(This January 7 story corrects headline to clarify four senior executives are leaving the company, not its four top executives.)

(Reuters) - AutoNation Inc said on Monday four senior executives including chief operating officer are leaving the company as it restructures to cut costs and expects automotive retail to be challenging this year.

The top U.S. auto retailer is consolidating its regional structure from three regions to two and expects the restructuring to save about $50 million annually, it said.

AutoNation said COO Lance Iserman and Chief Technology Officer Tom Conophy will leave effective immediately, while its chief human resource officer, Dennis Berger, will leave at the end of the month.

Fort Lauderdale, Florida-based AutoNation appointed company veteran James Bender as executive vice president of sales.

It also said Donna Parlapiano, executive vice president, franchise network, merger & acquisitions, and corporate real estate, elected to retire on Jan. 3.

The restructuring comes as analysts forecast a dip in U.S. vehicle sales this year. New vehicle sales in the United States are expected to drop as higher interest rates and rising prices could prompt customers to hold off their car-buying plans, the National Automobile Dealers Association said last month.

Recently, the company introduced a used-car subscription service from auto-leasing startup Fair through its network of more than 300 U.S. dealers.

In October, CEO Mike Jackson told Reuters the company planned to reduce investment following an “elevated period of brand extension investment” in higher-margin service and used car operations to offset the squeeze on profits from new vehicle sales.

AutoNation did not immediately respond to a query about any potential job cuts due to the restructuring.