U.S. Files Antitrust Suit Against AmEx

At issue are the varied processing fees that the card companies charge merchants when customers use different cards. Cards that offer rewards such as airline miles cost merchants more, and merchants who agree to accept a company's cards must accept all of them.

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As a civil case, the settlement isn't likely to involve any financial penalties for the companies...

I like Amex a lot, and a lot of what I like about them is the club they very overtly wield with merchants. It's the card I feel safest using.