BRIEF-Massachusetts opens probe into broker-dealer kickbacks; sends inquiry letters to Fidelity, Schwab, Morgan Stanley, others

Aug 15 (Reuters) - MASSACHUSETTS HAS BEGUN AN INVESTIGATORY SWEEP OF BROKER DEALER 'KICKBACKS,' SECRETARY OF THE COMMONWEALTH WILLIAM GALVIN SAYS GALVIN SAYS HE HAS ANNOUNCED AN INVESTIGATION INTO BROKER-DEALER SALES PRACTICES GALVIN SAYS INQUIRY LETTERS HAVE BEEN SENT TO CHARLES SCHWAB, SCOTTRADE, TD AMERITRADE, FIDELITY BROKERAGE SERVICES, E*TRADE, EDWARD D. JONES AND MORGAN STANLEY GALVIN SAYS PROBE TO FOCUS ON PRACTICE OF ROUTING ORDERS TO EXCHANGES THAT OFFER REBATES, AND WHETHER THIS CREAT