https://money.stackexchange.com/questions/126685/can-a-singl...
If Alice shorts 100 cows on Monday, and then Bob shorts 100 cows on Tuesday, and both are due at close of market on Friday, it’s gonna be a bloodbath.
(Granted, they were some pretty illiquid stocks so I suspect that the broker had managed to get into a naked short situation when they allowed the trade to execute before actually trying to go out and borrow them. Of course, their mistake was made my problem.)
Your short position may have been called, but (I am assuming) you didn't take out a short position with an explicit expiration date. Ie, it wasn't "due" on Friday, and you likely didn't know days/weeks in advance of when it was going to be called.
https://money.stackexchange.com/questions/98418/does-short-s...
So let's imagine there is one share of a stock and person A owns it... they lend it to person B, who sells it to person C, who lends it to person D who sells it to person E....
Now, person E is the only person who currently holds an actual 'share', and is the only person who can lend it out. Person A and C will have an IOU saying they will be given back their share at date x... they can sell the IOU, since it has the same value as a share, but they can't lend out an IOU.
While conceivably what you are suggesting could happen, I don’t know if it ever has.
The share has been lent twice.
There is one share, and Ellen owns it for real.
Everyone else has these agreements involving collateral and promises to get/give a share back.