General Motors Co. is giving about 600,000 employees and retirees in the United States and Canada the chance to buy stock in the company's upcoming initial public offering at the IPO price, reported Automotive News.

GM is offering the directed share program as part of an IPO scheduled for November.

In a letter dated Sept. 30 to employees and retirees, the automaker asked employees and retirees to pre-register their interest in the share purchase program online or via mail by October 15.

The letter says that the company has not determined a maximum or minimum number of shares that an employee or retiree can buy under the program.

The minimum investment is expected to be greater than $1,000, however, according to the letter obtained today by Automotive News.

GM has yet to determine the initial share price of its initial public offering.

Directed share programs are a common way for employees to buy stock in their employers.

GM spokesman Pete Ternes confirmed today that the letter had been sent. But he declined to give details because of regulations governing comments about the upcoming IPO.

Analysts believe the IPO could be one of the largest in recent history, allowing the U.S. government to recoup $8 billion - $10 billion of the more than $49.5 billion it spent to rescue the automaker.

The U.S. government owns about 61 percent of GM, and the Canadian and Ontario governments control 11.7 percent. An independent health care trust controlled by the UAW owns another 17.5 percent of the automaker.

Ternes said GM has received some feedback from employees and retirees that they had not received the letter as of today. He said the company would communicate to employees if an extension is allowed.

The program is being offered to salaried and hourly employees and retirees.

Morgan Stanley Smith Barney is administering the GM share program.

GM has about 54,000 UAW-represented hourly employees and nearly 400,000 UAW retirees.