Now the online broker is an uptown Manhattan-based financial firm in merger talks with rival Ameritrade . A merger of E-Trade, with 4.7 million brokerage and banking accounts, and Omaha-based Ameritrade, with 6.3 million, would create a firm that supplants San Francisco-based Charles Schwab's 6.9-million accounts as the online leader. Schwab's stock also ticked upward amid speculation that consolidation would allow firms to raise fees.