◈ GLOSSARY · TRADING & MARKETS
Delta (Options Greek).
A definition, in plain English — with the books that teach it.
Reviewed by ClearValue Editorial Team · Jun 27, 2026
◈ DEFINITION
What it means
Definition
How much an option's price is expected to change for a $1 move in the underlying stock. Call deltas run from 0 to 1; put deltas from 0 to -1. Delta is also a rough proxy for the market's implied probability the option finishes in-the-money — a 0.30-delta call is loosely a 30% shot.
◈ IN PRACTICE
Example
You own a call with a delta of 0.50, currently priced at $3.00. The stock rises $1. The call's price moves to roughly $3.50 — a 50-cent gain per share, or $50 per contract.