Why Delta Matters for Strike Selection

When you sell a CSP or covered call, the strike you pick is the single biggest lever you control. I learned this the hard way -- sell too close to the current price and you collect fat premium but get assigned constantly. Sell too far away and you barely make enough to justify tying up the capital. Delta gives you a consistent way to compare strikes across any stock, any expiration, any market condition.

What Is Delta, Really?

For us option sellers, delta is basically the market telling you the probability your option finishes in-the-money. A put with a -.25 delta? Roughly a 25% chance of being ITM at expiration -- meaning about a 75% chance you pocket the full premium and move on to the next trade.

Here's why I stopped picking strikes by dollar amount. Saying "I always sell $5 OTM" makes no sense -- a $5 OTM put on Ford at $12 is 40% away, but a $5 OTM put on AAPL at $185 is only 2.7% away. Totally different risk. Delta accounts for the stock price, IV, and time to expiration all at once. It's the great equalizer.

Fixed Dollar Strikes

+"I always sell $5 OTM" -- sounds consistent, isn't
+Wildly different risk on a $12 stock vs. a $200 stock
+Completely ignores IV -- are you selling in calm or chaos?
+A $5 move means nothing on AAPL but everything on F

Delta-Based Strikes

–"I sell the .25 delta put" -- works on everything
–~75% win rate no matter the stock price
–Automatically adjusts for high-IV or low-IV environments
–Same risk profile whether you're trading F at $12 or AMZN at $185

Approximate OTM Probability

P(OTM at expiry) ≈ 1 - |delta|

The three deltas I rotate between are .20, .25, and .30. Each one is a different gear. I'll break down exactly when I use each one in the next three lessons -- and the real-dollar difference it makes on stocks like AAPL, AMD, and NVDA.

Pro Tip

Quick hack: in your broker platform, sort the option chain by delta instead of scrolling through 50 strike prices. It instantly highlights the strikes that match your probability target. Saves me a ton of time every week.

The short version

•Delta tells you roughly how likely you are to get assigned -- that's the number that matters
•Delta normalizes risk across any stock at any price in any IV environment
•The three deltas that matter for wheel traders: .20, .25, and .30
•Lower delta = farther OTM = higher win rate but smaller paycheck per trade

Quick Check

1/3

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

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