Mark Cohen of Vanderbilt University, in a study paid for by plaintiffs in a lawsuit against Honda, said 43.3 percent of Honda's African American borrowers were charged a markup, compared with 22.2 percent of white borrowers.
Of those charged a markup, blacks paid an average $557, compared with $227 for whites. The plaintiff's study found the disparities occurred even when borrowers of different races had the same creditworthiness.
His study of 383,652 loans by Honda's own financing arm between June 1999 and April 2003 found black borrowers paid $24.7 million in markups, nearly a quarter of the total, although they were only 12 percent of the company's customers.
The discrimination lawsuit against Honda prompted the contract with Cohen is one of several such class actions filed against major auto financiers in recent years.