WESTLAKE, Texas--(BUSINESS WIRE)--Oct 6, 2025-- The Schwab Trading Activity Index™ (STAX) increased to 46.12 in September, up from its score of 43.69 in August. The only index of its kind, the STAX is a proprietary, behavior-based index that analyzes retail investor stock positions and trading activity from Schwab’s millions of client accounts to illuminate what investors were actually doing and how they were positioned in the markets each month. This press release features multimedia.