A couple thoughts after the initial release.

Front page an identifier under PO Client Box (or elswhere) stating there are open loan requests with a link to the Loan Shark.
PM to borrower indicating a loan offer available
PM to lender upon consumation
PM to lender upon payback

On the Loan in Progress a couple more fields visible including

Days until loan due
On last day in bold red letters Loan Due Today
Mid-day on loan due date a PM sent to buyer as reminder of loan due

I believe the additional communications will help to facilitate and keep less loans from defaulting....they could go into auto default just from forgetting. Furthermore there could be a check box when the loan is originally set up that says Auto-Repay and the server checks for available funds to repay loan before letting it go into default. Additionally in the event it has not been considered, when debit balances exist the PO Client balance should be checked and garnished if available.