Pension plans for General Motors Corp. employees intend to divest 20 percent of their holdings in satellite TV provider DirecTV Group Inc. by selling 55 million shares, according to a filing with the Securities and Exchange Commission.

No date was set for the sale by the General Motors Special Hourly Employees Pension Trust, the General Motors Special Salaried Employees Pension Trust and the Sub-Trust of the General Motors Welfare Benefit Trust, which together hold 19.7 percent of DirecTV’s common stock. The sale would reduce their stake to 217.9 million shares, or 15.7 percent of the common stock.

The pension funds, advised by U.S. Trust Co., are the second-largest shareholder block in DirecTV after News Corp.’s Fox Entertainment Group Inc., which holds 470.4 million shares, or 34 percent of its stock. The funds’ stake dates to GM’s ownership of a controlling stake in Hughes Electronics. Hughes, formed in 1985, introduced DirecTV in 1994. News Corp. bought GM’s stake in Hughes in 2003, changing its name to DirecTV and selling off its non-satellite TV businesses.

DirecTV shares closed Wednesday at $14.74, up 3 cents on the New York Stock Exchange.