Updated with further information on Treasury's reported plan to sell its stake in Citigroup. NEW YORK ( TheStreet ) -- Citigroup ( C ) shares were chugging 5% higher on news that the U.S. Treasury was planning to begin selling its one-third stake in the company in a pre-set trading program. Bloomberg reported earlier Thursday that the plan would lock the Treasury into a pre-set schedule to unload its 27% stake in Citigroup. The Treasury's program would be similar to that of a 10b5-1 program, which is used by many executives and directors of public companies to buy and sell shares of a company at prearranged times without being at risk of insider trading. The plan could be announced as early as next month. The Bloomberg article noted that Treasury would be able to "issue instructions on how many shares to sell, when to sell them and at what price, while eliminating concern that the sales are based on non-public information."