American Express has always charged higher fees to its merchants. The reason is that American Express claims its cardholders are wealthier, and it delivers those wealthier customers to the merchants willing to accept Amex and its subsequent higher fees.
Because it charges higher fees than other credit cards, American Express is less competitive. To make up for this, the company prohibits its merchants from suggesting a customer use another card, a practice called “steering” customers to other cards that charge lower fees to the merchant.
The federal government, as well as several states, sued American Express for its anti-steering rules but this week the Supreme Court decided in favor of the company, saying the anti-steering provisions of American Express did not violate federal antitrust law. The court's 5-4 ruling went down predictable ideological lines with conservatives in the majority.
Coincidentally, American Express did act competitively back in March of this year when it reduced the fees it charges merchants to the lowest level they've been in 20 years. It was understood to be the first of several overhauling moves and “conscious tradeoffs” made by Amex's new CEO Stephen Squeri.
Note that American Express lobbyist Andrew Olmem is one of 17 members of the Trump White House to receive waiver certifications which are seen as the exact opposite of Trump's promise to “drain the swamp.”
