Quantum-Si Incorporated filings document the formal disclosures of a Nasdaq-listed proteomics technology company developing single-molecule protein sequencing systems. Form 8-K reports furnish financial results, business updates, Regulation FD presentations and material agreements tied to the company’s operations and capital markets activity.
The filing record also covers annual-meeting proxy matters, board and compensation governance, executive and equity-award disclosure, Class A common stock, and redeemable warrants listed under QSIAW. Material-event filings document sales-agreement and shelf-registration disclosures for potential Class A common stock issuance, as well as lease-related settlement and termination matters.
Quantum-Si (QSI) reported third-quarter 2026 revenue of $212,000, down 61.6%; nine-month revenue was $814,000, down 59.0%. Net loss was $22.316 million and $67.521 million for those periods, versus $35.703 million and $83.728 million a year earlier. Lower instrument and consumables sales, as customers deferred purchases ahead of Proteus, primarily drove revenue declines; Proteus launch is estimated for the second quarter of 2027. Cash, cash equivalents and marketable securities were $149.4 million as of September 30, 2026; management believes these resources plus product and service revenue can fund operations for at least the next 12 months from issuance.
In August, Quantum-Si terminated approximately 20% of its 152 employee workforce in a restructuring, recognizing approximately $2.6 million in cash severance and other benefits and $0.1 million of noncash stock-option modification expense; completion is expected by the end of the fourth quarter of 2026. On October 30, Quantum-Si and Sterling City Science South Development, LLC mutually terminated an uncommenced San Diego lease, releasing approximately $38.3 million in aggregate minimum cash payments. The landlord is required to pay approximately $1.3 million and facilitate return and cancellation of an approximately $2.1 million letter of credit. The termination is a nonrecognized subsequent event; the company expects no material impact on operating results.
Quantum-Si reported third-quarter 2026 revenue of $212,000, compared with $552,000 a year earlier, as it transitions from Platinum to anticipated Proteus. Net loss narrowed to $22.3 million from $35.7 million, and adjusted EBITDA loss narrowed to $17.0 million from $20.1 million. For the nine months, revenue was $814,000 versus $2.0 million, and net loss was $67.5 million versus $83.7 million.
Cash, cash equivalents and marketable securities were $149.4 million as of September 30, 2026; based on its current operating plan and cost-reduction actions, the company expects these resources to fund operations into the fourth quarter of 2028. Full-year 2026 guidance is approximately $1.0 million in revenue, adjusted total operating expenses of $87.0 million or less (previously $98.0 million or less), and total cash usage of $87.0 million or less (previously $93.0 million or less). The third-quarter reduction in force affected approximately 20% of total company headcount; the company expects approximately $12 million in annual operating expense savings. Proteus remains on track for an anticipated Q2 2027 commercial launch, and its pre-order program has launched.
Quantum-Si Incorporated (QSI) regained compliance with Nasdaq’s minimum bid price requirement, with Nasdaq notifying the company on October 14, 2026 that compliance had been restored as of October 13, 2026. Nasdaq said the closing bid price had been at or above $1.00 per share for at least 10 consecutive business days, and the matter is closed. The company said it will continue to monitor the price; a future failure to meet the requirement is likely to prompt another notice that its shares are subject to delisting.
Quantum-Si demonstrated detection of 19 amino acids in its Proteus development program. It is working to deploy the capability into a developmental sequencing kit for routine use on integrated Proteus instruments. The company said it remains confident in demonstrating detection of all 20 amino acids by year-end 2026; deployment into the kit is underway.
At the 2026 World HUPO Congress, Quantum-Si presented Proteus results from a developmental kit detecting 18 amino acids, which it said showed significant improvements across every key measure of sequencing performance. The company expects the 19-amino-acid capability, once deployed in a kit, to further increase Proteus sequencing performance. It said this progress strengthens its confidence in advancing the platform toward commercial launch in the second quarter of 2027.
Quantum-Si Inc. (QSI) reported interim development results comparing its Proteus platform with commercially available Platinum Pro. In a control-peptide study, Proteus produced a median of 30 times more reported alignments per single-chamber run and a median false discovery rate of 1.36%, versus 6.58% for Platinum Pro. In protein-mixture tests, Proteus identified 1.6–2.0 times more peptides; in a 24-protein panel, it detected 24 proteins versus Platinum Pro’s average of 20.3 and 269,864 amino acids versus 63,366.
QSI said the instrument, consumable, loading protocol and analysis software remain in development and are not fully optimized; the developmental kit used detects 18 amino acids. QSI projected that a full four-chamber Proteus run could deliver approximately 60 times more alignments than a two-chamber Platinum Pro run, based on single-chamber results and the assumption that each chamber performs like its single-chamber median. Proteus launch is on track for Q2 2027.
Quantum-Si Inc President & CEO Jeffrey Alan Hawkins reported direct sales of 20,143 Class A common shares on September 21, 2026, at a weighted average price of $0.7558 per share, and 9,709 shares on September 22 at a weighted average price of $0.7608 per share. The sales were mandatory sell-to-cover transactions for required tax withholding when previously granted restricted stock units vested; the footnote says he could not alter the provision.
Quantum-Si Inc. (QSI) Chief Financial Officer Jeffry R. Keyes reported selling 5,172 Class A common shares on September 21, 2026, at a weighted average price of $0.7558 per share, and 2,493 shares on September 22 at $0.7608 per share. Both sales were made under a mandatory sell-to-cover provision for required federal, state and local withholding taxes tied to vesting of previously granted restricted stock units. The provision could not be altered, and no Rule 10b5-1 plan is reported.
Quantum-Si Inc. GC & Corp. Secretary Christian LaPointe reported selling 9,795 Class A shares on September 21, 2026, at a weighted average $0.7558 per share, and 4,721 shares on September 22, 2026, at a weighted average $0.7608. Both sales were under a mandatory sell-to-cover provision for required withholding taxes on previously granted restricted stock units; LaPointe could not alter the provision. No Rule 10b5-1 plan is reported.
Quantum-Si Inc. (QSI) Class A common stock is the subject of an intended sale by Jeffrey Alan Hawkins, identified as an officer and director: 29,852 shares, with an aggregate market value of $22,610.69 and an approximate sale date of September 21, 2026. The transaction is described as covering tax withholding on 59,609 shares from restricted stock unit vesting on September 20, 2026. The issuer required the sell-to-cover transaction, which is described as not discretionary for the reporting person.
Quantum-Si Inc. officer Christian LaPointe reported a proposed sale of 14,516 shares of Class A common stock, with an aggregate market value of $10,994.80 and an approximate sale date of September 21, 2026. The reported broker is Morgan Stanley Smith Barney LLC.
The notice also records 60,424 shares acquired through restricted stock unit vesting on September 20, 2026. The remarks say Quantum-Si's election required a sell-to-cover transaction for tax withholding and that the sale was not a discretionary trade by LaPointe.