Barclays Plc (BARC) is being investigated by regulators seeking to determine if it broke information- sharing rules when setting the London interbank offered rate,

Barclays Plc (BARC) is being investigated by regulators seeking to determine if it broke information- sharing rules when setting the London interbank offered rate, a person briefed on the probe said.

U.S. and U.K. regulators are examining if communications between Barclays’s traders and its treasury broke regulations that stop information being shared across the bank, said the person, who declined to be identified because the details of the investigation are private. The Financial Times reported the inquiry on its website yesterday.

Barclays, the U.K.’s third-biggest bank, is among banks including Citigroup Inc. (C) and UBS AG that have received subpoenas from U.S. regulators investigating whether some firms manipulated the Libor rate, two separate people familiar with the probe said yesterday. The U.S. Department of Justice, Securities and Exchange Commission and Commodity Futures Trading Commission are working together with the U.K.’s Financial Services Authority on the probe.

Spokesmen for London-based Barclays, the BBA and Financial Services Authority declined to comment when contacted by Bloomberg News. A Citigroup spokesman declined to comment.