DETROIT — General Motors Corp. reported the largest annual loss for an automotive company today and said it is making a new round of buyback offers to U.S. hourly workers as it struggles to turn around its North American business amid a weak economy.

GM said it lost $38.7 billion in 2007. The loss largely was due to a third-quarter charge related to unused tax credits.

The Detroit-based automaker also today said it was offering a new round of buyouts to all 74,000 of its U.S. hourly workers who are represented by the United Auto Workers.

The 2007 loss topped GM's previous record in 1992, when the company lost $23.4 billion because of a change in health care accounting, according to Standard & Poor's Compustat.

Excluding the tax charge and other special items, GM lost $23 million, or 4 cents per share, for the year, compared with a net income of $2.2 billion in 2006, beating Wall Street's expectations. Analysts polled by Thomson Financial expected GM to post a full-year loss of 95 cents per share.

GM posted a loss of $722 million, or $1.28 per share, in the fourth quarter, compared with a net income of $950 million in the year-ago quarter. Fourth-quarter charges included $622 million to Delphi Corp., GM's former parts division, for its restructuring efforts.

GM reported $181 billion in revenues for the year, down from $206 billion in 2006. Its automotive business saw record automotive revenues of $178 billion in 2007, up $7 billion from a year ago thanks to growth in emerging markets and favorable exchange rates.

But GM's North American division continued to struggle, posting a $1.5 billion loss for the year.

GM's results also were dragged down by its 49 percent stake in GMAC Financial Services, which lost $2.3 billion in 2007. GM reported a $1.1 billion loss attributed to GMAC.

GM barely retained its title as the world's largest automaker in 2007, selling just 3,000 more vehicles than Toyota Motor Corp. GM sold a total of 9,369,524 vehicles worldwide, up 3 percent from the year before.