(Updates with details on Black Oak, statement from GM)

By Kate Linebaugh and Sharon Terlep

With time running out for General Motors Corp.'s (GM) troubled Saturn brand, a group that includes private-equity firm Black Oak Partners LLC came forward Wednesday as potential buyers.

The group would initially sell GM vehicles through Saturn's network of 440 U.S. and Canadian dealers and later aim to add vehicles from other auto makers and would seek to transform Saturn into a fuel-efficient brand.

A GM spokesman said Wednesday the Oklahoma City-based Black Oak group is among several bidders interested in Saturn, and that the auto maker plans to update dealers within the next week on the future of the brand.

GM in February promised it would have more clarity on Saturn by April 17.

The auto maker is struggling to offload Saturn, along with its Hummer and Saab brands, as it faces a June 1 deadline to restructure the business or face a government-ordered bankruptcy. A $13.4 billion government loan is keeping GM afloat as the company scrambles to slash billions in debt and overhaul its global operations after President Barack Obama shot down the company's first survival plan.

John Pappanastos, a spokesperson for the investor group , said they have had contact with officials from the Treasury Department after they made their offer to GM on April 8. The group also has received gauged interest from other manufacturers seeking a distribution network, such electric vehicle companies, Pappanastos said.

The precarious financial state of GM's ailing brands and a global credit crunch have complicated GM's efforts to find buyers for its brands.

GM spokesman Steve Janisse said the company is weighing several options for Saturn, including spinning the unit off to its dealers.

GM, in a statement, said it "is simply premature at this time to speculate on what any eventual outcome may be," for Saturn. "When we have additional information on this topic, we will communicate to all involved."

Saturn, created by GM in 1985 to fend off competition from Japanese-based rivals such as Toyota Motor Co. (TM), has underperformed GM's already dismal company-wide sales. In December, GM announced a plan to kill or sell Saturn by 2011.

In February, The Wall Street Journal reported some Saturn dealers want to spin off the brand and sell it separately. At the time, then-Chief Executive Rick Wagoner said the company could be very open to such an offer. Wagoner was ousted in late March by the U.S. government.

The Black Oak group said its proposal for the brand would preserve 10,000 U.S. jobs and keep the Saturn retail network alive.

The parties didn't provide financial details of the proposal, but the investor group's Pappanastos said the investor group expects that it will take capital investment to transform the brand.

The investment group bidding on Saturn includes several investors in addition to Black Oak, an Oklahoma-based private equity fund that owns auto consultancy EFG Companies, which was founded by Oklahoma car dealer Bob Moore. Bob Moore Auto Group in Oklahoma City currently has a Saturn franchise.

Black Oak is involved in auto distribution and services, oil and gas and real estate businesses, among other ventures.

A spokesperson for the group wouldn't say where the financial backing from the deal would come from or who else is involved but said the information will be forthcoming in the next five to 10 days.

The group says its proposal would relieve GM of franchise agreement liabilities and fallout on other brands if it closed Saturn dealerships, and would give the Saturn retailers the opportunity to make returns on their existing operations

-By Kate Linebaugh and Sharon Terlep, Dow Jones Newswires; 248-204-5515; kate.linebaugh@dowjones.com