J.P. Morgan Chase & Co. suspended share repurchases just two months after announcing a giant buyback program, in the latest fallout from the trading blunder that has cost the company at least $2 billion in losses, hammered its stock price and tarnished its reputation as the best-managed big U.S. bank.

Chief Executive James Dimon told investors and analysts at a conference Monday that the New York company stopped the buybacks out of an abundance of caution and compliance with a new set of international capital guidelines, saying...