Lesson · [ 15 ]

DELTA DEEP DIVE

Intermediate6 min

Plain English

Delta serves double duty. It tells you (1) how much your option moves per $1 stock move, and (2) roughly, the probability that the option expires ITM. A 0.30 Delta call has about a 30% chance of being ITM at expiration.

Going deeper

Delta ranges from 0 to 1 for calls and 0 to -1 for puts. ATM options have a delta near 0.50 (calls) or -0.50 (puts). Deep ITM options approach 1.0 or -1.0 (acting like stock). Far OTM options approach 0 (barely moving with the stock). Delta is also used as a rough probability proxy — a 0.20 delta call has approximately a 20% chance of expiring ITM. Position delta (net delta across all legs) tells you the overall directional bias of a multi-leg strategy. Delta-neutral strategies have a net delta near zero.

Examples

Delta as Probability

You sell a 0.16 delta put. This means there's roughly an 84% probability that the put expires worthless (out of the money), and you keep the premium.

Portfolio Delta

You own 100 shares of SPY (delta = 100) and sell a 0.30 delta call (delta = -30). Your net delta is 70. You still have bullish exposure but less than owning stock alone.