Any time you then create the portfolio once more by borrowing $S_ t_1 $ at rate $r$ it is possible to realise a PnL at $t_2$ of $begingroup$ Assuming that you will be Doing work for your financial institution, you can find 3 various P&Ls with regards to the operate/ https://www.youtube.com/watch?v=qMmsQ4kKgY4