How to Buy Sionna Therapeutics, Inc. Common Stock (SION) Stock
Compare 15 brokers offering SION, check which offer overnight sessions, see options pricing, and confirm OTC tier access.
- Day range
- $3.20 – $3.33
- 52-week range
- $3.19 – $54.97
- Volume
- 874.9K
- Market cap
- $148.30M
Where to buy SION
15 brokers in our matrix offer SION (penny/OTC-friendly subset). Verify availability and current fees with each broker before trading.
| Broker | Commission | Fractional | Extended | Overnight | Options | OTCQX | OTCQB | Pink Cur. | Pink Ltd. | Grey | Surcharge | Short locate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
 FirstradeReview | $0 | ~4,000+ tickers, ≥ $5 | ~1,200 | $0 | Full | Full | Full | Full | Limited | — | limited | |
 Interactive BrokersReview | $0 (Lite) / per-share (Pro) | ~10,000 | per-contract pricing | Full | Full | Full | Full | Full | Per-share pricing applies | best | ||
 TradeStationReview | $0 listed | $0.50 / $0.60 | Full | Full | Full | Full | Limited | $0.005/share OTC (TS Select/TS Go), $0 up to 10,000 shares | strong | |||
 Charles Schwab (thinkorswim)Review | $0 | Schwab Stock Slices, S&P 500 only, ≥ $5/slice, up to 30 at once | ~1,130 | $0.65 | Full | Full | Full | Limited | Limited | Variable service fees on certain restricted | moderate | |
 E*TRADE (Morgan Stanley)Review | $0 listed | ~20 | $0.65 | Full | Full | Full | Full | Limited | $6.95 flat on penny stocks | moderate | ||
 FidelityReview | $0 | Stocks by the Slice, 7,000+ stocks/ETFs, from $1 | $0.65 | Full | Full | No | No | No | — | limited | ||
 Merrill EdgeReview | $0 | $0.65 | Full | Full | Full | Limited | No | — | none | |||
 MoomooReview | $0 | $0 | Limited | Limited | Limited | No | No | — | limited | |||
 Public.comReview | $0 | rebate model | Limited | Limited | Limited | No | No | — | none | |||
 SoFi Active InvestingReview | $0 | $0 | Full | Limited | Limited | No | No | — | none | |||
 tastytradeReview | $0 stocks | $1.00 open, $0 close (capped at $10 per leg) | Limited | Limited | Limited | No | No | — | limited | |||
 WebullReview | $0 | $0 | Limited | Limited | Limited | No | No | — | limited | |||
 CenterPoint SecuritiesReview | Per-share (day-trader oriented) | per-contract | Full | Full | Full | Full | Full | Per-share | best | |||
 Cobra TradingReview | Per-share (day-trader oriented) | per-contract | Full | Full | Full | Full | Full | Per-share | best | |||
 SpeedTraderReview | Per-share (day-trader oriented) | per-contract | Full | Full | Full | Full | Full | Per-share | best |
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 SIONis 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
SION 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 Sionna Therapeutics, Inc. Common Stock
- Sector
- PHARMACEUTICAL PREPARATIONS
- Employees
- 59
- Headquarters
- WALTHAM, MA
- Listed
- 2025-02-07
- Market cap
- $148.30M
Frequently asked
Where can I buy Sionna Therapeutics, Inc. Common Stock (SION)?
SION 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 SION 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 SION is eligible with your broker. Overnight sessions route through ATSs with wider spreads and limit orders only.
Does Robinhood offer SION?
No. Robinhood does not provide access to the OTC tier SION trades on. Interactive Brokers, TradeStation, and Firstrade have the broadest OTC coverage.
Does Fidelity offer SION?
Partial. Fidelity's OTC access is tier-limited — see the OTC columns in the matrix to check whether SION's specific tier is supported.
Does Webull offer SION?
Partial. Webull's OTC access is tier-limited — see the OTC columns in the matrix to check whether SION's specific tier is supported.
Is SION optionable?
Yes. SION has listed options contracts. Per-contract pricing varies by broker — see the Options column in the matrix.
Is there a tokenized version of SION?
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 SION?
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 SION qualifies.
Related reading
Background on the trading features that apply to SION.