A new General Motors emerged from bankruptcy protection on Friday, far more quickly than most industry watchers had expected, as a leaner automaker aiming to win back American consumers and pay back taxpayers.

A whirlwind 40-day bankruptcy for GM concluded with the closing of a deal that sold key operations and core brands, including Chevrolet and Cadillac, to a new company that will be majority owned by the U.S. Treasury.

The deal was signed between the government and GM executives at the law firm of Weil, Gotshal & Manges, the company's chief bankruptcy counsel, a source familiar with the company said.

Industry analysts viewed the brevity of the bankruptcy as a positive development.

"I think that this type of case would not do well in a long Chapter 11," said attorney Richard Mikels, head of the bankruptcy practice at Mintz, Levin, Cohn, Ferris, Glovsky and Popeo. "The negatives to the business are reduced significantly by getting these companies out of Chapter 11 as rapidly as possible, and therefore the Chapter 11 process has worked in the manner (it) is supposed to because you have quickly a new entity that is free of the overhang of the old GM."