Treasury Plans to Sell 30 Million G.M. Shares The Treasury Department said on Wednesday that it planned to sell 30 million shares of General Motors in an offering tied to the company's reinsertion into the Standard & Poor's 500-stock index. The sale is part of the agency's previously announced plans to sell its remaining 300 million shares of the automaker, or nearly 18 percent, by early next year. It has said it will sell those shares through predefined written trading plans. The shares came to the government as a result of the $49.5 billion bailout of General Motors in 2009 in the wake of the financial crisis. In December, the Treasury sold 200 million shares back to the company for $5.5 billion, leaving it with 300 million shares. The United Automobile Workers union's Retiree Medical Benefits Trust will also participate in the latest offering, selling 20 million shares. On Monday, Standard & Poor's announced that G.M. would replace H.J. Heinz in the benchmark stock index after the market close on Thursday. Heinz is being taken private by Berkshire Hathaway and the Brazilian-backed investment firm 3G Capital. G.M. had been a member of the original S.&P. 500, established in 1957, until the company's bankruptcy in 2009. The company's inclusion in the index is expected to buoy the stock price, as investment funds that mimic the composition of the S.&P. 500 buy up shares of its newest components. In early trading on Wednesday, shares of G.M. were up slightly, at $35. The stock went public in November 2010 at an offering price of $33. Citigroup, JPMorgan Chase and Morgan Stanley are acting as the joint book-running managers of the proposed offering.