Delta measures how much an option's price moves per $1 in the underlying stock. But for put sellers, it doubles as something more useful: a rough probability read.
Delta as a Probability Dial
A put with a delta around 0.30 suggests roughly a 30% chance of finishing in-the-money — which means about a 70% probability of expiring worthless. No single trade is ever guaranteed, but over many trades, that probability tends to hold.
The Trade-Off
- Lower delta (further OTM) → safer, more cushion, less premium.
- Higher delta (closer to stock) → more premium, assignment closer.
We use delta to balance the income we want against the cushion we need. A 0.30 delta isn't a rule — it's a starting point that we adjust based on IV Rank, support, and how much we want to own the stock at the strike.
Delta Plus Support
Delta alone is mechanical. The real edge comes when you pair it with a technical level — selling a 0.30 delta put that also sits below confirmed support means the stock has to break real demand before it reaches your strike. That's probability layered on probability.