The exchange may offer privileged services like high-frequency trading to larger clients like mutual funds and asset management companies (AMC), and earn money accordingly. There are provisions for regulatory fee and registration fee for different profiles of market participants, like the market maker and broker, which form other sources of income for the stock exchanges.
The stock exchange shoulders the responsibility of ensuring price transparency, liquidity, price discovery and fair dealings in such trading activities. As almost all major stock markets across the globe now operate electronically, the exchange maintains trading systems that efficiently manage the buy and sell orders from various market participants. They perform the price matching function to facilitate trade execution at a price fair to both buyers and sellers.
For example, there may be three buyers who have placed orders for buying Microsoft shares at $100, $105 and $110, and there may be four sellers who are willing to sell Microsoft shares at $110, $112, $115 and $120. The exchange (through their computer operated automated trading systems) needs to ensure that the best buy and best sell are matched, which in this case is at $110 for the given quantity of trade.
When you buy a stock, you should have a good reason for doing so and an expectation of what the price will do if the reason is valid. At the same time, you should establish the point at which you will liquidate your holdings, especially if your reason is proven invalid or if the stock doesn’t react as expected when your expectation has been met. In other words, have an exit strategy before you buy the security and execute that strategy unemotionally.
Such dedicated markets serve as a platform where numerous buyers and sellers meet, interact and transact. Since the number of market participants is huge, one is assured of a fair price. For example, if there is only one seller of Christmas trees in the entire city, he will have the liberty to charge any price he pleases as the buyers won’t have anywhere else to go. If the number of tree sellers is large in a common marketplace, they will have to compete against each other to attract buyers. The buyers will be spoiled for choice with low- or optimum-pricing making it a fair market with price transparency. Even while shopping online, buyers compare prices offered by different sellers on the same shopping portal or across different portals to get the best deals, forcing the various online sellers to offer the best price.