$1.24
−4.42%Price chart
Oct 6Oct 9Oct 14Oct 19Oct 22Oct 27Oct 30Nov 4
Key dataNov 4, 2026
Open$1.32
From 52W high−32.47%
Volume3.59M
Market cap$271.99M
P/E (TTM)—
P/S (TTM)169.5x
Div yield—
Key dataNov 4, 2026
Open
$1.32
From 52W high
−32.47%
Volume
3.59M
Market cap
$271.99M
ValuationView details →
P/E (Fwd)
—
EV/EBITDA
−1.8x
P/E (TTM)
—
RSI (14)
48.1
MomentumView details →
1D Return
−4.42%
YTD Return
+12.05%
SummaryUpdated Jun 1, 2026
Quantum-Si Incorporated (NASDAQ:QSI) is a biotechnology company founded in 2013 and headquartered in Guilford, Connecticut. The company went public in November 2020 through a SPAC merger. Quantum-Si has developed what it claims to be the world's first single-molecule protein sequencing platform, representing a breakthrough in proteomics research. The company transitioned from a pre-revenue research and development stage to commercial operations in late 2022 with the launch of its flagship Platinum protein sequencing system. As of 2025, Quantum-Si is in the early stages of commercializing its technology across academic, biotechnology, and pharmaceutical markets globally.
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Latest newsMore news →
Quantum-Si announced a targeted workforce reduction of about 20% to lower cash burn and fund the revised development timeline.83d agoQuantum-Si moved the planned launch of its Proteus protein sequencing platform to Q2 2027 from end of 2026, citing the need for an additional integrated instrument design cycle before production.83d agoQuantum-Si Incorporated reported a Q2 loss of $0.11 per share, beating the Zacks Consensus Estimate of a $0.13 loss and improving from a $0.16 loss a year ago.83d ago