DETROIT (Reuters) - General Motors Co GM.N on Monday outlined in a regulatory filing contacts with billionaire hedge fund manager David Einhorn who went public last week with a plan to boost GM's value and announced its slate of board nominees, all of whom currently serve on the board.

FILE PHOTO -- Mary Barra, chairwoman and CEO of General Motors, discusses the future of the auto industry and the state of the U.S. economy in Washington, DC, U.S. February 28, 2017. REUTERS/Yuri Gripas/File Photo

Einhorn, who runs hedge fund Greenlight Capital, has proposed that GM create two classes of stock, one that pays a dividend and one that does not, to boost the No. 1 U.S. carmaker’s share price.

GM has rejected the proposal and rating agencies have said it would negatively affect the company’s credit rating. Other investors in the carmaker have also given the proposal from Einhorn, who runs Greenlight Capital, a frosty reception.

Einhorn has said he would take his plan to GM shareholders through a proxy contest where he hopes to win board seats, though he has not released any names.

According to GM’s proxy filing, Einhorn first reached out to the company last August, and followed with a number of in-person meetings, teleconferences and calls, including with GM chief executive Mary Barra.

GM said it also analyzed Einhorn’s proposal including discussions with rating agencies.

In December GM’s board reviewed analyses of Einhorn’s proposal conducted by management and financial advisers and “determined that it was not in the best interests” of GM or shareholders.

Greenlight, which has a 4.9 percent stake in GM including options, declined to comment.

In the filing GM also said that Barra’s salary, bonus and awards declined more than 20 percent in 2016 to $22.6 million from $28.6 million in 2015.

The company said this reflected a one-time retention bonus of nearly $11.2 million in stock options in 2015.

GM reported a pretax profit of $12.5 billion in 2016, up from $10.8 billion in 2015.

Last week No. 2 U.S. automaker Ford Motor Co F.N said its chief executive Mark Fields' salary, bonus and stock awards rose 8 percent to $18.8 million in 2016, while pretax profit for the automaker fell slightly from a record high in 2015.

In late February Fiat Chrysler Automobiles NV FCAU.NFCHA.MI said chief executive Sergio Marchionne received $11.6 million (10.83 million euros) in pay and benefits for 2016.