Many now offer internet trading options. This gives them an incentive to actively trade in your account so they can charge more fees. Unfortunately, this can also lead to high tax bills. Their incentive is thus to grow your assets as quickly and safely as possible. They therefore will use the lowest cost trade executions and use much more of a buy and hold strategy, which lowers the tax bite on you.
Stock exchanges act as auction houses.
They are places to match buyers and sellers. The exchanges do not actually purchase or sell the securities. Specialists match buy and sell orders. There is only one specialist firm for each stock traded at the exchanges. Stocks listed on the NYSE and AMEX may also be traded on one of the five regional exchanges.