GM Net Income Falls Nearly 49%

General Motors Corp.’s third-quarter net income plummeted nearly 49% from last year, due partly to a 15% drop in sales early in the quarter and the cost of cut-rate buying incentive programs late in the period, the company said today.

The nation’s largest auto maker reported consolidated quarterly net earnings of $264 million, down from $517 million in net income in the year-ago quarter. Earnings per share on GM’s main common stock fell to 56 cents from $1.53 in the third quarter of 1985.