* Treasury selling at least 358 mln shares in IPO
* No timeframe for reducing investment further- official (Adds Treasury comment, lockup period, fees)
WASHINGTON, Nov 17 (Reuters) - The U.S. Treasury will raise
gross proceeds of at least $11.8 billion in the General Motors
Co
Senior administration officials told reporters late on Wednesday that Treasury could unload up to 412 million shares if an overallotment option is exercised, increasing the government's gain to $13.6 billion and reducing its stake to 33 percent.
The gross sale proceeds do not include nominal fees the government will pay to the IPO underwriters.
The Treasury extended GM $50 billion in 2009 and took a 61 percent stake after the company emerged from a government-led bankruptcy.
"We achieved our objective," one official said about the the size of the minority government stake in GM that will remain.
The Treasury has agreed to not sell additional shares for six months. Terms of Treasury's oversight of GM will remain in force, but the agency will scale back its involvement.
There is no timeframe for fully exiting GM, Treasury said.
GM pulled off the biggest IPO in U.S. history, raising $20.1 billion after pricing shares at the top of the proposed range in response to huge investor demand.
Shares begin trading on Thursday on the New York and Toronto stock exchanges. (Reporting by John Crawley and David Lawder; Editing by Leslie Adler)