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How to Buy Quantum-Si Incorporated Class A Common Stock (QSI) Stock

Compare 15 brokers offering QSI, check which offer overnight sessions, see options pricing, and confirm OTC tier access.

QSI
$0.7452−$0.0248 (−3.22%)
Day range
$0.7420 – $0.8010
52-week range
$0.6900 – $3.10
Volume
1.26M
Market cap
$163.09M
Exchange
XNAS
Asset class
common
Optionable
Yes
24-hour trading
7 brokers — verify symbol
Fractional shares
9 brokers — verify symbol
Tokenized
No
Market cap tier
micro

Where to buy QSI

15 brokers in our matrix offer QSI (penny/OTC-friendly subset). Verify availability and current fees with each broker before trading.

BrokerCommissionFractionalExtendedOvernightOptionsOTCQXOTCQBPink Cur.Pink Ltd.GreySurchargeShort locate
Firstrade logoFirstradeReview$0
~4,000+ tickers, ≥ $5
~1,200
$0FullFullFullFullLimited—limited
Interactive Brokers logoInteractive BrokersReview$0 (Lite) / per-share (Pro)
~10,000
per-contract pricingFullFullFullFullFullPer-share pricing appliesbest
TradeStation logoTradeStationReview$0 listed
$0.50 / $0.60FullFullFullFullLimited$0.005/share OTC (TS Select/TS Go), $0 up to 10,000 sharesstrong
Charles Schwab (thinkorswim) logoCharles Schwab (thinkorswim)Review$0
Schwab Stock Slices, S&P 500 only, ≥ $5/slice, up to 30 at once
~1,130
$0.65FullFullFullLimitedLimitedVariable service fees on certain restrictedmoderate
E*TRADE (Morgan Stanley) logoE*TRADE (Morgan Stanley)Review$0 listed
~20
$0.65FullFullFullFullLimited$6.95 flat on penny stocksmoderate
Fidelity logoFidelityReview$0
Stocks by the Slice, 7,000+ stocks/ETFs, from $1
$0.65FullFullNoNoNo—limited
Merrill Edge logoMerrill EdgeReview$0
$0.65FullFullFullLimitedNo—none
Moomoo logoMoomooReview$0
$0LimitedLimitedLimitedNoNo—limited
Public.com logoPublic.comReview$0
rebate modelLimitedLimitedLimitedNoNo—none
SoFi Active Investing logoSoFi Active InvestingReview$0
$0FullLimitedLimitedNoNo—none
tastytrade logotastytradeReview$0 stocks
$1.00 open, $0 close (capped at $10 per leg)LimitedLimitedLimitedNoNo—limited
Webull logoWebullReview$0
$0LimitedLimitedLimitedNoNo—limited
CenterPoint Securities logoCenterPoint SecuritiesReviewPer-share (day-trader oriented)
per-contractFullFullFullFullFullPer-sharebest
Cobra Trading logoCobra TradingReviewPer-share (day-trader oriented)
per-contractFullFullFullFullFullPer-sharebest
SpeedTrader logoSpeedTraderReviewPer-share (day-trader oriented)
per-contractFullFullFullFullFullPer-sharebest

24-Hour / Overnight trading

These brokers run an overnight session: Charles Schwab (thinkorswim), Interactive Brokers, Robinhood, E*TRADE (Morgan Stanley), Webull, Moomoo, Firstrade. Each publishes its own list of symbols admitted to that session, and those lists are typically limited to large-cap index members. We do not track them per symbol, so check whether QSIis on your broker’s list before planning an overnight order.

Overnight sessions route through ATSs, typically have wider spreads, accept limit orders only, and offer no guaranteed fills.

Penny stock / OTC routing

QSI trades on the OTC markets. Broker support varies sharply by tier (OTCQX, OTCQB, Pink Current, Pink Limited, Grey). Fidelity and Robinhood exclude pink/grey entirely. For short-locate on small-caps, Interactive Brokers and the day-trader specialists (Cobra Trading, SpeedTrader, CenterPoint) have the deepest inventory.

About Quantum-Si Incorporated Class A Common Stock

Quantum-Si Inc is a life sciences company focused on proteomics research and analytical technologies. It develops single-molecule detection platforms designed to enable next-generation protein sequencing (NGPS) and large-scale protein analysis. Its technology supports massively parallel sequencing of proteins and can also be applied to the study of nucleic acids, providing tools for researchers and clinical applications in molecular analysis. The company's revenue is derived from sales of products and services.
Sector
MEASURING & CONTROLLING DEVICES, NEC
Employees
145
Headquarters
BRANFORD, CT
Listed
2021-06-11
Market cap
$163.09M

Frequently asked

Where can I buy Quantum-Si Incorporated Class A Common Stock (QSI)?

QSI is offered by 15 brokers in our matrix, including Firstrade, Interactive Brokers, TradeStation, Charles Schwab (thinkorswim), E*TRADE (Morgan Stanley). Compare commissions, fractional eligibility, and overnight availability in the broker matrix above.

Can I buy QSI after hours or overnight?

Most brokers in the matrix support pre-market (4 AM–9:30 AM ET) and after-hours (4–8 PM ET) sessions. A true overnight session is offered by Charles Schwab (thinkorswim), Interactive Brokers, Robinhood, E*TRADE (Morgan Stanley), and others, but each admits only its own list of symbols — usually large-cap index members — so confirm QSI is eligible with your broker. Overnight sessions route through ATSs with wider spreads and limit orders only.

Does Robinhood offer QSI?

No. Robinhood does not provide access to the OTC tier QSI trades on. Interactive Brokers, TradeStation, and Firstrade have the broadest OTC coverage.

Does Fidelity offer QSI?

Partial. Fidelity's OTC access is tier-limited — see the OTC columns in the matrix to check whether QSI's specific tier is supported.

Does Webull offer QSI?

Partial. Webull's OTC access is tier-limited — see the OTC columns in the matrix to check whether QSI's specific tier is supported.

Is QSI optionable?

Yes. QSI has listed options contracts. Per-contract pricing varies by broker — see the Options column in the matrix.

Is there a tokenized version of QSI?

Not in our current dataset. The tokenized stock universe (Kraken xStocks, Binance Alpha/Ondo, Robinhood EU, Hyperliquid HIP-3) is expanding quickly — we refresh quarterly.

Can I buy a fractional share of QSI?

9 brokers in the matrix offer fractional shares, but each restricts the feature to its own symbol universe — Schwab to the S&P 500, Robinhood to stocks above a market-cap floor, Fidelity to a 7,000-name list. Check the Fractional column above for each broker's scope and minimum, then confirm QSI qualifies.

Related reading

Background on the trading features that apply to QSI.