The U.S. Supreme Court on Monday sided with American Express Co and against 11 states, ruling that the company’s policy of forbidding merchants from encouraging customers to use rival credit cards with lower fees does not violate federal antitrust law. Spurning states that had sued American Express, the justices upheld a lower court decision that had cleared the company of unlawfully stifling competition through so-called anti-steering provisions in its contracts with merchants. Shares of American Express moved higher after the ruling and were last up 2.2 percent at $99.41. […]