Last February, when Chief Justice John Roberts and Justice Samuel Alito of the U.S. Supreme Court sided with the court’s liberal wing in Amgen v. Connecticut Retirement Plans, they joined an opinion that left intact the standard for certification of a class of securities fraud plaintiffs. Amgen, as you probably recall, had asked the court to impose a requirement that shareholders prove the materiality of supposed corporate misrepresentations in order to win class certification. The majority refused, in a decision written by Justice Ruth Ginsburg. Among other things, Justice Ginsburg said that if Congress had wanted to tinker with the Supreme Court’s 1988 precedent on securities class certification, Basic v. Levinson, it could have done so in 1995, when lawmakers passed the Private Securities Litigation Reform Act, or again in 1998, when the Securities Litigation Uniform Standards Act became law. Instead, Justice Ginsburg wrote in Amgen, “Congress rejected calls to undo the fraud-on-the-market presumption of classwide reliance endorsed in Basic.”