Just wondering if anyone has had a problem like this - options you are short getting exercised early? What were the consequences? A related situation is - options in the money, not marketable or not saleable near expiration (this has happened to me once).
The only issues I can think of is the possibility of higher margin on the short stock vs. the short call, the stock can be hard to borrow and you might owe a dividend with the short stock, but not the short call.
If there's TP remaining, early exercise can be a good thing. I once had short MSO calls with over a pt. of TP assigned. Covered and re-sold them at the open. No complaint there Another consequence of short stk assignment of a hard to borrow stock can be high carry cost (see 100+ % ind. rates on fin'ls 3 yrs ago).
You'd have to call your broker to determine their policy but I wouldn't be surpised if they covered the assigned position ASAP in the after market at the WORST possible price. And if that didn't CYA then they'd start liquidating other positions, if anything, that you have in your account. And for sh*ts and grins, a restricted account to boot. But that's all just a guess. If you don't have the wherewithal to swallow an assignment, either trade the appropriate position size for your account's size or hedge the original position to achieve the same.