The giant U.S. bank Citigroup says it is distributing stock options to its employees in a bid keep them on board at the bailed-out institution.

An estimated one-quarter of its workers, about 75,000 employees, would be covered by the stock option program, which could result in sizable gains for the workers should Citigroup's stock price rebound from its current $4 per share, The New York Times reported.

Many Citigroup bankers had seen their nest eggs vanish when the company's stock price fell from $56 per share and U.S. taxpayers contributed $45 billion to save the faltering firm, which had been heavily exposed to subprime mortgages. The Times said the bank could issue 2 million to 3 million stock options, worth an estimated $11 million at today's prices.

"We have implemented a broad-based options program that links employee rewards to the long-term performance and success of the company," said bank spokesman Stephen Cohen.

"With stock options, you can make a lot of money if the stock price goes up, but you are not losing anything if it falls," compensation analyst Paul Hodgson of the Corporate Library told the Times