What's with this time limit on shorting a stock? There are various reasons one might need to cover a short sale, but a time limit isn't one of them... I happen to have an account at Schwab and this is their fairly well written take on it. Some stuff in there I didn't know as in you could be forced to cover the short at any time if there are no longer any shares to borrow and that if you have a margin account and allow your stock to be borrowed, dividend 'payments' might have alternate tax treatment (here in the USA anyway).
https://www.schwab.com/active-trader/insights/content/9-frequently-asked-questions-about-short-selling
When you start talking about time limits, I'm thinking stock options which adds yet another level of confusion.
If you are interpreting my post and/or nctnico's post as having a time limit, are you inferring something that is slightly different.
With shorting, you "borrow a stock to sell". Borrowing means you will eventually have to pay it back. So, there is a time duration you are operating under. Since lender is gambling that the
stock will go up within the duration, and borrower is gambling that stock price will
go down in the duration, the exact duration is important. It is a time limit only in the sense you are reaching the date you must pay back the stock.
I am skipping lending/transaction fees and such. With a large enough fee, the lender can still make money can still be made even if the stock goes down.