Assignment, Margin & Tax Traps

American-style options (SPY, QQQ) can be assigned any time. Short ITM calls are most at risk right before the ex-dividend date.

If your short call is ITM and its remaining extrinsic value is less than the dividend, expect assignment.

Pin risk at expiration: if the stock closes right at your short strike, you don't know if you'll be assigned until Monday. Close or roll before the bell.