Shares of Citigroup pared earlier gains as the stock resumed trading before the opening bell.

Citigroup said in a regulatory filing it was proposing an exchange offer of preferred shares that would substantially increase the U.S. government's ownership in the bank.

As part of the plan, Citigroup would conduct a reverse stock split, reducing its share count and boosting its share price.

(Reporting by Ellis Mnyandu; Editing by Kenneth Barry)