MasterCard Inc. today said it would begin posting U.S. interchange rates, effective Nov. 1

Bowing to merchant demands for cost transparency, . Interchange is one component of the discount rate that acquiring banks charge merchants to accept credit cards. The discount rate is one source of revenue for corporations that negotiate rebates as part of their corporate card agreements. A Federal Reserve Study in May 2005 said the average interchange fee is about 1.56 percent, varying by merchant and purchase type. MasterCard and Visa face dozens of lawsuits on interchange rates. Visa this month began offering merchants access to operating regulations, provided customers sign a non-disclosure agreement.