Sell to open (STO)
Definition · Level 1 · Options basics
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Order that creates a short option position: you write the contract, collect premium and take on the obligation.
Example
STO 1 Nov 55 call against 100 shares = a covered call.
Where Tradecraft teaches it
Level 1 · Options basics, in the lesson “Reading the chain & opening vs closing”: Bid, ask, volume, open interest, IV, delta — and BTO/STO/BTC/STC.
Related terms
- Buy to close (BTC)Order that buys back an option you previously sold, ending your obligation.
- Buy to open (BTO)Order that creates or adds to a long option position — you become the holder.
- DeltaApproximate change in an option's price per $1 move in the underlying: 0 to 1 for calls, −1 to 0 for puts, about ±0.50 at the money.
- Implied volatility (IV)The volatility input that makes a pricing model reproduce an option's market price, in annualized terms — often read as the move the market is…
- Open interestNumber of option or futures contracts outstanding — not yet closed, exercised or expired — each with one long and one short; reported once a day.
- Option chainTable of every strike for an expiry — usually calls on the left, puts on the right, strikes down the middle — with bid, ask, volume, OI, IV and delta.