Black Americans are required to pay higher interest on loans than their Caucasian counterparts when they finance their cars through American Honda Finance Corp., the U.S. loan unit of Honda Motor Co., according to the Consumer Federation of America.

The federation said a fresh study by Mark Cohen, an expert witness for plaintiffs in class-action lawsuits against automakers, shows that 43.3 percent of black American borrowers are charged higher interest, compared with 22.2 percent for Caucasian borrowers.

Black borrowers on average pay more than twice the amount in subjective interest -- $557 -- compared with $227 for Caucasian borrowers, the study shows.

"AHFC's credit pricing policy has a differential markup cap based on credit tier. While most customers are limited to either a zero or 2 percent markup, the least creditworthy tier allows for a 3.5 percent markup for buyers of new cars," wrote Cohen, a professor at Vanderbilt University.