Lesson 1 of 6

Why Delta Matters for Strike Selection

Why Delta Matters for Strike Selection

When you sell a cash-secured put or covered call, the strike price you choose is the single biggest lever you control. A strike too close to the current price collects fat premium but gets breached constantly. A strike too far away is safe but barely worth the capital commitment. Delta gives you a standardized way to compare strikes across any stock and any expiration.

What Is Delta, Really?
For option sellers, delta is a quick proxy for the probability that your short option finishes in-the-money. A put with a -.25 delta has roughly a 25% chance of being ITM at expiration, meaning about a 75% chance you keep the full premium.

Unlike picking a fixed dollar amount below the stock price ("I always sell $5 OTM"), using delta normalizes your strike selection. A $5 OTM put on a $50 stock is 10% away. A $5 OTM put on a $500 stock is only 1% away. Delta accounts for the stock price, implied volatility, and time to expiration all at once.

Fixed Dollar Strikes
  • +"Sell the $5 OTM put" on every stock
  • +Inconsistent risk across different prices
  • +Ignores implied volatility entirely
  • +A $5 move means different things for AAPL vs. F
Delta-Based Strikes
  • "Sell the .25 delta put" on every stock
  • Consistent probability of success
  • Automatically adjusts for IV environment
  • Same risk profile whether the stock is $20 or $200
Approximate OTM Probability
P(OTM at expiry) ≈ 1 - |delta|

The three delta targets that matter most for wheel traders are .20, .25, and .30. Each represents a distinct risk/reward posture. In the next three lessons we will break down exactly when and why you would choose each one.

Pro Tip
When scanning for strikes in your broker platform, sort the option chain by delta rather than scrolling through strike prices. This instantly highlights the strikes that match your probability target.
Key Takeaways
  • Delta is your best proxy for probability of finishing ITM
  • Delta-based strike selection normalizes risk across stocks and IV environments
  • The three key delta targets for premium sellers are .20, .25, and .30
  • Lower absolute delta = farther OTM = higher probability of profit but less premium
Quick Check
1/3

A short put has a delta of -.22. What is the approximate probability it expires OTM (you keep the premium)?