Picking a strike: what each delta actually buys
Delta is the fastest read on a covered call strike. A 0.30 delta call has roughly a 30 percent chance of finishing in the money, so roughly a 70 percent chance you keep the shares. Higher delta means more premium and more assignment. That is the only trade-off, and everything else is detail.
Most strike advice is a table of deltas with no opinion attached. The table is useful, so here it is, but the opinion is the part worth having.
The map
| Delta | Keep the shares | Premium | Reads as |
|---|---|---|---|
| 0.10 | about 90% | Thin | I want the shares, the premium is a tip |
| 0.20 | about 80% | Modest | The common default for a reason |
| 0.30 | about 70% | Decent | Income is the point, I accept getting called |
| 0.50 | about 50% | Fat | A coin flip on whether I still own this |
Those percentages are the model's estimate, not a promise, and delta systematically overstates the true probability of finishing in the money for out-of-the-money strikes. Close enough to steer by. Not close enough to bet the account on.
The opinion
0.20 to 0.30 is where this strategy actually works, and the reason is not the premium. It is that at 0.20 delta you get called away about one time in five, which is infrequent enough that you keep compounding the shares and frequent enough that you are being paid a real amount for the risk.
Below 0.10, you are collecting $0.15 on a $70 stock and paying two commissions and a spread to do it. The yield is a rounding error and the assignment risk, while small, is not zero. It is busywork that feels productive.
At 0.50 you are effectively agreeing to sell your position on a coin flip every month. That is not an income strategy, it is a slow-motion exit. If you want out, sell the stock.
Delta is not the first filter
Here is where most strike guides mislead. You pick the delta band first and then find that the 0.22 delta strike has 14 contracts of open interest and a market of $0.40 by $0.75. Now what.
The honest ordering is: liquidity, then the calendar, then delta.
- Liquidity. If the spread is 30 percent of the premium, your real credit is not the mid. On a $0.62 mid with a $0.40 by $0.85 market, assuming you fill at $0.62 is optimistic and assuming $0.50 is realistic.
- The calendar. Earnings inside the expiry window changes the distribution completely and no delta captures it. So does an ex-dividend date, which changes your early assignment risk.
- Delta. Now pick within what survived.
A 0.20 delta strike on a chain you cannot get filled on is worse than a 0.30 delta strike on one you can.
The strike test that beats all of this
Would you be content selling at that price. Not indifferent, not resigned. Content.
If the answer is no, you have picked the wrong strike, and no delta number fixes that. This is the same test from the end-to-end walkthrough and it keeps showing up because it keeps being the thing that decides whether people stay in this strategy or blow up on one stock that ran.
OptionsKing scores every candidate strike on a deterministic 0 to 100 scale and shows you nothing below 60, at any setting, with 75 the recommended bar. How it works covers what that guarantees.
Questions people actually ask
Is 0.30 delta too aggressive for covered calls?
No, if you are genuinely willing to sell at that strike. You will get called away roughly 30 percent of the time, which on a monthly cadence is several times a year. Aggressive is writing 0.30 delta on a stock you have no intention of parting with.
Should I pick the strike or the delta first?
Neither. Check liquidity and the calendar first, then choose a delta among the strikes that survived, then look at what dollar strike that lands on and apply the would-I-be-content test.
Why does delta overstate the odds?
Delta approximates the risk-neutral probability of finishing in the money, which is not the real-world probability, and the two diverge because of volatility skew and the drift the model assumes. It is a good navigational tool and a poor guarantee.
Keep reading
Do the math on your own trade
Every price in this article is an illustrative worked example, not a quote. Read Covered calls for the rest of the series, and the disclaimer before you act on any of it. Selling options carries real risk of loss, and the loss can be far larger than the premium you collected.