Taxpayers will take in $1.03 billion in proceeds from Thursday's planned Treasury Department sale of General Motors stock.

The sale of 30 million shares was planned to coincide with GM's return to the S&P 500 on Thursday. Treasury said that it would sell the stock at $34.41 per share. A trust fund controlled by the United Auto Workers union also sold 20 million shares for about $688 million, Treasury said.

Standard & Poor's announced this week that GM would return to its benchmark index at the close of trading Thursday, replacing H. J. Heinz Co. GM, one of the original members of the S&P, fell out of the index in 2009 when it went through bankruptcy and a federal bailout, which left Treasury with a majority stake in the company.

GM's return to the S&P lifted the stock to a 52-week high Tuesday, as managers of S&P index funds rushed to buy shares to keep their portfolios in line with the index. Shares of GM (GM) fell Wednesday following the Treasury's announcement of the planned stock sale, but rose slightly Thursday during both regular and after-hours trading.

Related: Chrysler refuses to recall 2.7 million Jeep SUVs

GM shares are up more than 23% over the last three months, boosted by a rebound in demand for cars by U.S. consumers.

During 2010's initial public offering, Treasury and the UAW trust fund, set up to pay the cost of health care coverage for hourly retirees of the company, started selling the shares of the automaker they received as part of the reorganization.

In December, Treasury announced that GM was buying back 200 million shares of its stock, and that it planned to sell its remaining 300 million shares over the subsequent 12 to 15 months. After Thursday's sale, the Treasury will still own about 189.2 million share of GM stock, Treasury said.

Related: TARP bailout close to breaking even

Heinz (HNZ) is leaving the S&P because it is in the process of being purchased by Warren Buffett's Berkshire Hathaway (BRKA) and 3G Capital.