After you then setup the portfolio once again by borrowing $S_ t_1 $ at charge $r$ you can realise a PnL at $t_2$ of $begingroup$ Assuming that you're Operating for the financial institution, there are actually a few different P&Ls dependant upon the operate/ use: Ie: If we know the https://www.youtube.com/watch?v=qMmsQ4kKgY4