March 27 (Reuters) - Citigroup's ( C ) top executives are weighing buying a U.S. regional bank, Bloomberg News reported on Friday, as the Wall Street giant looks to wrap up a years-long effort to streamline its sprawling operations.

"Senior leaders of the New York-based firm have held preliminary discussions in recent months about trying to acquire a major U.S. regional lender to dramatically ramp up deposits," the report said, citing people familiar with the matter.

"Some executives broached the possibility of a takeover during a meeting with US regulators this year," according to the report.

Shares of the bank were last down 4.5% in afternoon trading.

Citigroup ( C ) did not immediately reply to Reuters' request for comment .