Fidelity Investments' brokerage assets fell 9% to $1.78 trillion in the third quarter.
The Boston fund company, which had $1.4 trillion of assets in its investment management business as of Sept. 30., said Monday new asset inflows were down by more than half, to $18.4 billion, compared with last year's third quarter.
Other big U.S. brokerages, such as Charles Schwab Corp. and TD Ameritrade Holding Corp., also have been weakened during the financial crisis.