CHARLOTTE, N.C. — A Kansas company that is part of Warren Buffett’s Berkshire Hathaway Inc. has stopped selling private bank deposit insurance above the amount guaranteed by the federal government, signaling that billionaire investor Buffett may be worried about future bank failures.

Kansas Bankers Surety Co. confirmed Wednesday that it has ceased soliciting new clients for their “bank deposit guaranty bonds,” a product that backs deposits above the $100,000 limit that is guaranteed by the Federal Deposit Insurance Corp. for many bank accounts. It also plans to cancel existing policies in coming months.