Trading

Sell to Open (STO)

By Ryan Silk & Lawrence Polatchek · Reviewed April 2026 · Options Trading Glossary

Sell an option to open position

What is Sell to Open (STO)?

Sell to Open (STO) Opening a new short option position by selling. You receive premium and take on an obligation if assigned.

Complete Definition

Opening a new short option position by selling. You receive premium and take on an obligation if assigned.

Related Terms

Buy To Open Sell To Close Buy To Close
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Written by
ApexVol Research Team
Quantitative options research
All calculations use live ORATS institutional data — the same source used by professional volatility desks.
RS
Technical reviewer
Ryan Silk, ApexVol Founder
Reviewed for technical accuracy
10+ years trading options. Built ApexVol's pricing engine, Greeks model, and IV-rank methodology.
This guide is updated as market conditions and ORATS data change. Last revised 2026-05-12. How we research →

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