14,516	Sep 22, 2026	GC & Corp. Secretary, issuer-wide, not summed
18	Vieceli John S. Insider CIK 2032947 · Jun 23, 2026 Chief Product Officer, issuer-wide, not summed	1,140,434	0.52%	-30,223	Jun 23, 2026	Chief Product Officer, issuer-wide, not summed
19	SUSQUEHANNA INTERNATIONAL GROUP, LLP 13F CIK 1446194 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,116,750	0.51%	-347,818	Jun 30, 2026	carried, not yet filed for the newest quarter
20	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	1,116,683	0.51%	-569	Jun 30, 2026	carried, not yet filed for the newest quarter
21	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	890,741	0.41%	-2,879,948	Jun 30, 2026	carried, not yet filed for the newest quarter
22	VANGUARD RUSSELL 2000 INDEX FUND Fund S000030003 · Registered fund · May 31, 2026 VANGUARD SCOTTSDALE FUNDS, not summed	862,344	0.39%	+85,041	May 31, 2026	VANGUARD SCOTTSDALE FUNDS, not summed
23	Kummeth Charles R. Insider CIK 1534980 · May 18, 2026 Director, issuer-wide, not summed	855,000	0.39%	0	May 18, 2026	Director, issuer-wide, not summed
24	Fosun International Ltd 13F CIK 1447884 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	743,935	0.34%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
25	Bennett Todd C. Insider CIK 1690473 · Sep 23, 2025 Chief Commercial Officer, issuer-wide, not summed	681,521	0.31%	-36,964	Sep 23, 2025	Chief Commercial Officer, issuer-wide, not summed
26	RENAISSANCE TECHNOLOGIES LLC 13F CIK 1037389 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	553,871	0.25%	+435,971	Jun 30, 2026	carried, not yet filed for the newest quarter
27	VANGUARD HEALTH CARE INDEX FUND Fund S000004450 · Registered fund · May 31, 2026 VANGUARD WORLD FUND, not summed	539,508	0.25%	+46,049	May 31, 2026	VANGUARD WORLD FUND, not summed
28	VANGUARD PORTFOLIO MANAGEMENT LLC 13F CIK 2100121 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	497,098	0.23%	-1,023,548	Jun 30, 2026	carried, not yet filed for the newest quarter
29	GOLDMAN SACHS GROUP INC 13F CIK 886982 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	476,288	0.22%	+32,111	Jun 30, 2026	carried, not yet filed for the newest quarter
29.1	Goldman Sachs Absolute Return Tracker Fund Fund S000020314 · Registered fund · Jun 30, 2026 GOLDMAN SACHS TRUST, not summed	58,539	0.03%	+22,329	Jun 30, 2026	GOLDMAN SACHS TRUST, not summed
30	NORTHERN TRUST CORP 13F CIK 73124 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	450,531	0.21%	-810,170	Jun 30, 2026	carried, not yet filed for the newest quarter
31	Invesco Ltd. 13F CIK 914208 · Investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	443,929	0.20%	+37,239	Jun 30, 2026	carried, not yet filed for the newest quarter
31.1	Invesco RAFI US 1500 Small-Mid ETF Fund S000013120 · Registered fund · Jul 31, 2026 Invesco Exchange-Traded Fund Trust, not summed	425,347	0.19%	+4,488	Jul 31, 2026	Invesco Exchange-Traded Fund Trust, not summed
31.2	Invesco Nasdaq Biotechnology ETF Fund S000072469 · Registered fund · May 31, 2026 Invesco Exchange-Traded Fund Trust II, not summed	10,304	0.00%	-629	May 31, 2026	Invesco Exchange-Traded Fund Trust II, not summed
32	BNP PARIBAS ARBITRAGE, SA 13F CIK 1166588 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	398,598	0.18%	+360,208	Jun 30, 2026	carried, not yet filed for the newest quarter
33	IEQ CAPITAL, LLC 13F CIK 1779789 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	350,816	0.16%	-6,872	Jun 30, 2026	carried, not yet filed for the newest quarter
34	Aster Capital Management (DIFC) Ltd 13F CIK 2040915 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	344,510	0.16%	+344,510	Jun 30, 2026	carried, not yet filed for the newest quarter
35	MORGAN STANLEY 13F CIK 895421 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	323,482	0.15%	+193,542	Jun 30, 2026	carried, not yet filed for the newest quarter
36	IQ EQ FUND MANAGEMENT (IRELAND) Ltd 13F CIK 1620943 · Exempt reporting adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	321,134	0.15%	+29,027	Jun 30, 2026	carried, not yet filed for the newest quarter
37	Knollwood Investment Advisory, LLC 13F CIK 1999346 · Investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	300,000	0.14%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
38	IMC-Chicago, LLC 13F CIK 1452861 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	285,758	0.13%	+64,882	Jun 30, 2026	carried, not yet filed for the newest quarter
39	Dowdy Paula Insider CIK 2016312 · May 18, 2026 Director, issuer-wide, not summed	269,107	0.12%	0	May 18, 2026	Director, issuer-wide, not summed
40	BRIDGEWAY CAPITAL MANAGEMENT, LLC 13F CIK 1107261 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	206,100	0.09%	-55,000	Jun 30, 2026	carried, not yet filed for the newest quarter
40.1	Ultra-Small Company Market Fund Fund S000004424 · Registered fund · Jun 30, 2026 Bridgeway Funds, Inc., not summed	200,000	0.09%	-55,000	Jun 30, 2026	Bridgeway Funds, Inc., not summed
41	BARCLAYS PLC 13F CIK 312069 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	205,690	0.09%	+166,553	Jun 30, 2026	carried, not yet filed for the newest quarter
42	XTX Topco Ltd 13F CIK 1828301 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	177,680	0.08%	-211,574	Jun 30, 2026	carried, not yet filed for the newest quarter
43	Fattori Ruth A Insider CIK 1306826 · May 18, 2026 Director, issuer-wide, not summed	170,512	0.08%	0	May 18, 2026	Director, issuer-wide, not summed
44	SIMPLEX TRADING, LLC 13F CIK 1488542 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	165,293	0.08%	+74,762	Jun 30, 2026	carried, not yet filed for the newest quarter
45	Verdence Capital Advisors LLC 13F CIK 1719305 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	158,305	0.07%	-45,550	Jun 30, 2026	carried, not yet filed for the newest quarter
46	Mariner, LLC 13F CIK 1373442 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	157,689	0.07%	-42,003	Jun 30, 2026	carried, not yet filed for the newest quarter
47	Shay Capital LLC 13F CIK 1723643 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	150,922	0.07%	0	Jun 30, 2026	carried, not yet filed for the newest quarter
48	Mendel Scott Insider CIK 1515051 · May 18, 2026 Director, issuer-wide, not summed	141,843	0.06%	0	May 18, 2026	Director, issuer-wide, not summed
49	VANGUARD RUSSELL 2000 VALUE INDEX FUND Fund S000030004 · Registered fund · May 31, 2026 VANGUARD SCOTTSDALE FUNDS, not summed	132,626	0.06%	+16,989	May 31, 2026	VANGUARD SCOTTSDALE FUNDS, not summed
50	FMR LLC 13F CIK 315066 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	123,767	0.06%	+91,799	Jun 30, 2026	carried, not yet filed for the newest quarter
50.1	Fidelity Extended Market Index Fund Fund S000006021 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	907,406	0.41%	+401,798	May 31, 2026	Fidelity Concord Street Trust, not summed
50.2	Fidelity Total Market Index Fund Fund S000006026 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	328,187	0.15%	0	May 31, 2026	Fidelity Concord Street Trust, not summed
50.3	Fidelity Series Total Market Index Fund Fund S000065248 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	270,587	0.12%	+5,807	May 31, 2026	Fidelity Concord Street Trust, not summed
50.4	Fidelity Nasdaq Composite Index Fund Fund S000055366 · Registered fund · May 31, 2026 Fidelity Concord Street Trust, not summed	111,123	0.05%	0	May 31, 2026	Fidelity Concord Street Trust, not summed
50.5	Fidelity ZERO Total Market Index Fund Fund S000063106 · Registered fund · Jul 31, 2026 Fidelity Concord Street Trust, not summed	106,167	0.05%	+24,954	Jul 31, 2026	Fidelity Concord Street Trust, not summed

4 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 167 holders

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Key facts CIK 1816431 CUSIP 74765K105 13F (30d) 11 filings 11 filers Visit website Investor relations