What happens to stock which is the subject of a loan and which is subsequently delivered against a call assignment or put exercise?

Shares which have been closed by IBKR due to SEC Rule 204 relating to "Failed to Deliver" positions will be subject to a standard settlement period, which in the U.S. is 1 business day.

Clients may view our Overview of Short Stock Buy-Ins & Close Outs…

In the event of any of the following, a stock loan created through the Stock Yield Enhancement Program will be automatically terminated in the event of:

• The client elects to terminate program participation
• Transfer of shares…

The loan will be terminated on T+1 of the action date (trade, assignment, exercise) which closed or decreased the position.

Disclaimer…

If you close a securities position which resulted from an option assignment on the date it was assigned to your account, it will be considered a day trade.  Similarly, if you close a securities position which resulted from an option exercise on the date it was exercised to your account, it will be considered a day trade…