General Motors Corp faces a government-imposed June 1 deadline to reach sweeping cost-cutting deals with bondholders and its union and has said it is probable it will follow rival Chrysler into bankruptcy.

GM, which has been slashing jobs, plans to cut its U.S. brands to four from eight and said on Friday that it expected to have about 3,600 U.S. dealerships by the end of 2010, down from just under 6,000 as of mid May.

Key upcoming dates for GM are as follows.

* May 20 - Italy's Fiat SpA is to present its plan for GM's Opel European operations under a deadline set by Germany. Fiat is in the process of acquiring up to a 35 percent stake in bankrupt U.S. automaker Chrysler.

* May 27 - Deadline for holders of some $27 billion of GM unsecured debt to decide whether they will exchange their debt. GM has said that it must get a 90 percent participation or it would have to seek bankruptcy protection.

* May 28 - GM plans to make monthly payment to North American parts suppliers, moving them forward from June 2.

* May 31 - Some 1,100 U.S. dealers notified by GM on May 15 that their long-term franchise agreements ending in October 2010 would not be renewed have until the end of the month to submit new information to the automaker. GM does not believe that new information would change its position.

* June 1 - $1 billion bond payment due, but GM has said it did not expect to make the payment because it would either be restructuring the debt voluntarily or through a bankruptcy court process.

* June 2 - Automakers scheduled to report May auto sales. Investors could put a special focus on Chrysler, which filed for bankruptcy protection April 30, and GM with expectations now leaning toward a bankruptcy filing.

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