The fleet-management company strategizes with clients to “analyze your current fleet, identify immediate opportunities for savings and craft a comprehensive plan for the year ahead,” according to its website.

Cavallini said individual customers who trade in multiple vehicles with Enterprise Car Sales also take advantage of the credit.

The company said it only uses trade-in credits in the St. Louis area, something Ray Wagner, the company’s senior vice president of government and public affairs, said happens rarely.

Wagner said only Enterprise Rent-A-Car — not its other brands, Alamo and National — use the credit. The company did not say how much money it saves by using the credit, but Wagner said Enterprise Holdings, which generated more than $24 billion last year in revenue, does not rely on the incentive to turn a profit.

The Department of Revenue said between 6-10% of the 140,000 vehicle trade-in transactions it sees per year involve multiple trade-ins. The agency did not provide a breakdown of business-versus-individual use of the credit.