Shearson/American Express Inc. v. McMahon, 482 U.S. 220 (1987), is a United States Supreme Court decision concerning arbitration of private securities fraud claims arising under the Securities Exchange Act of 1934. By a 5–4 margin the Court held that its holding in a 1953 case, Wilko v. Swan, that the nonwaiver provisions of the Securities Act of 1933 prevented the mandatory arbitration of such claims, did not apply to claims under the 1934 Act due to differences in the corresponding language of the two statutes, reversing a decision of the Second Circuit Court of Appeals that had affirmed what had been considered settled law, despite the lack of a precedent. It likewise held that claims under the Racketeer Influenced and Corrupt Organizations Act (RICO) were arbitrable, affirming an order