Regulators closed Signature Bank in March after a run on its deposits, marking the fourth-largest bank failure in U.S. history. Now, the Federal Deposit Insurance Corp. is auctioning off thousands of Signature loans backed by apartment buildings and other commercial properties primarily in the New York region. Bids are due Thursday on what is the biggest and most closely watched commercial-property sale of the year. Loans are expected to sell on average 15% to 40% below their original face amount.