Jerry York, a General Motors Corp. director and representative of billionaire investor Kirk Kerkorian, has suddenly resigned from the automaker's board following GM's decision to nix a three-way alliance, according to a regulatory filing reported by Reuters on Friday. GM shares fell nearly 7 percent to $30.82 in midday trading on the New York stock exchange on the news. The resignation was announced by Tracinda Corp., the investment firm headed by Kerkorian, who owns 9.9 percent of GM stock. Tracinda had pushed for the partnership. A GM spokesman was not immediately available to comment. Tracinda also said that it has decided not to acquire additional shares of GM, according to the filing with the U.S. Securities and Exchange Commission. Kerkorian said last week he may consider buying up to 12 million additional shares of the auto giant's common stock. "If you are investing in GM thinking that Tracinda is going to be an agent of change, this is not what you want to see," said Phil Orlando, chief portfolio manager of Federated Investors in New York, which does not hold GM shares. "With GM having rallied almost 90 percent in the last year, this is not what investors want to be seeing." GM said on Wednesday it was breaking off talks with Renault SA and Nissan Motor Co. on a three-way alliance that was urged by Kerkorian, GM's largest individual investor. Tracinda said earlier this week that it believed a tie-up between GM and Renault -Nissan would have produced "substantial synergies and cost savings" for GM and regretted "that the board did not obtain its own independent evaluation" about the possible tie-up.