When a long option expires in-the-money, it auto-exercises into stock. A long call becomes a purchase of 100 shares at the strike — on SPY, roughly $74,000. If your account can't cover that, the broker doesn't just eat it. It steps in.

The typical sequence

Exercise happens over the weekend/overnight after expiration, so you often don't see it until the next session. Then your broker, finding an account that's suddenly holding stock it can't pay for, will liquidate the position — usually at the market open. You keep the difference between the strike and where it sells, minus fees, but you're exposed to overnight gap risk: if SPY gaps down before the broker closes the shares, your in-the-money win can shrink or flip to a loss.

The moment you let an ITM option settle, you've swapped a clean cash exit for a stock position and an overnight gap you can't control.

Margin, calls, and fees

If the exercise pushes you past your buying power, expect a margin call and possibly forced liquidation of other holdings to cover it. There can be assignment/exercise fees on top. None of this is punishment — it's just the plumbing doing what it does when an option settles into a position you can't fund.

The one-line fix

Close in-the-money options before expiration. A same-day scalper should be flat by the close, full stop — it turns this entire scenario into a non-event.