Vault-13

QUANTUM SI INC QSI

COM CL A · Common Stock · CUSIP 74765K105 · ISIN US74765K1051

102 institutional holders
47,584,25747.6m shares reported held*
$130.8mreported value*

* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Implied quarter-end price ≈ $2.75. Options: 8 managers hold calls ($1.6m notional), 7 hold puts ($712.0k).

Biggest calls

GROUP ONE TRADING LLC — $698.0k253.7k shares
CITADEL ADVISORS LLC — $323.0k117.4k shares
SIMPLEX TRADING, LLC — $252.0k91.9k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP — $216.0k78.5k shares
JANE STREET GROUP, LLC — $119.0k43.2k shares
WOLVERINE TRADING, LLC — $41.0k15.2k shares
CONCOURSE FINANCIAL GROUP SECURITIES, INC. — $00 shares
Cutler Group LLC / CA — $0400 shares

Biggest puts

GROUP ONE TRADING LLC — $503.0k182.9k shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP — $73.0k26.7k shares
CITADEL ADVISORS LLC — $70.0k25.5k shares
SIMPLEX TRADING, LLC — $37.0k13.7k shares
WOLVERINE TRADING, LLC — $28.0k10.2k shares
Cutler Group LLC / CA — $1.0k500 shares
CONCOURSE FINANCIAL GROUP SECURITIES, INC. — $00 shares

Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.

Major shareholders (over 5%)

Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.

HolderStakeChangeShares Last filed
ROTHBERG JONATHAN M 13D · may seek influence no change · filed 2026-08-28
Stated purposeIn connection with estate planning, entities owned by trusts created for the benefit of Dr. Jonathan Rothberg's children have entered into a trading plan pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended (the "Plan"), a copy of which is attached hereto as Exhibit 6. Pursuant to the Plan, sales of up to 8,947,746 shares of Class A common stock may be effected during the plan sales period beginning following the cooling-off period contained in Rule 10b5-1(c) on January 15, 2027 and ending on January 15, 2028 in accordance with the terms and conditions of the Plan. The sale of shares of Class A common stock under the Plan is subject to minimum price parameters included in the Plan, and there is no assurance that any shares of Class A common stock will be sold under… Full filing
100.0% no change 19.9m≈ $17.6m 2026-08-28

Fell to 5% or below in the last year: BlackRock, Inc. (2.3%, 2026-07-29)

Insider purchases and sales in Q3 2022

Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.

Officers and directors buying vs selling

Number of people, by quarter (10% owners not included)

BuyingSelling
404Q4 20: 0 buyingQ4 20: 0 sellingQ1 21: 0 buyingQ1 21: 0 sellingQ1 21Q2 21: 0 buyingQ2 21: 0 sellingQ3 21: 0 buyingQ3 21: 0 sellingQ3 21Q4 21: 0 buyingQ4 21: 0 sellingQ1 22: 0 buyingQ1 22: 4 sellingQ1 22Q2 22: 1 buyingQ2 22: 2 sellingQ3 22: 1 buyingQ3 22: 0 sellingQ3 22
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
Q4 20200—0——
Q1 20210—0——
Q2 20210—0——
Q3 20210—0——
Q4 20210—0——
Q1 20220—4$1.2m—
Q2 20221$79.2k2$10.5k—
Q3 20221$78.6k0——
DateInsiderTradeSharesPrice ValueTheir holding
2022-08-17 LaPointe Christian General Counsel & Corp. Secr. Bought 20,000 $3.93 $78.6k20.0k shares +10%

Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).

Holders, Q3 2022

#ManagerLocationShares Value% of their portfolioChangeShares change
1 ARK Investment Management LLC 0.25% of their portfolio ST. PETERSBURG, FL 13,237,79013.2m $36.4m $36.4m 0.25% —
2 BlackRock Inc. 0.00% of their portfolio New York, NY 6,354,7406.4m $17.5m $17.5m 0.00% —
3 GLENVIEW CAPITAL MANAGEMENT, LLC 0.36% of their portfolio NEW YORK, NY 5,096,9725.1m $14.0m $14.0m 0.36% —
4 VANGUARD GROUP INC 0.00% of their portfolio Valley Forge, PA 4,920,9224.9m $13.5m $13.5m 0.00% —
5 Foresite Capital Management IV, LLC 1.57% of their portfolio WEST HOLLYWOOD, CA 1,771,2491.8m $4.9m $4.9m 1.57% —
6 STATE STREET CORP 0.00% of their portfolio BOSTON, MA 1,723,3371.7m $4.7m $4.7m 0.00% —
7 GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio BOSTON, MA 1,613,4601.6m $4.4m $4.4m 0.00% —
8 DEERFIELD MANAGEMENT COMPANY, L.P. 0.08% of their portfolio New York, NY 1,400,0001.4m $3.9m $3.9m 0.08% —
9 Sumitomo Mitsui Trust Group, Inc. 0.00% of their portfolio CHIYODA-KU, TOKYO, M0 1,268,7711.3m $3.5m $3.5m 0.00% —
10 Amova Asset Management Americas, Inc. 0.04% of their portfolio New York, NY 1,268,7711.3m $3.4m $3.4m 0.04% —
11 Foresite Capital Management V, LLC 1.95% of their portfolio WEST HOLLYWOOD, CA 924,379924.4k $2.5m $2.5m 1.95% —
12 NORTHERN TRUST CORP 0.00% of their portfolio CHICAGO, IL 772,579772.6k $2.1m $2.1m 0.00% —
13 Fosun International Ltd 0.22% of their portfolio HONG KONG, F4 743,935743.9k $2.0m $2.0m 0.22% —
14 GUGGENHEIM CAPITAL LLC 0.02% of their portfolio CHICAGO, IL 678,717678.7k $1.9m $1.9m 0.02% —
15 Rubric Capital Management LP 0.09% of their portfolio NEW YORK, NY 672,385672.4k $1.8m $1.8m 0.09% —
16 Foresite Capital Opportunity Management V, LLC 5.23% of their portfolio Larkspur, CA 633,626633.6k $1.7m $1.7m 5.23% —
17 Neumann Advisory Hong Kong Ltd 0.41% of their portfolio CENTRAL, K3 427,631427.6k $1.2m $1.2m 0.41% —
18 GOLDMAN SACHS GROUP INC 0.00% of their portfolio NEW YORK, NY 396,105396.1k $1.1m $1.1m 0.00% —
19 Nuveen Asset Management, LLC 0.00% of their portfolio CHICAGO, IL 365,401365.4k $1.0m $1.0m 0.00% —
20 Bank of New York Mellon Corp 0.00% of their portfolio NEW YORK, NY 275,966276.0k $759.0k $759.0k 0.00% —
21 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio SAN FRANCISCO, CA 232,986233.0k $641.0k $641.0k 0.00% —
22 Clearline Capital LP 0.08% of their portfolio NEW YORK, NY 211,900211.9k $583.0k $583.0k 0.08% —
23 Swiss National Bank 0.00% of their portfolio ZURICH, V8 194,500194.5k $535.0k $535.0k 0.00% —
24 CITADEL ADVISORS LLC 0.00% of their portfolio MIAMI, FL 166,130166.1k $457.0k $457.0k 0.00% —
25 RHUMBLINE ADVISERS 0.00% of their portfolio BOSTON, MA 132,596132.6k $365.0k $365.0k 0.00% —
26 D. E. Shaw & Co., Inc. 0.00% of their portfolio New York, NY 119,373119.4k $328.0k $328.0k 0.00% —
27 GENERAL AMERICAN INVESTORS CO INC 0.03% of their portfolio NEW YORK, NY 119,250119.2k $328.0k $328.0k 0.03% —
28 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 107,756107.8k $297.0k $297.0k 0.00% —
29 CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio WEST SACRAMENTO, CA 107,744107.7k $296.0k $296.0k 0.00% —
30 D.A. DAVIDSON & CO. 0.00% of their portfolio GREAT FALLS, MT 105,000105.0k $289.0k $289.0k 0.00% —
31 Cubist Systematic Strategies, LLC 0.00% of their portfolio STAMFORD, CT 98,30598.3k $270.0k $270.0k 0.00% —
32 SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio BALA CYNWYD, PA 80,76180.8k $222.0k $222.0k 0.00% —
33 NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio ALBANY, NY 65,20065.2k $179.0k $179.0k 0.00% —
34 Westchester Capital Management, LLC 0.01% of their portfolio VALHALLA, NY 64,96465.0k $179.0k $179.0k 0.01% —
35 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 58,30158.3k $160.0k $160.0k 0.00% —
36 UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio NEW YORK, NY 57,40057.4k $157.8k $157.8k 0.00% —
37 CREDIT SUISSE AG/ 0.00% of their portfolio ZURICH, V8 54,25254.3k $149.0k $149.0k 0.00% —
38 MetLife Investment Management, LLC 0.00% of their portfolio Whippany, NJ 53,60753.6k $147.4k $147.4k 0.00% —
39 Raymond James Financial Services Advisors, Inc. 0.00% of their portfolio ST. PETERSBURG, FL 51,34351.3k $141.0k $141.0k 0.00% —
40 INTREPID FAMILY OFFICE LLC 0.42% of their portfolio SARASOTA, FL 50,00050.0k $138.0k $138.0k 0.42% —
41 GSA CAPITAL PARTNERS LLP 0.02% of their portfolio LONDON, X0 44,74244.7k $123.0k $123.0k 0.02% —
42 PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio BALTIMORE, MD 44,31344.3k $122.0k $122.0k 0.00% —
43 JANUS HENDERSON GROUP PLC 0.00% of their portfolio LONDON, X0 44,08844.1k $120.0k $120.0k 0.00% —
44 AMERICAN INTERNATIONAL GROUP, INC. 0.00% of their portfolio New York, NY 43,36343.4k $119.0k $119.0k 0.00% —
45 Invesco Ltd. 0.00% of their portfolio ATLANTA, GA 41,51641.5k $114.0k $114.0k 0.00% —
46 DEUTSCHE BANK AG\ 0.00% of their portfolio FRANKFURT AM MAIN, 2M 37,08437.1k $102.0k $102.0k 0.00% —
47 Red Wave Investments LLC 0.04% of their portfolio DILLSBURG, PA 37,00037.0k $102.0k $102.0k 0.04% —
48 MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio Toronto, A6 35,76535.8k $98.4k $98.4k 0.00% —
49 VOYA INVESTMENT MANAGEMENT LLC 0.00% of their portfolio ATLANTA, GA 34,71534.7k $95.5k $95.5k 0.00% —
50 Legal & General Group Plc 0.00% of their portfolio London, X0 31,81731.8k $87.0k $87.0k 0.00% —
51 SG Americas Securities, LLC 0.00% of their portfolio NEW YORK, NY 31,20431.2k $86.0k $86.0k 0.00% —
52 Cambridge Investment Research Advisors, Inc. 0.00% of their portfolio FAIRFIELD, IA 28,07328.1k $77.0k $77.0k 0.00% —
53 Guidance Point Advisors, LLC 0.03% of their portfolio Wellesley, MA 25,74225.7k $70.0k $70.0k 0.03% —
54 Zurcher Kantonalbank (Zurich Cantonalbank) 0.00% of their portfolio ZURICH, V8 24,41724.4k $67.0k $67.0k 0.00% —
55 Round Rock Advisors LLC 0.03% of their portfolio WILTON, CT 24,03524.0k $66.0k $66.0k 0.03% —
56 PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio DES MOINES, IA 23,08423.1k $63.0k $63.0k 0.00% —
57 ARIZONA STATE RETIREMENT SYSTEM 0.00% of their portfolio PHOENIX, AZ 22,64122.6k $62.0k $62.0k 0.00% —
58 Mutual Advisors, LLC 0.00% of their portfolio OMAHA, NE 21,43921.4k $59.0k $59.0k 0.00% —
59 STRS OHIO 0.00% of their portfolio COLUMBUS, OH 21,30021.3k $58.0k $58.0k 0.00% —
60 ProShare Advisors LLC 0.00% of their portfolio BETHESDA, MD 20,11320.1k $56.0k $56.0k 0.00% —
61 ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio NASHVILLE, TN 19,70019.7k $54.0k $54.0k 0.00% —
62 WELLS FARGO & COMPANY/MN 0.00% of their portfolio SAN FRANCISCO, CA 18,54818.5k $51.0k $51.0k 0.00% —
63 STATE OF WISCONSIN INVESTMENT BOARD 0.00% of their portfolio MADISON, WI 15,54115.5k $43.0k $43.0k 0.00% —
64 Flagship Private Wealth, LLC 0.04% of their portfolio Woburn, MA 14,15814.2k $39.0k $39.0k 0.04% —
65 Procyon Advisors, LLC 0.01% of their portfolio SHELTON, CT 13,67113.7k $38.0k $38.0k 0.01% —
66 BANK OF AMERICA CORP /DE/ 0.00% of their portfolio CHARLOTTE, NC 13,03913.0k $35.0k $35.0k 0.00% —
67 Abacus Planning Group, Inc. 0.01% of their portfolio COLUMBIA, SC 12,51012.5k $34.0k $34.0k 0.01% —
68 Virtu Financial LLC 0.00% of their portfolio New York, NY 12,50912.5k $34.0k $34.0k 0.00% —
69 TWO SIGMA SECURITIES, LLC 0.00% of their portfolio NEW YORK, NY 11,98312.0k $33.0k $33.0k 0.00% —
70 TEACHER RETIREMENT SYSTEM OF TEXAS 0.00% of their portfolio AUSTIN, TX 11,80111.8k $32.0k $32.0k 0.00% —
71 AMALGAMATED BANK 0.00% of their portfolio NEW YORK, NY 11,56811.6k $32.0k $32.0k 0.00% —
72 JANE STREET GROUP, LLC 0.00% of their portfolio NEW YORK, NY 11,45511.5k $31.0k $31.0k 0.00% —
73 Tower Research Capital LLC (TRC) 0.00% of their portfolio NEW YORK, NY 11,31211.3k $32.0k $32.0k 0.00% —
74 FSA Wealth Management LLC 0.02% of their portfolio Needham, MA 11,15011.2k $31.0k $31.0k 0.02% —
75 MTM Investment Management, LLC 0.02% of their portfolio SPARTANBURG, SC 10,90010.9k $30.0k $30.0k 0.02% —
76 VICTORY CAPITAL MANAGEMENT INC 0.00% of their portfolio San Antonio, TX 10,44110.4k $29.0k $29.0k 0.00% —
77 UBS Group AG 0.00% of their portfolio ZURICH, V8 7,7137.7k $22.0k $22.0k 0.00% —
78 Leonteq Securities AG 0.00% of their portfolio ZURICH, V8 7,5007.5k $20.6k $20.6k 0.00% —
79 Allspring Global Investments Holdings, LLC 0.00% of their portfolio CHARLOTTE, NC 7,0157.0k $19.0k $19.0k 0.00% —
80 Ameritas Investment Partners, Inc. 0.00% of their portfolio LINCOLN, NE 6,8506.8k $18.0k $18.0k 0.00% —
81 Metropolitan Life Insurance Co/NY 0.00% of their portfolio New York, NY 6,2226.2k $17.1k $17.1k 0.00% —
82 CITIGROUP INC 0.00% of their portfolio NEW YORK, NY 4,7614.8k $13.0k $13.0k 0.00% —
83 FMR LLC 0.00% of their portfolio BOSTON, MA 4,6544.7k $13.0k $13.0k 0.00% —
84 OSAIC HOLDINGS, INC. 0.00% of their portfolio SCOTTSDALE, AZ 2,9703.0k $8.0k $8.0k 0.00% —
85 TD Waterhouse Canada Inc. 0.00% of their portfolio TORONTO, A6 2,0252.0k $5.6k $5.6k 0.00% —
86 WOLFF WIESE MAGANA LLC 0.00% of their portfolio CARSLBAD, CA 1,2001.2k $3.0k $3.0k 0.00% —
87 China Universal Asset Management Co., Ltd. 0.00% of their portfolio SHANGHAI, F4 1,1191.1k $3.0k $3.0k 0.00% —
88 ROYAL BANK OF CANADA 0.00% of their portfolio TORONTO, A6 1,1121.1k $3.0k $3.0k 0.00% —
89 IFP Advisors, Inc 0.00% of their portfolio TAMPA, FL 900900 $9.0k $9.0k 0.00% —
90 Global Trust Asset Management, LLC 0.00% of their portfolio PALM BEACH GARDENS, FL 855855 $2.0k $2.0k 0.00% —
91 US BANCORP \DE\ 0.00% of their portfolio MINNEAPOLIS, MN 800800 $2.0k $2.0k 0.00% —
92 Johnson Midwest Financial, LLC 0.01% of their portfolio GLIDDEN, IA 770770 $2.0k $2.0k 0.01% —
93 FIRST MANHATTAN CO. LLC. 0.00% of their portfolio NEW YORK, NY 600600 $1.0k $1.0k 0.00% —
94 American Portfolios Advisors 0.00% of their portfolio HOLBROOK, NY 450450 $1.2k $1.2k 0.00% —
95 CWM, LLC 0.00% of their portfolio OMAHA, NE 407407 $1.0k $1.0k 0.00% —
96 Clearstead Advisors, LLC 0.00% of their portfolio CLEVELAND, OH 400400 $1.0k $1.0k 0.00% —
97 Daiwa Securities Group Inc. 0.00% of their portfolio CHIYODA-KU,TOKYO, M0 343343 $1.0k $1.0k 0.00% —
98 Cutler Group LLC / CA 0.00% of their portfolio SAN FRANCISCO, CA 300300 $0 $0 0.00% —
99 Eagle Bay Advisors LLC 0.00% of their portfolio NEW YORK, NY 277277 $1.0k $1.0k 0.00% —
100 Glassman Wealth Services 0.00% of their portfolio VIENNA, VA 143143 $0 $0 0.00% —