LONDON—J.P. Morgan Chase & Co. has been holding discussions with U.K. regulators about the roughly $2 billion of trading losses incurred by the giant bank's investment office, according to people familiar with the matter.

The talks with the Financial Services Authority don't represent a formal inquiry by the regulator, one person said, and it isn't clear whether it will result in any action by the regulatory agency. The FSA has been requesting information from J.P. Morgan about how the trading losses occurred and what steps...