Amex is accusing the two major card associations of acting as a cartel to block its access to banks. The move follows a US Supreme Court ruling that the credit card associations had breached enforcement rules by barring so-called “member” banks from issuing rival cards.

Last month, Morgan Stanley’s Discover credit card unit launched a similar lawsuit against Visa and Mastercard, seeking unspecified damages. Until the Supreme Court ruling, Discover and American Express had been unable to issue cards through banks because Visa and MasterCard would not allow their member banks to do this.

Kenneth Chenault, American Express chief executive said the Visa and MasterCard system severely impeded business. The eight banks were named in the suit because they had been or are members of one or both credit card associations’ boards of directors.

Noah Hanft, chief counsel at MasterCard, said: “American Express will need to prove that it was injured and suffered damages as a result of MasterCard’s policy – claims that the reality of the marketplace demonstrate are unfounded.” Visa also vowed to fight the lawsuit.

Of the eight banks named, JPMorgan, US Bancorp, Household Bank, Providian, Capital One, and Wells Fargo declined to comment. Bank of America and USAA Federal Savings Bank did not return calls.

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