By Neal E. Boudette Of THE WALL STREET JOURNAL The chief executive of AutoNation Inc. (AN) said on Thursday he expects General Motors Co. (GM) to get a lift in U.S. vehicle sales as a result of the auto maker's acquisition of lending company AmeriCredit. "It will absolutely boost their [new-vehicle] sales," CEO Michael J. Jackson said in an interview. AutoNation is the country's largest chain of auto dealerships and operates 51 stores selling GM vehicles. "It gives me a lot of confidence around GM." The AmeriCredit deal, he added, "is going to make at least a 10% to 15% difference in [GM sales] volume. GM is losing customers even today because of lack of credit among sub-prime customers." (This story and related background material will be available on The Wall Street Journal Web site, WSJ.com.) Earlier on Thursday, AutoNation reported net income up 29% to $47.2 million, while earnings-per-share jumped 38% to 21 cents a share. The Ft. Lauderdale, Fla., company purchased 20.9 million of its own shares during the second quarter, and allocated $250 million for additional share purchases.