Start here For beginners
How Wall Street Works: The Plumbing Behind Every Trade
What Wall Street actually is, how an order travels from your phone to an exchange and back, who sits on the other side, and how the indices on the evening news are put together.
This section covers the machinery under the market: the exchanges, banks, brokers and regulators that make up Wall Street, the path an order takes from your phone to a matching engine and back, the people who sit on the other side of your fill, and the way the S&P 500 and the Dow are actually put together. Almost none of it is visible from a brokerage app, and almost all of it decides what your trades cost. Once you can picture the route, the rest of the site reads differently.
It is written for beginners. No prior knowledge is assumed and every term is defined the first time it appears. If you have opened a brokerage account and clicked buy without being sure what happened in the next second, start here. Readers who already trade tend to skim the first two guides and slow down at market makers, trading hours and market structure, because those are the pages that explain where money quietly leaks out of a fill.
The guides run in order. The pillar defines the institutions and the difference between the buy side and the sell side. The next guide follows a single order through routing, matching, clearing and T+1 settlement. Market makers explains who fills it and what the spread costs you. Order types hands you the controls, trading hours tells you when to use them, and the IPO and index guides cover where new tickers come from and how the benchmarks are built. Dark pools and Reg NMS close the section at an advanced level.
Everything else on the site sits on top of this. Limit orders and spreads decide what your stock and fund purchases really cost. The auctions at the open and the close shape the candles that technical analysis reads. Index construction is the reason an S&P 500 fund behaves the way it does, which is where the ETF section picks up. Traders come back to these pages once slippage starts showing up in their results.
What Is Wall Street? How the U.S. Financial System Works
A plain map of the U.S. financial system: exchanges, banks, brokers, funds and regulators, what the buy side and sell side actually do, and where your money sits in all of it.
Read the guide →Start with the basics
- beginner
How the Stock Market Works: From Your Order to the Exchange
What actually happens between pressing buy and owning a share. The order book, the matching engine, NYSE versus Nasdaq, and why the money leaves your account a day later.
- beginner
Stock Order Types Explained: Market, Limit, Stop and More
The order type you choose decides whether you control your price or your certainty of getting filled. You cannot have both, and picking the wrong one is expensive in predictable ways.
- beginner
Stock Market Hours: Pre-Market, the Open, the Close and After Hours
The trading day is four different markets wearing one name. What changes in each session, why the closing auction is the most important minute of the day, and where extended hours quietly costs you.
- beginner
Stock Market Indices Explained: S&P 500, Dow and Nasdaq
Three indices, three different rules for turning hundreds of prices into one number. Work through the weighting maths once and the daily headline stops being mysterious.
- beginner
How to Choose a Broker: Fees, Execution and What Matters
The headline commission is zero at almost every US broker now, so the comparison has moved to places the marketing page does not mention. Here is where to look.
Go deeper
- intermediate
Market Makers and Liquidity: Who Is on the Other Side of Your Trade
Someone takes the other side of every trade you make, and they are paid to do it. What a market maker earns, why the spread widens when you most want to sell, and how to measure the toll.
- intermediate
How IPOs Work: From Private Company to Public Ticker
An IPO is a negotiated sale dressed as a market event. Who sets the price, who gets the shares, what the banks are paid, and why the first day you can buy is usually the worst one.
Advanced
How Wall Street Works: common questions
How does the stock market actually work?
Buyers and sellers send orders to exchanges. A matching engine pairs the best bid with the best offer and prints a trade. Your broker routes your order to a venue, the trade is cleared, and shares and cash settle one business day later.
What is the difference between the NYSE and Nasdaq?
The NYSE runs a hybrid model with designated market makers who support the opening and closing auctions. Nasdaq is fully electronic with competing market makers. Both trade under the same national rules, so pricing differences are small.
What is a market maker?
A firm that quotes both a bid and an offer and stands ready to trade either side. It earns the spread between the two and carries the risk of the position. Market makers are why you can sell instantly when no other investor is bidding.
When is the U.S. stock market open?
Regular trading runs from 9:30 a.m. to 4:00 p.m. Eastern on weekdays. Most brokers offer pre-market from 4:00 a.m. and after-hours to 8:00 p.m. Those extended sessions have thinner volume and much wider spreads.
Why does the S&P 500 move differently from the Dow?
The S&P 500 weights companies by market capitalization, so the largest firms drive it. The Dow weights by share price, so a high-priced stock counts for more regardless of company size. The two indices can disagree on any given day.