Exchanges & Market Plumbing

How orders travel, clear and settle.

1. How Exchanges Work — Stock exchanges match buyers and sellers under strict rules. Here is how today’s electronic exchanges work, who owns them, how prices are protected across venues and what happens when markets move too fast.
2. Market Makers and Specialists — Market makers stand ready to buy and sell all day, earning the bid-ask spread in exchange for providing liquidity. Here is how they work, what happened to the old floor specialists and why spreads matter to you.
3. Dark Pools — Dark pools are private trading venues that do not show their orders publicly. They help big investors trade without moving prices. Here is how they work, how much trading happens off-exchange and the debate around them.
4. Payment for Order Flow — Many zero-commission brokers are paid by market makers to send them customer orders. Here is how payment for order flow works, how it affects your trades and why Europe banned it while the U.S. still allows it.
5. Clearing & Settlement — After a trade, the shares and cash still have to change hands. Clearing and settlement make sure they do, even if one side fails. Here is how the process works and why U.S. stocks now settle in one business day.
6. Global Exchanges and Trading Hours — Markets open and close around the world in sequence, from Tokyo to London to New York. Here are the main trading hours, how extended sessions work and the planned move toward nearly round-the-clock U.S. trading.