The stock market is the network of regulated exchanges where investors buy and sell shares of publicly traded companies, with prices set moment to moment by what buyers will pay and sellers will accept. In the United States, the two largest venues, the New York Stock Exchange and Nasdaq, together list thousands of companies worth tens of trillions of dollars. The market does two jobs at once: it lets companies raise money by selling ownership stakes to the public, and it gives investors a place to trade those stakes afterward.
What You Actually Own When You Buy a Share
A share of stock is a small piece of a company. If a corporation has issued 10 million shares and you hold 1,000 of them, you own one ten-thousandth of the business. That slice gives you a proportional claim on the company’s profits and, if the company is ever dissolved, whatever assets remain after debts are paid.
Ownership also carries governance rights. Public companies must follow federal rules when asking shareholders to vote on major decisions like electing board members or approving mergers, and those rules require the company to send you a proxy statement explaining what you are voting on.1Office of the Law Revision Counsel. 15 U.S.C. 78n – Proxies Most shares are common stock, which typically carries one vote per share. Preferred stock is the other main type: preferred shareholders usually get dividends first and have a higher claim on assets in a liquidation, but they often give up voting rights for that priority.
Dividends are the most visible financial benefit of ownership. When a company earns a profit and decides to distribute some of it, each shareholder gets a payment based on how many shares they hold. Not every company pays dividends. Many fast-growing firms reinvest all their earnings instead. For those that do pay, dividends can supply steady income on top of any gain from the stock’s price rising over time.
Where Trades Happen
Exchanges are the marketplaces where stock trades actually clear. Before a stock can trade on one, the exchange must register with the Securities and Exchange Commission under federal law and maintain rules designed to prevent fraud, promote fair trading, and protect investors.2Office of the Law Revision Counsel. 15 U.S.C. 78f – National Securities Exchanges The NYSE uses an auction model where designated market makers help match buyers and sellers, while Nasdaq runs a dealer network where trades happen electronically between competing participants. For an individual investor, the difference rarely matters: your brokerage routes your order to whichever venue offers the best price, and federal rules require trading centers to prevent “trade-throughs” so your order should execute at the best available price across all exchanges.3eCFR. 17 CFR 242.611 – Order Protection Rule
Trading Hours and Settlement
The core trading session on both major exchanges runs from 9:30 a.m. to 4:00 p.m. Eastern Time, Monday through Friday, excluding market holidays.4NYSE. Holidays and Trading Hours Several NYSE platforms also offer extended sessions, with early trading starting as early as 7:00 a.m. ET and late trading running until 8:00 p.m. ET. Extended-hours trading has thinner volume and wider price spreads, so execution is usually less favorable than during the core session.
When you buy or sell, the trade settles under a T+1 rule: the actual transfer of shares and cash happens one business day after the trade date.5eCFR. 17 CFR 240.15c6-1 – Settlement Cycle This shortened cycle took effect on May 28, 2024, replacing the previous T+2 standard.6U.S. Securities and Exchange Commission. Shortening the Securities Transaction Settlement Cycle Your brokerage handles all of this in the background, but the timeline matters if you are selling shares and need the cash for another purchase.
How Companies Get Onto the Market
A company first sells stock to the public through an initial public offering, or IPO. This happens in what is called the primary market, and it is the only time the company itself receives money from the sale of its shares. Before the IPO can proceed, the company must file a registration statement (Form S-1) with the SEC, disclosing its finances, business model, and the risks an investor would face.7eCFR. 17 CFR Part 239 – Forms Prescribed Under the Securities Act of 1933 The prospectus that results from that filing is the single most useful document for a potential IPO investor to read, because it is where the company has to be honest about what could go wrong.
Investment banks act as underwriters, buying the shares from the company and reselling them to institutional and retail investors. Underwriters charge a gross spread that averages between 4% and 7% of the total capital raised, with the percentage tending toward 7% for offerings under $200 million and dropping closer to 4% to 5% on billion-dollar deals. Those fees come out of the company’s IPO proceeds.
Everything after the IPO happens on the secondary market: the everyday buying and selling reported on financial news. The company itself is not involved in these transactions. When you buy 50 shares through your brokerage app, you are buying them from another investor who decided to sell, and the company’s bank account does not change by a penny.
How Buying and Selling Actually Works
Every stock has two prices at any given moment. The bid is the highest price someone is currently willing to pay. The ask is the lowest price someone is currently willing to accept. The gap between them is the spread, and it is a real cost to you. A stock with a bid of $49.95 and an ask of $50.00 has a five-cent spread, so you would lose five cents per share by buying and immediately selling. Heavily traded stocks from large companies tend to have very tight spreads, sometimes just a penny. Thinly traded stocks can have spreads wide enough to matter.
Order Types
How you place your order determines how much control you have over the price:
- Market order: Executes immediately at the best available price. You are guaranteed to get the trade done, but in a fast-moving market the price can shift between when you click “buy” and when the order fills.8Investor.gov. Types of Orders
- Limit order: Executes only at your specified price or better. A buy limit at $48 will not fill unless the price drops to $48 or below. The trade-off is that if the stock never hits your price, the order never executes.8Investor.gov. Types of Orders
- Stop order: Triggers a market order once the stock hits a specified price. Investors often use these to limit losses, for example placing a stop at $45 on a stock bought at $50. In a sharp drop or an overnight gap, the actual execution can come in well below the stop price, because the order converts to a market order once triggered.
For most long-term investors, market orders on liquid stocks work fine. Limit orders become more useful when you are trading less popular stocks with wider spreads or trying to buy at a specific price during volatility.
What Moves Prices
Stock prices move because the balance between buyers and sellers keeps shifting. Positive quarterly earnings, a new product launch, or an industry tailwind brings in more buyers and pushes prices up. Disappointing results, regulatory trouble, or rising interest rates can tip the balance the other way. Interest rate changes from the Federal Reserve carry outsized weight because they change the math on how much future profits are worth today: when rates rise, future earnings are worth less in present terms, which tends to pull stock prices down across the board.
Reading “The Market” Through Indices
When financial news says “the market” was up or down, that shorthand usually refers to one of a few major indices, statistical measures that track groups of stocks as a proxy for the broader economy.
The S&P 500 tracks 500 large U.S. companies using a float-adjusted capitalization weighting, so companies with a larger total market value have more influence on the index’s daily movement. A 2% swing in a $3 trillion company moves the S&P 500 far more than the same swing in a $30 billion company. Because it covers roughly 80% of the total U.S. stock market’s value, the S&P 500 is the benchmark most professional fund managers measure themselves against.
The Dow Jones Industrial Average takes a different approach. It tracks only 30 blue-chip companies and uses price weighting, so stocks with higher share prices have more impact regardless of the company’s overall size. A $400 stock moves the Dow twice as much as a $200 stock even if the cheaper company is worth more. This makes the Dow a less precise indicator than the S&P 500, though it remains the most widely quoted index in media coverage.
For an individual investor, indices are most useful as benchmarks. If the S&P 500 gained 12% last year and your portfolio gained 8%, you underperformed the broad market. Index-tracking exchange-traded funds let you invest in an entire basket with a single purchase, which is why they have become a default recommendation for people who do not want to pick individual stocks.
The Protections Around You
The regulatory framework around the stock market exists because history has repeatedly shown what happens without it. Several layers of protection are worth knowing before you put money in.
SEC and FINRA Oversight
The SEC oversees the markets at the federal level, requiring public companies to disclose their financial condition and prohibiting fraud, insider trading, and market manipulation. The Financial Industry Regulatory Authority operates as a self-regulatory organization under SEC supervision, directly overseeing broker-dealer firms and their employees. FINRA inspects its member firms at least every four years, and as often as annually for higher-risk firms, checking for compliance with securities laws.9FINRA. What It Means to Be Regulated by FINRA
Regulation Best Interest
When a broker recommends a stock or investment strategy, federal rules require them to act in your best interest rather than simply suggest something “suitable.” Regulation Best Interest requires brokers to disclose conflicts of interest, exercise reasonable care in their recommendations, and maintain policies to manage situations where their financial incentives might conflict with your goals. If your broker gets a bigger commission for selling you Fund A over Fund B, they must disclose that and still show that Fund A is genuinely in your best interest.
SIPC Protection
The Securities Investor Protection Corporation protects you if your brokerage firm fails financially. It does not cover investment losses, only the risk of the firm itself going under and taking your assets with it. SIPC restores securities and cash in your account up to $500,000, with a $250,000 limit on the cash portion.10SIPC. What SIPC Protects Think of it as the brokerage equivalent of FDIC insurance. It will not help you if your stocks lose value.
Circuit Breakers
Exchanges use market-wide circuit breakers to pause trading when prices fall too fast, giving participants time to absorb information rather than panic-sell. The triggers are based on the S&P 500’s decline from its previous closing price:
- Level 1 (7% drop): Trading halts for at least 15 minutes.
- Level 2 (13% drop): Trading halts for at least 15 minutes.
- Level 3 (20% drop): Trading halts for the rest of the day.11NYSE. Market-Wide Circuit Breakers FAQ
Level 1 breakers have tripped multiple times in recent decades, most notably during the early days of the COVID-19 sell-off in March 2020. Level 3 has never been triggered under the current percentage thresholds.
Pattern Day Trader Rule
If you execute four or more day trades within five business days, and those trades represent more than 6% of your total activity in a margin account during that period, your broker will flag your account as a pattern day trader. Once flagged, you must maintain at least $25,000 in equity in your account and can only trade in a margin account.12Investor.gov. Pattern Day Trader This rule catches a lot of new investors off guard. If your account drops below $25,000, the broker will restrict your trading until you top it back up.
What Taxes Do to Your Returns
Taxes are the cost most new investors underestimate. Every sale of stock at a profit creates a taxable event, and the rate you pay depends almost entirely on how long you held the shares.
Short-Term vs. Long-Term Capital Gains
Profits on stocks held for one year or less are short-term capital gains, taxed at your ordinary income tax rate, which in 2026 ranges from 10% to 37% depending on your total taxable income. Profits on stocks held for more than one year qualify as long-term capital gains, which are taxed at significantly lower rates.13Office of the Law Revision Counsel. 26 U.S.C. 1222 – Other Terms Relating to Capital Gains and Losses
For 2026, the long-term capital gains rates are:
- 0%: Single filers with taxable income up to $49,450 (up to $98,900 for married filing jointly).
- 15%: Single filers from $49,451 to $545,500 ($98,901 to $613,700 married filing jointly).
- 20%: Single filers above $545,500 (above $613,700 married filing jointly).
The gap matters. Sell a stock at a $10,000 profit after 11 months and you might owe $2,200 to $3,700 in federal tax. Wait one more month and that same profit could be taxed at 0% or 15%. This is the single most controllable tax variable for most stock investors.
Net Investment Income Tax
High earners face an additional 3.8% surtax on net investment income, which includes capital gains and dividends. The tax applies when modified adjusted gross income exceeds $200,000 for single filers or $250,000 for married couples filing jointly.14Internal Revenue Service. Net Investment Income Tax Those thresholds are not adjusted for inflation, so more taxpayers cross them each year.
Dividend Taxes
Dividends come in two forms for tax purposes. Qualified dividends are taxed at the same lower rates as long-term capital gains: 0%, 15%, or 20%. To qualify, you must hold the dividend-paying stock for at least 61 days during the 121-day period that starts 60 days before the ex-dividend date (the first day a buyer will not receive the upcoming dividend). Dividends that do not meet this holding requirement are taxed as ordinary income at your full rate.
Capital Losses and the Wash Sale Rule
When you sell a stock at a loss, you can use that loss to offset capital gains dollar for dollar. If your losses exceed your gains in a given year, you can deduct up to $3,000 of the excess against your ordinary income ($1,500 if married filing separately) and carry any remaining losses forward to future years.15Office of the Law Revision Counsel. 26 U.S.C. 1211 – Limitation on Capital Losses
There is a trap. If you sell a stock at a loss and buy the same or a substantially identical stock within 30 days before or after the sale, the IRS disallows the loss under the wash sale rule.16Internal Revenue Service. Wash Sales The disallowed loss gets added to the cost basis of the replacement shares, so the tax benefit is not gone forever, but you cannot claim it now. Investors who sell a losing position and immediately buy it back thinking they have locked in a tax loss are the ones this rule catches most often.