Quantum-Si (QSI) Q3 2026 earnings review
Quantum-Si cuts its cash burn, while legacy sales shrink
Quantum-Si cut its quarterly spending while preparing its next-generation protein analyzer for a 2027 launch, though legacy device sales nearly stopped. Third-quarter revenue dropped 62% from a year ago to $212,000 as customers waited for the new Proteus machine. Following a 20% staff reduction in August, finance chief Jeff Keyes lowered the full-year ceiling for operating costs excluding one-offs by $11 million and cut the cash usage ceiling by $6 million.
| Revenue | $212K -62% from a year ago |
|---|---|
| Operating costs, excluding one-offs | $18.2M -19% from last quarter |
| Cash and marketable securities | $149.4M $20.5M used in the quarter |
| Full-year cost and cash outlook | Lowered Expenses cut $11M; cash use cut $6M |
⚖️ Verdict: 🟢 Bullish
The story got better because the August layoffs immediately lowered operating costs without slowing down key lab milestones for Proteus. Chief executive Jeff Hawkins said the team fixed earlier machine consistency problems, detected 19 of the 20 amino acids needed for launch, and opened a pre-order program. One caution: the company disclosed zero pre-orders, and global part shortages forced it to pay suppliers early, keeping quarterly cash burn near $20 million.
The question now is whether lab progress and roadshow interest will turn into paid orders and lower cash burn in 2027. Either early-access machines perform well enough in customer labs to bring in deposits and stretch the $149 million cash pile to late 2028, or slow adoption and advance part buying force another cash crunch. Disclosed pre-order counts and the placement of test machines at customer sites in early 2027 will decide it.
🐂 Bull Case
Job Cuts Lowered the Expense Ceiling by $11 Million
Quantum-Si cut about 20% of its staff in August to align its spending with the delayed launch of Proteus, its next-generation protein sequencing machine. Chief executive Jeff Hawkins said those cuts "have not adversely impacted Proteus development" and will save $12 million a year. In the third quarter, operating expenses excluding one-offs fell 19.3% from the second quarter to $18.2 million.
- Research and development: $13.8 million, down 0.7% from a year ago and down 12.9% from last quarter
- Selling, general and administrative: $10.1 million, down 5.9% from a year ago
- Restructuring charges: $2.9 million in the third quarter for severance costs
- Full-year operating expense ceiling, excluding one-offs: cut by $11.0 million to $87.0 million or less
Headline operating expenses dropped 40.3% from a year ago, but that comparison laps $15.4 million of one-time lease exit and legal settlement charges in the third quarter of 2025. Stripping out one-offs in both years, underlying operating costs fell 13.8% by our math. Finance chief Jeff Keyes also lowered the full-year cash usage ceiling by $6.0 million to $87.0 million.
What to watch: fourth-quarter operating expenses excluding one-offs. A reading near $18 million would confirm the full quarterly benefit of the layoffs and leave full-year spending nearly $7 million below the new ceiling.
Amino Acid Coverage Reached 19 of 20 With Higher Output
Proteins are built from 20 standard amino acids, and researchers want a machine that can read all 20 before they buy it. During the quarter, Quantum-Si's chemical recognizers detected 19 amino acids in lab tests, up from 15 at the end of 2025. The proteomics firm also packed 18 of them into a developmental test kit and plans to finish technology work on specialized sample preparation kits by year-end.
Using that 18-amino-acid kit and artificial intelligence software at the World HUPO conference in September, a prototype Proteus machine generated about 30 times more sequencing output per chamber than the current Platinum Pro device. It also cut the false discovery rate — the share of protein reads that are wrong — from 6.58% on Platinum Pro to 1.36%.
What to watch: detection of the 20th amino acid before the end of 2026. Hitting that target on time is required to include all 20 in the commercial launch kit by the second quarter of 2027.
🐻 Bear Case
Cash Runway to Late 2028 Still Needs a Post-Launch Burn Drop
Quantum-Si ended September with $149.4 million in cash and marketable securities after burning $20.5 million in the third quarter, matching the second quarter's $20.5 million outflow. The company regained compliance with Nasdaq's minimum share price rule in October, which removes an immediate listing concern, and Keyes reiterated that existing cash will fund operations into the fourth quarter of 2028.
That runway math remains tight because severance payments and early parts purchases offset the initial layoff savings. By our math, the $87.0 million full-year cash usage ceiling leaves at least $128.8 million at the end of 2026. Stretching $128.8 million across the eight quarters of 2027 and 2028 allows an average quarterly burn of only $16.1 million, down from $22.1 million a quarter across the first nine months of 2026.
What to watch: year-end cash and marketable securities on the fourth-quarter balance sheet. A balance near or above $130 million would show the cost cuts are slowing the cash drain ahead of the 2027 launch.
Pre-Orders Have No Numbers While Legacy Sales Shrink 62%
To turn conference interest into sales for its $425,000 Proteus machine, Quantum-Si opened a pre-order program after holding roadshows in more than 35 cities for over 800 attendees. Customers can now "place an order now with a deposit" to get priority delivery and preferred pricing, Hawkins said. Yet the company did not report a single pre-order or dollar of deposits.
Meanwhile, waiting for Proteus continues to freeze purchases of the older Platinum line. Third-quarter revenue fell 61.6% from a year ago and 38.4% from the second quarter to $212,000, with product sales down 65.7% to $173,000. Hawkins noted that roadshow attendees still want to test the machine on their own biological samples before committing, and sample testing has not opened yet.
What to watch: disclosed pre-order counts or customer deposit balances on the fourth-quarter call in March. Without signed orders, the 2027 commercial ramp rests on unweighted customer interest.
Proteus Hardware Fixes Remain Unproven Outside the Lab
Last quarter, Quantum-Si delayed the Proteus launch by two quarters to the second quarter of 2027 to add an extra hardware design cycle. This quarter, Hawkins said the team has "substantially addressed the instrument variability issues identified earlier in development" and was able to "significantly limit the number of design changes required relative to our original expectations".
That progress argues against another immediate delay, and the company finished the design work and ordered parts for the new build. However, the redesigned machines have not arrived yet; they will reach Quantum-Si in the fourth quarter and go straight to internal research labs rather than customer inventory. Hawkins also kept a caveat on the variability fix "because you can always get a surprise or 2".
What to watch: placement of the first early-access Proteus machines into external customer labs in early 2027. External placements will prove the redesigned hardware works outside Quantum-Si's own building.
👓 Other Themes
AI Supply Chain Bottlenecks Force Early Part Buying
Global demand for artificial intelligence hardware is stretching delivery times for standard electronics and raw materials used in Proteus. To prevent a launch delay in the second quarter of 2027, Keyes said the company is "placing orders earlier, committing volume with key suppliers" and building safety stock. That early buying lifted prepaid expenses 56.2% since December to $7.1 million, tying up cash earlier than planned.
💲 Other KPIs
Gross margin — the share of sales left after the direct cost of making products and delivering services — dropped to 35.0% ($74,000) from 50.0% ($172,000) in the second quarter, matching the 35.1% recorded a year ago. Nine-month gross margin fell to 39.3% from 51.9% last year as hardware sales slowed and trade-in programs weighed on pricing.
On-hand inventory fell 48.7% from December and 19.1% from June to $1.64 million as the company worked down older Platinum stock. At the same time, prepaid expenses — advance payments to suppliers before goods arrive — climbed 56.2% from December to $7.12 million as the firm locked in long-lead components for Proteus.
The average share count rose 4.8% from a year ago and 0.5% from the second quarter to 219.0 million. Annual share growth slowed sharply from 18.6% in the second quarter because the company lapped its July 2025 stock offering and did not sell new equity during the third quarter.
🔮 Guidance
Unchanged. The full-year plan still calls for revenue to fall about 59% from 2025's $2.44 million as sales reps focus on Proteus rather than Platinum. With $814,000 booked in the first nine months, the target leaves about $186,000 for the fourth quarter by our math, down 12.3% from the third quarter and down 58.8% from a year ago.
Lowered by $11.0 million (a positive revision for expenses). The new ceiling leaves full-year spending nearly flat (+0.8% at the top end) against $86.3 million in 2025. By our math, after $62.1 million in the first nine months, the ceiling allows up to $24.9 million in the fourth quarter, well above the third quarter's $18.2 million run-rate.
Lowered by $6.0 million. Management reduced its maximum full-year cash drain after the August job cuts, though advance supplier payments absorbed part of the operating expense savings. By our math, subtracting $66.4 million of nine-month cash and securities usage leaves at most $20.6 million of burn for the fourth quarter, right in line with the third quarter's $20.5 million.
❓ Key Questions
How many Proteus pre-orders and deposits have customers placed?
Quantum-Si launched a formal pre-order program requiring a cash deposit to secure priority delivery for its $425,000 machine, but gave no order numbers. Disclosing actual deposits would show whether roadshow attendance is turning into committed demand.
When will outside researchers be able to submit biological samples?
Chief executive Jeff Hawkins said prospective buyers want to see sequencing data generated from their own biological samples before buying a machine. Management has not given a date for opening external sample testing ahead of the second-quarter 2027 launch.
How much will research spending drop after Proteus launches?
Reaching the fourth quarter of 2028 on existing cash requires average quarterly burn to fall from $20.5 million today to about $16.1 million across 2027 and 2028 by our math. Management has not quantified how much research spending will wind down after launch.
How much cash will early component orders tie up in 2027?
To beat supply chain bottlenecks caused by artificial intelligence demand, Quantum-Si is ordering parts and consumables well past the initial launch window. Investors need to know how many millions of dollars this safety stock will absorb from the 2027 cash budget.