Kaiser Aluminum sued the Frates group.

The suit filed in U.S. District Court charges a group led by Oklahoma investor J. A. Frates with various securities violations, “including material omissions and false and misleading statements” in documents it filed with the SEC. The Frates group is attempting a $20-per-share hostile takeover of Kaiser Aluminum & Chemical. The suit seeks restraints against further purchases of Kaiser stock by the group and “divestiture of shares purchased after the misleading documents were filed,” the Oakland-based company said in a statement.