Detroit ? General Motors Corp.’s board of directors met for a second day Saturday to make the final decision on whether the automaker would complete its restructuring by filing for bankruptcy protection Monday.

The outcome of the meeting could not immediately be determined. GM and the Treasury Department, which has been guiding the Detroit automaker toward a rescue plan that will give taxpayers nearly a three-fourths stake in the company, went into secrecy mode.

GM’s bondholders had a 5 p.m. Saturday deadline to accept an offer to swap their $27 billion in debt for at least a 10 percent stake in a new GM. If the Treasury doesn’t get the amount of support it wants, bondholders could wind up with far less in bankruptcy court.

The Treasury Department had no immediate comment on the deadline passing, and GM spokesman Tom Wilkinson said the automaker did not plan to make any statements Saturday.

GM took a huge restructuring step Friday when the United Auto Workers union agreed to a cost-cutting deal, and early Saturday, Germany’s finance minister said a plan was approved for Canadian auto parts maker Magna International Inc. to move ahead with a rescue of GM’s Opel unit.

But there was still much to do to beat the government’s Monday deadline to qualify for more aid. The company already has received about $20 billion in government loans and could get $30 billion more to make it through what is expected to be a 60- to 90-day reorganization in bankruptcy court.

GM has yet to confirm it will seek bankruptcy protection, but it has scheduled a news conference Monday morning in New York.

The Treasury on Thursday offered bondholders 10 percent of a newly formed GM’s stock, plus warrants to buy 15 percent more to erase the debt. Last week, GM withdrew an offer of 10 percent equity after only 15 percent of the thousands of bondholders signed up.

It was unclear how many bondholders took the latest offer, although a group representing large creditors who hold 20 percent of debt agreed to it. If the 15 percent who took the first offer are added in, that would make 35 percent.

Getting as many bondholders as possible to sign on to the offer in advance of a bankruptcy filing could help the automaker get through the court process more quickly, said Robert Gordon, head of the corporate restructuring and bankruptcy group at Clark Hill PLC in Detroit.