5 With the Bank’s prior approval in writing, the Borrower(s) may, during an interest period, prepay a loan (in whole but not in part) by serving the Bank 48 hours' advance notice in writing, subject to payment of any break cost (i.e. the difference between the return the Bank would have received had the loan run to maturity and the return the Bank is able to obtain by the placing of the funds repaid for the remainder of the period in the market).