Domestic car sales fell 14.9 percent in early July compared with a year ago and analysts saw further evidence of a weakening new-car market, according to company reports released yesterday.

Analysts pointed out that the July 1-10 period a year ago was so strong that a decline for the period this year was inevitable. But the decline in early July was the third in as many reporting periods.

Nevertheless, Chrysler Corp. announced a $400 rebate program yesterday on its Dodge Aries-Plymouth Reliant compact cars, and the trade journal Automotive News said dealer inventories were at a four-month high.

General Motors Corp. suffered an 18.6 percent decline in sales for the period compared with last year. Ford Motor Co. sales were down 9.6 percent and Chrysler sales were down 5.3 percent.

GM's market share dipped to 55.4 percent, more than 4 percentage points below its traditional share, while Ford and Chrysler posted gains in market share to 26.3 percent and 13.6 percent respectively.

Among the small producers, sales were down 4.5 percent at American Honda Motor Co. Inc., off 50.4 percent at American Motors Corp. and down 11.4 percent at Volkswagen of America Inc.