Freedom isn’t free, and free trades aren’t either.

Charles Schwab Corp. shook the brokerage industry this week when it said it will cut commissions to zero on Oct. 7. Schwab’s move, which followed a similar cut by Interactive Brokers Group Inc. and has already been matched by rivalsTD Ameritrade Holding Corp. and E*Trade Financial Corp., is likely to be copied by other big brokers.

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