Lending Club has until June 21 to respond. It has said it will cooperate fully with the investigation. Hailed as a "fintech" rival to traditional banks in the wake of the financial crisis, lenders like Lending Club enjoyed rapid growth and attracted plenty of investor dollars through their promise to provide quick and cheap unsecured personal and business loans online. Unlike banks, which retain some of the risk from the loans they make, marketplace lenders sell the loans on to hedge funds, pension funds or individual investors. U.S. regulators have taken baby steps so far to regulate the sector with the Treasury this month calling for greater scrutiny. The NYDFS can determine whether a lender's interest rate practices comply with the state's usury laws, which cap interest rates at 16 percent. Lending Club charges interest rates as low as 5 percent and as high as 29 percent, according to the company's data.