The Canadian Competition Bureau filed an application with the Competition Tribunal seeking to stop Visa Canada Corp. and MasterCard International Inc. from enforcing agreements restraining competition on the fees that merchants pay to accept credit cards. Visa and MasterCard rules allegedly block retailers from encouraging customers to use cash or debit cards, which carry lower acceptance fees, instead of credit cards or from placing a surcharge on purchases made with credit cards. Under the policies, a merchant that wishes to accept payment by Visa or MasterCard must also accept all cards the companies offer, including premium credit cards that carry higher merchant fees. The action seeks to prevent enforcement of each of these rules.