QUANTUM SI INC QSI
COM CL A · Common Stock · CUSIP 74765K105 · ISIN US74765K1051
- SectorTechnology
- IndustryMeasuring & Controlling Devices, NEC
- HeadquartersBranford, CT
- FilingsSEC EDGAR
* 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.
| Holder | Stake |
|---|---|
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% |
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)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q4 2020 | 0 | — | 0 | — | — |
| Q1 2021 | 0 | — | 0 | — | — |
| Q2 2021 | 0 | — | 0 | — | — |
| Q3 2021 | 0 | — | 0 | — | — |
| Q4 2021 | 0 | — | 0 | — | — |
| Q1 2022 | 0 | — | 4 | $1.2m | — |
| Q2 2022 | 1 | $79.2k | 2 | $10.5k | — |
| Q3 2022 | 1 | $78.6k | 0 | — | — |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2022-08-17 | LaPointe Christian General Counsel & Corp. Secr. | Bought | $78.6k20.0k shares |
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
| Manager | Shares | Change |
|---|---|---|
| ARK Investment Management LLC 0.25% of their portfolio | 13.2m $36.4m | — |
| BlackRock Inc. 0.00% of their portfolio | 6.4m $17.5m | — |
| GLENVIEW CAPITAL MANAGEMENT, LLC 0.36% of their portfolio | 5.1m $14.0m | — |
| VANGUARD GROUP INC 0.00% of their portfolio | 4.9m $13.5m | — |
| Foresite Capital Management IV, LLC 1.57% of their portfolio | 1.8m $4.9m | — |
| STATE STREET CORP 0.00% of their portfolio | 1.7m $4.7m | — |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 1.6m $4.4m | — |
| DEERFIELD MANAGEMENT COMPANY, L.P. 0.08% of their portfolio | 1.4m $3.9m | — |
| Sumitomo Mitsui Trust Group, Inc. 0.00% of their portfolio | 1.3m $3.5m | — |
| Amova Asset Management Americas, Inc. 0.04% of their portfolio | 1.3m $3.4m | — |
| Foresite Capital Management V, LLC 1.95% of their portfolio | 924.4k $2.5m | — |
| NORTHERN TRUST CORP 0.00% of their portfolio | 772.6k $2.1m | — |
| Fosun International Ltd 0.22% of their portfolio | 743.9k $2.0m | — |
| GUGGENHEIM CAPITAL LLC 0.02% of their portfolio | 678.7k $1.9m | — |
| Rubric Capital Management LP 0.09% of their portfolio | 672.4k $1.8m | — |
| Foresite Capital Opportunity Management V, LLC 5.23% of their portfolio | 633.6k $1.7m | — |
| Neumann Advisory Hong Kong Ltd 0.41% of their portfolio | 427.6k $1.2m | — |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 396.1k $1.1m | — |
| Nuveen Asset Management, LLC 0.00% of their portfolio | 365.4k $1.0m | — |
| Bank of New York Mellon Corp 0.00% of their portfolio | 276.0k $759.0k | — |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 233.0k $641.0k | — |
| Clearline Capital LP 0.08% of their portfolio | 211.9k $583.0k | — |
| Swiss National Bank 0.00% of their portfolio | 194.5k $535.0k | — |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 166.1k $457.0k | — |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 132.6k $365.0k | — |
| D. E. Shaw & Co., Inc. 0.00% of their portfolio | 119.4k $328.0k | — |
| GENERAL AMERICAN INVESTORS CO INC 0.03% of their portfolio | 119.2k $328.0k | — |
| MORGAN STANLEY 0.00% of their portfolio | 107.8k $297.0k | — |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 107.7k $296.0k | — |
| D.A. DAVIDSON & CO. 0.00% of their portfolio | 105.0k $289.0k | — |
| Cubist Systematic Strategies, LLC 0.00% of their portfolio | 98.3k $270.0k | — |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 80.8k $222.0k | — |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 65.2k $179.0k | — |
| Westchester Capital Management, LLC 0.01% of their portfolio | 65.0k $179.0k | — |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 58.3k $160.0k | — |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC 0.00% of their portfolio | 57.4k $157.8k | — |
| CREDIT SUISSE AG/ 0.00% of their portfolio | 54.3k $149.0k | — |
| MetLife Investment Management, LLC 0.00% of their portfolio | 53.6k $147.4k | — |
| Raymond James Financial Services Advisors, Inc. 0.00% of their portfolio | 51.3k $141.0k | — |
| INTREPID FAMILY OFFICE LLC 0.42% of their portfolio | 50.0k $138.0k | — |
| GSA CAPITAL PARTNERS LLP 0.02% of their portfolio | 44.7k $123.0k | — |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 44.3k $122.0k | — |
| JANUS HENDERSON GROUP PLC 0.00% of their portfolio | 44.1k $120.0k | — |
| AMERICAN INTERNATIONAL GROUP, INC. 0.00% of their portfolio | 43.4k $119.0k | — |
| Invesco Ltd. 0.00% of their portfolio | 41.5k $114.0k | — |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 37.1k $102.0k | — |
| Red Wave Investments LLC 0.04% of their portfolio | 37.0k $102.0k | — |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio | 35.8k $98.4k | — |
| VOYA INVESTMENT MANAGEMENT LLC 0.00% of their portfolio | 34.7k $95.5k | — |
| Legal & General Group Plc 0.00% of their portfolio | 31.8k $87.0k | — |
| SG Americas Securities, LLC 0.00% of their portfolio | 31.2k $86.0k | — |
| Cambridge Investment Research Advisors, Inc. 0.00% of their portfolio | 28.1k $77.0k | — |
| Guidance Point Advisors, LLC 0.03% of their portfolio | 25.7k $70.0k | — |
| Zurcher Kantonalbank (Zurich Cantonalbank) 0.00% of their portfolio | 24.4k $67.0k | — |
| Round Rock Advisors LLC 0.03% of their portfolio | 24.0k $66.0k | — |
| PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio | 23.1k $63.0k | — |
| ARIZONA STATE RETIREMENT SYSTEM 0.00% of their portfolio | 22.6k $62.0k | — |
| Mutual Advisors, LLC 0.00% of their portfolio | 21.4k $59.0k | — |
| STRS OHIO 0.00% of their portfolio | 21.3k $58.0k | — |
| ProShare Advisors LLC 0.00% of their portfolio | 20.1k $56.0k | — |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 19.7k $54.0k | — |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 18.5k $51.0k | — |
| STATE OF WISCONSIN INVESTMENT BOARD 0.00% of their portfolio | 15.5k $43.0k | — |
| Flagship Private Wealth, LLC 0.04% of their portfolio | 14.2k $39.0k | — |
| Procyon Advisors, LLC 0.01% of their portfolio | 13.7k $38.0k | — |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 13.0k $35.0k | — |
| Abacus Planning Group, Inc. 0.01% of their portfolio | 12.5k $34.0k | — |
| Virtu Financial LLC 0.00% of their portfolio | 12.5k $34.0k | — |
| TWO SIGMA SECURITIES, LLC 0.00% of their portfolio | 12.0k $33.0k | — |
| TEACHER RETIREMENT SYSTEM OF TEXAS 0.00% of their portfolio | 11.8k $32.0k | — |
| AMALGAMATED BANK 0.00% of their portfolio | 11.6k $32.0k | — |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 11.5k $31.0k | — |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 11.3k $32.0k | — |
| FSA Wealth Management LLC 0.02% of their portfolio | 11.2k $31.0k | — |
| MTM Investment Management, LLC 0.02% of their portfolio | 10.9k $30.0k | — |
| VICTORY CAPITAL MANAGEMENT INC 0.00% of their portfolio | 10.4k $29.0k | — |
| UBS Group AG 0.00% of their portfolio | 7.7k $22.0k | — |
| Leonteq Securities AG 0.00% of their portfolio | 7.5k $20.6k | — |
| Allspring Global Investments Holdings, LLC 0.00% of their portfolio | 7.0k $19.0k | — |
| Ameritas Investment Partners, Inc. 0.00% of their portfolio | 6.8k $18.0k | — |
| Metropolitan Life Insurance Co/NY 0.00% of their portfolio | 6.2k $17.1k | — |
| CITIGROUP INC 0.00% of their portfolio | 4.8k $13.0k | — |
| FMR LLC 0.00% of their portfolio | 4.7k $13.0k | — |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 3.0k $8.0k | — |
| TD Waterhouse Canada Inc. 0.00% of their portfolio | 2.0k $5.6k | — |
| WOLFF WIESE MAGANA LLC 0.00% of their portfolio | 1.2k $3.0k | — |
| China Universal Asset Management Co., Ltd. 0.00% of their portfolio | 1.1k $3.0k | — |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 1.1k $3.0k | — |
| IFP Advisors, Inc 0.00% of their portfolio | 900 $9.0k | — |
| Global Trust Asset Management, LLC 0.00% of their portfolio | 855 $2.0k | — |
| US BANCORP \DE\ 0.00% of their portfolio | 800 $2.0k | — |
| Johnson Midwest Financial, LLC 0.01% of their portfolio | 770 $2.0k | — |
| FIRST MANHATTAN CO. LLC. 0.00% of their portfolio | 600 $1.0k | — |
| American Portfolios Advisors 0.00% of their portfolio | 450 $1.2k | — |
| CWM, LLC 0.00% of their portfolio | 407 $1.0k | — |
| Clearstead Advisors, LLC 0.00% of their portfolio | 400 $1.0k | — |
| Daiwa Securities Group Inc. 0.00% of their portfolio | 343 $1.0k | — |
| Cutler Group LLC / CA 0.00% of their portfolio | 300 $0 | — |
| Eagle Bay Advisors LLC 0.00% of their portfolio | 277 $1.0k | — |
| Glassman Wealth Services 0.00% of their portfolio | 143 $0 | — |