General Motors Corp. (GM) is offering dealers $100,000 to $1 million to go out of business voluntarily before the auto maker moves to force them out of business in bankruptcy court, a dealer familiar with the situation said.

A day after its bankruptcy filing, GM on Tuesday sent letters to each of its 6,000 dealerships informing them whether they are marked to close or not under the auto maker's plans to shed thousands of U.S. dealerships.

In the letter, GM tells dealers on the closing list they can no longer buy new vehicles but have until October next year to sell down their inventory, according to a dealer who received one of the letters.

The auto maker has said it plans to shutter 2,400 dealerships. The company sent letters to 1,000 dealers last month informing them they are on the closing list.

Dealers have until June 12 to accept or decline the offer. If they decline, the dealers will have to take their chances fighting GM in bankruptcy court. Chrysler LLC dealers in the same position have had little luck challenging the auto maker in Chapter 11 proceedings. Chrysler is taking advantage of bankruptcy to close 789 of its 3,200 dealers.

"This is a very fair settlement we believe we're offering to the dealers," GM Chief Financial Officer Ray Yong said Tuesday in a conference call with analysts and media.

Young said GM has set aside a pool of money to buy out dealers, but wouldn't say how much the auto maker expects to spend. He also said the company expects litigation from dealers will add to the unsecured claims GM must deal with in court.

The dealers that remain, Young said, will be expected to operate at a 'very, very' high performance level.

-By Sharon Terlep, Dow Jones Newswires; sharon.terlep@dowjones.com