In this economy, there are 10,000 borrowers. Each person borrows $100 for a 1 year loan.

For the lender not to make a loss, the lender must set an interest rate such that they earn at least as much as their outside option of not lending to people from all borrowers that did not default in this economy. In this case, the outside option is the risk-free interest rate on a 1-year US Treasury securtiy. The 1-year USTS pays annual interest rate of i = 0.03. What is the minimum interest rate that the lender will charge to borrow money in this economy