The current materiality standard for federal securities fraud is a mid-twentieth-century construct that fails to accommodate certain twenty-first century realities. This Article argues that its reach should be restricted to preserve it for the many circumstances in which it continues to function well. The current standard measures materiality from the standpoint of the reasonable investor, a savvy person who grasps market fundamentals. This standard has a fatal flaw: its inability to protect unsophisticated investors who are duped by implausible falsehoods in inefficient markets. This flaw can no longer be ignored given Internet and telemarketing securities fraud and its many unsophisticated, elderly, and immigrant victims. In recent SEC ...