DETROIT – The Treasury plans to sell its remaining stake in General Motors over the next 15 months, allowing the automaker to shed the stigma of being partly owned by the U.S. government.

GM said Wednesday it will spend $5.5 billion to buy back 200 million shares from the Treasury by the end of this year. The government, in turn, plans to sell its remaining stake of 300 million shares on the open market over the next 12 to 15 months.

GM will pay $27.50 for each share, about an 8 percent premium over Tuesday's closing price of $25.49. The shares shot up about 7 percent to $27.30 in Wednesday morning trading.