Jeff Dyke, Sonic's executive vice president of operations, welcomed AutoNation to the used-car market. "It's fantastic," said Dyke. "They're late to the party, but I couldn't be more supportive."
Consumers will benefit from added competition, said Dyke, who is not concerned EchoPark will lose market share.
"EchoPark is years ahead of anything that AutoNation and Asbury have to offer," he said. "The way you'll be successful in the used-car business is by having the ability to manage inventory. I think we do that better than anyone in the business."
Sonic aims eventually to have 10 EchoPark stores in each of more than 50 U.S. markets. It already is moving beyond the initial stores in Denver to markets elsewhere in Colorado plus Texas and the Carolinas. Next: Georgia and Florida.
"About two months ago, we bought Auto-Match, which has four used-only stores in Georgia and Florida," said Dyke. "We'll convert those to EchoPark stores by end of 2017."
Attempts to reach CarMax and Asbury for comment were unsuccessful.
AutoNation has tried to build used-vehicle sales in various ways since closing a chain of used-car superstores more than 15 years ago.
At one point, it had more than a dozen Value Vehicle Outlets and Premium Vehicle Outlets at franchised dealerships and focused on older, higher-mileage cars. Some of those have closed, and Jackson said the rest will go away with the advent of AutoNation USA stores.
"It's a marketplace ripe for disruption," Jackson said, "where the consumer is aching for a more transparent, trusting experience than what's fully available today."
Jamie LaReau contributed to this report.