Mini USA on Monday said it sold 1,796 Cooper and Cooper S models in May.
The carmaker said it expects to sell 20,000 units by April.
May sales were split between 1,365 units of the Cooper and 431 of the sportier Cooper S model. Since the vehicles reached dealerships March 22, Mini has sold 4,142 units of both models combined.
Mini, part of BMW of North America, wants to keep the vehicle a niche player in the U.S. market. It is allotting each of its dealerships 300 Minis until April.
There are 59 Mini dealerships in the United States, with 11 more scheduled to open this year. Customers who place an order for a Mini must wait about four months for delivery.
"We are establishing the premium small-car segment," a Mini USA spokesman said. "With lower volume there is an element of exclusivity."