UPDATE 1-GM sale of Saab looms as speedy Koenigsegg steps up

*Tiny supercar maker Koenigsegg close to Saab deal-source

*GM CEO declines comment on progress toward Saab sale (Adds comment from GM CEO)

STOCKHOLM, June 12 (Reuters) - General Motors GMGMQ.PK is close to selling its loss-making Saab unit after tiny Koenigsegg agreed to ride to the rescue of its fellow Swedish carmaker, a source familiar with the talks told Reuters.

A deal would put a company that has less than 50 employees and turns out only a handful of $1 million supercars in charge of Saab, which produces that many family cars every hour.

Sweden would also likely join other governments backing swift rescues of their biggest car companies with state guarantees to help save jobs and one of the country's biggest brand names.

Koenigsegg, whose slinky supercars can top 400 km/h (240 mph) and rank in Forbes magazine's list of the world's 10 most beautiful cars, is backed by Norwegian investors, a source told Reuters on Thursday.[ID:nLB799437]

The two sides have signed a letter of intent and financing has been agreed, leaving only minor issues to be resolved, the source said.

Saab said on its website on Friday that new ownership would be finalised in the early summer and Swedish television reported that a preliminary deal was now with the U.S. Treasury Department with further information expected to be released next week.

In Washington, GM Chief Executive Fritz Henderson declined to comment on progress in the effort to find a buyer for Saab.