Drafters of the Private Securities Litigation Reform Act of 1995 reunited this week to file an amicus brief in Halliburton v. Erica P. John Fund Inc., one of the most important business cases now before the U.S. Supreme Court. Halliburton could severely undermine securities class actions by abolishing a plaintiffs-friendly legal doctrine known as the fraud-on-the-market theory. The new brief could be bad news for securities plaintiffs lawyers, because it tries to preemptively dismantle one argument for keeping the doctrine intact.

A group of 12 former legislators, government lawyers, and U.S. Securities and Exchange Commission officials filed the 36-page brief on Monday. The group includes Alfonse D’Amato, a former U.S. senator who introduced the Senate version of the PSLRA; Christopher Cox, a partner at Bingham McCutchen and a former U.S. congressman who introduced the House version of the PSLRA; and Sullivan & Cromwell partner Robert Giuffra Jr., who cowrote the PSLRA in his prior role as chief counsel for the Senate Committee on Banking, Housing and Urban Affairs. Giuffra filed the brief along with Sullivan & Cromwell colleague Jeffrey Wall.