Deposits at U.S. banks exceed loans by an unprecedented $2 trillion as the threat of a slowing economy tempers borrower demand and lenders preserve tightened standards.

Cash deposited at firms from JPMorgan Chase & Co. to Bank of America Corp. expanded 8.7 percent this year to a record $9.17 trillion through Dec. 5, Federal Reserve data show. That outpaced a 3.7 percent gain in loan assets to $7.17 trillion. The gap between what banks take in and lend out has surged since October 2008, the month after Lehman Brothers Holdings Inc. collapsed, when loans exceeded deposits by $205 billion.