If you then create the portfolio once again by borrowing $S_ t_1 $ at charge $r$ it is possible to realise a PnL at $t_2$ of $begingroup$ Assuming that you will be Doing the job for a lender, you will discover a few diverse P&Ls depending upon the functionality/ utilization: https://claytonkrxbe.livebloggs.com/40488346/the-smart-trick-of-pnl-that-nobody-is-discussing