SEC ownership of Quantum-Si Inc

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001816431.

Comparable stake leader

Ph.D. Jonathan M. Rothberg

Disclosed value leader

Ph.D. Jonathan M. Rothberg

Comparable rows

50/50

Latest evidence

31 Mar 2026

Top shareholders Insider holders Latest transactions
Public ticker
QSI, QSIAW on Nasdaq
Parsed ownership sources
13D/G, 3/4/5, and 13F
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder
Ph.D. Jonathan M. Rothberg
Ranking: Comparable ownership first, then disclosed value
Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 3 signals
Comparable ownership rows
50 of 50
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder
Ph.D. Jonathan M. Rothberg
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date
31 Mar 2026
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0001816431
Issuer location
Branford, CT

Ownership snapshot

Top shareholders of Quantum-Si Inc (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader
Ph.D. Jonathan M. Rothberg
Disclosed value leader
Ph.D. Jonathan M. Rothberg
Comparable rows
50/50
Latest evidence
31 Mar 2026
13D/G 3/4/5 13F Lead comparable stake: 100% 13D/G row: Ph.D. Jonathan M. Rothberg Showing 1-8 of 50 holder rows.

Quick read

Ph.D. Jonathan M. Rothberg leads the comparable SEC ownership view at 100%.

50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens Ph.D. Jonathan M. Rothberg's linked filing trail.
Comparable ownership Top 5
Ph.D. Jonathan M. Rothberg 100%
Amova Asset Management Americas, ... 4.8%
Sumitomo Mitsui Trust Group, Inc. 4.8%
VANGUARD GROUP INC 4.8%
ARK Investment Management LLC 4.8%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 50 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
Ph.D. Jonathan M. Rothberg
13D/G 3/4/5
ROTHBERG JONATHAN M. · Director, 10%+ Owner
13D/G 3/4/5
100%
$23,326,875
19,937,500 shares
 $0 09 Sep 2025
Amova Asset Management Americas, Inc.
13D/G 13F
Nikko Asset Management Americas, Inc. · Company
13D/G 13F
4.8%
$7,217,902
5,965,208 shares
 $0 31 Dec 2024
Sumitomo Mitsui Trust Group, Inc.
13D/G 13F
Company
13D/G 13F
4.8%
$7,217,902
5,965,208 shares
 $0 31 Dec 2024
VANGUARD GROUP INC
13D/G
The Vanguard Group
13D/G
4.8%
$12,287,455
8,714,507 shares
 +$63,233 30 Sep 2025
ARK Investment Management LLC
13D/G 13F
Company
13D/G 13F
4.8%
$11,792,099
7,809,337 shares
 -$1,365,288 31 May 2025
Todd C. Bennett
3/4/5
Chief Commercial Officer
3/4/5
0.37%
$1,114,286
681,521 shares
 -$61,316 22 Sep 2025
BlackRock, Inc.
13F
Company
13F
7.3%
$10,383,169
13,414,949 shares
 — 31 Mar 2026
VANGUARD CAPITAL MANAGEMENT LLC
13F
Company
13F
3.8%
$5,434,956
7,021,907 shares
 — 31 Mar 2026
How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Forms 3/4/5 flow

Insider trading overview

Net insider flow leans to selling over the last 12 months. Net value: -$129,370.

Buys
$564,250
Insiders: 2
Sells
$693,621
Insiders: 6
Net
-$129,370
Shares: +35,933
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 609,890 Shares: 573,957
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 0 318,852 $0 $313,517 -$313,517
3-6 609,890 66,388 $564,250 $55,581 +$508,670
6-9 0 92,307 $0 $164,598 -$164,598
9-12 0 96,410 $0 $159,925 -$159,925

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-20 of 26 reporting-owner rows connected to Quantum-Si Inc. Open a relationship link for the CIK-to-CIK filing trail.

Rows
26
Largest Forms 3/4/5 holder
2012 JMR Trust Common LLC
Net 12M change
-$129,371
Latest report
22 Jun 2026
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
2012 JMR Trust Common LLC 10%+ Owner $22,089,791 Mixed 10 Jun 2021
James B. Tananbaum Director $14,911,041 Mixed 10 Jun 2021
Ph.D. Jonathan M. Rothberg Director, 10%+ Owner $10,608,966 -$80,112 -0.75% Median 18 May 2026
John Viii Stark Chief Executive Officer, Director $3,499,941 Mixed 10 Jan 2022
Jeffrey Alan Hawkins President & CEO, Director $3,299,151 -$274,004 -7.7% Filing P/S 22 Jun 2026
Jeffry R. Keyes Chief Financial Officer $1,550,189 -$113,560 -6.8% Filing P/S 22 Jun 2026
Todd C. Bennett Chief Commercial Officer $1,114,286 -$61,316 -5.2% Filing P/S 22 Sep 2025
Ph.D Christian LaPointe GC & Corp. Secretary $1,063,003 -$57,526 -5.1% Filing P/S 22 Jun 2026
John S. Vieceli Chief Product Officer $1,025,250 -$107,103 -9.5% Filing P/S 22 Jun 2026
Kevin L. Rakin Director $944,676 Median 18 May 2026
Charles R. Kummeth Director $661,770 +$459,800 +228% Median 18 May 2026
Matthew Dyer Chief Business Officer $590,106 Mixed 13 Jun 2022
Grace Johnston Chief Commercial Officer $353,915 Filing P/S 21 Jun 2024
Paula Dowdy Director $208,288 +$104,450 +101% Median 18 May 2026
Ruth A. Fattori Director $131,976 Median 18 May 2026
Vikram Bajaj Director $117,999 Mixed 16 Jun 2022
Scott Mendel Director $109,786 Median 18 May 2026
Amir Jafri Director $89,739 Median 18 May 2026
John P. Kenny Director $88,456 Median 18 May 2026
Brigid Makes Director $15,876 Median 18 May 2026

Recent insider transactions for Quantum-Si Inc

Showing up to 300 recent insider transactions from the last 12 months.

Insider Symbol Class Transaction % SEC-reported value SEC-reported price Shares Shares owned Date Ownership
Ph.D Christian LaPointe QSI Class A Common Stock Sale -0.65% $7,007 $0.8990 -7,794 1,182,429 23 Jun 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.24% $3,701 $0.8990 -4,117 1,724,349 23 Jun 2026 Direct
John S. Vieceli QSI Class A Common Stock Sale -1.31% $13,586 $0.8990 -15,112 1,140,434 23 Jun 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.31% $10,169 $0.8990 -11,311 3,669,802 23 Jun 2026 Direct
Ph.D Christian LaPointe QSI Class A Common Stock Sale -0.65% $7,462 $0.9574 -7,794 1,190,223 22 Jun 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.24% $3,941 $0.9574 -4,116 1,728,466 22 Jun 2026 Direct
John S. Vieceli QSI Class A Common Stock Sale -1.29% $14,467 $0.9574 -15,111 1,155,546 22 Jun 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.31% $10,828 $0.9574 -11,310 3,681,113 22 Jun 2026 Direct
Brigid Makes QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Ruth A. Fattori QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Amir Jafri QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Paula Dowdy QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
John P. Kenny QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Kevin Rakin QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Scott Mendel QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Charles R. Kummeth QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Jonathan M. Rothberg QSI Stock Option (right to buy) Award 251,185 251,185 18 May 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -2.11% $37,194 $0.9950 -37,381 1,732,582 21 Apr 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -2.22% $83,293 $0.9950 -83,712 3,692,423 21 Apr 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -2.07% $37,621 $1.01 -37,382 1,769,963 20 Apr 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -2.17% $84,248 $1.01 -83,712 3,776,135 20 Apr 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.24% $3,655 $0.8266 -4,422 1,807,345 23 Mar 2026 Direct
Ph.D. Christian LaPointe QSI Class A Common Stock Sale -0.51% $5,051 $0.8266 -6,110 1,198,017 23 Mar 2026 Direct
John S. Vieceli QSI Class A Common Stock Sale -0.95% $9,290 $0.8266 -11,239 1,170,657 23 Mar 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.31% $10,042 $0.8266 -12,149 3,859,847 23 Mar 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.23% $3,591 $0.8483 -4,233 1,811,767 20 Mar 2026 Direct
Ph.D. Christian LaPointe QSI Class A Common Stock Sale -0.48% $4,962 $0.8483 -5,849 1,204,127 20 Mar 2026 Direct
John S. Vieceli QSI Class A Common Stock Sale -0.9% $9,126 $0.8483 -10,758 1,181,896 20 Mar 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.3% $9,864 $0.8483 -11,628 3,871,996 20 Mar 2026 Direct
Jeffry R. Keyes QSI Class A Common Stock Award 56.1% 652,803 1,816,000 12 Mar 2026 Direct
Jeffry R. Keyes QSI Stock Option (Right to Buy) Award 780,847 780,847 12 Mar 2026 Direct
John S. Vieceli QSI Class A Common Stock Award 48.9% 391,681 1,192,654 12 Mar 2026 Direct
John S. Vieceli QSI Stock Option (Right to Buy) Award 468,508 468,508 12 Mar 2026 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Award 50.6% 1,305,606 3,883,624 12 Mar 2026 Direct
Jeffrey Alan Hawkins QSI Stock Option (Right to Buy) Award 1,561,695 1,561,695 12 Mar 2026 Direct
Ph.D. Christian LaPointe QSI Class A Common Stock Award 27.5% 261,121 1,209,976 12 Mar 2026 Direct
Ph.D. Christian LaPointe QSI Stock Option (Right to Buy) Award 312,339 312,339 12 Mar 2026 Direct
Charles R. Kummeth QSI Class A Common Stock Purchase 140.8% $459,800 $0.9196 500,000 855,000 05 Mar 2026 Direct
Paula Dowdy QSI Class A Common Stock Purchase 69% $104,450 $0.9505 109,890 269,107 05 Mar 2026 Direct
Amir Jafri QSI Stock Option (right to buy) Award 114,055 114,055 24 Feb 2026 Direct
John S. Vieceli QSI Class A Common Stock Sale -2.66% $27,979 $1.28 -21,927 800,973 22 Dec 2025 Direct
Christian LaPointe QSI Class A Common Stock Sale -1.24% $15,249 $1.28 -11,951 948,855 22 Dec 2025 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.74% $11,008 $1.28 -8,627 1,163,197 22 Dec 2025 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.91% $30,250 $1.28 -23,707 2,578,018 22 Dec 2025 Direct
Ph.D. Jonathan M. Rothberg QSI Class A Common Stock Sale -1.35% $80,112 $3.07 -26,095 1,904,866 16 Oct 2025 By NVR TR, LLC
Christian LaPointe QSI Class A Common Stock Sale -0.56% $8,770 $1.64 -5,364 960,806 23 Sep 2025 Direct
Jeffrey Alan Hawkins QSI Class A Common Stock Sale -0.41% $17,401 $1.64 -10,643 2,601,725 23 Sep 2025 Direct
John S. Vieceli QSI Class A Common Stock Sale -1.18% $16,093 $1.64 -9,843 822,900 23 Sep 2025 Direct
Jeffry R. Keyes QSI Class A Common Stock Sale -0.33% $6,332 $1.64 -3,873 1,171,824 23 Sep 2025 Direct
Todd C. Bennett QSI Class A Common Stock Sale -2.64% $30,218 $1.64 -18,482 681,521 23 Sep 2025 Direct
* marks a reported price that did not pass the local price check.
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