American Express Co. filed a complaint Tuesday against Visa International, asserting anticompetitive activities in Europe by the bank card association.
The filing attacked a Visa bylaw proposal that would prohibit the association's member banks abroad from issuing a competitor's card brand.
American Express complained to the European Commission in Brussels, the governing body of the European Union, which also oversees competitive issues.
The complaint stated that the Visa bylaw would violate the Treaty of Rome, a principal source of competition law within the European Union.
If the bylaw takes effect, it would scuttle American Express' plan to expand its card reach into smaller European markets.
About 18 months ago, the New York-based card giant began partnering with banks in Greece, Portugal, South Korea, Israel, South Africa, and Venezuela to offer American Express cards usable in the local currency.
Other banks in Europe are negotiating with American Express to establish similar relationships, said a spokesman.