Subject: Re: Can't belive I did that
But you DON'T HAVE TO deliver old shares held in your account, you can buy new shares and deliver them.

I recently got assigned on a covered call that expired 8/16/24. Options expire at market close, 3PM Central.

At market open on Monday 8/19 there were two entries in my transactions,
sold XXX shares, and Option Assignment.
On the sale, trade date and settlement date were both 8/19/24.
The money appeared in Balances as "settled cash".

I found this comment on a Fidelity board: "Friday options assignments settle on Monday. Reassignment of lots must be made by 9pm (ET) on the settlement date."

Looks to me like you would have to buy the NEW shares in time for them to be settled at market open on Monday, so with T+1 you would need to buy them on Thursday and they'd settle at market close Friday.

Can you buy the NEW shares on Monday and reassign to that lot, which is not settled? Seems unlikely, I think the only way to be sure would be for somebody to try it.