Stock
Stock
Quick Definition
A stock (also called a share or equity) is a unit of ownership in a corporation. When you buy a stock, you become a part-owner of that company, with a proportional claim on its assets and earnings. Stocks are bought and sold on stock exchanges like the NYSE and Nasdaq.
What It Means
When a company needs capital to grow, build, or operate, it has two main options: borrow money (issuing bonds or taking loans) or sell ownership stakes (issuing stock). When a company issues stock and makes it available to the public, first through an IPO and then on stock exchanges, anyone can become a partial owner by purchasing shares.
Owning stock means you own a piece of everything the company owns, from its factories and patents to its cash and brand value. In exchange for providing that capital, shareholders can profit in two ways:
- Capital appreciation: The stock price rises and you sell for more than you paid
- Dividends: The company distributes a portion of profits directly to shareholders
Stocks are the primary engine of long-term wealth creation for most investors. The S&P 500 (an index of 500 large U.S. companies) has returned approximately 10% per year on average since 1926, before inflation. After inflation, the real return is roughly 7%.
The bull market that began in October 2022 delivered three consecutive years of double-digit gains. The S&P 500 returned 25.0% in 2024 and 17.9% in 2025 (including dividends), bringing the total return since the October 2022 low to over 100%. The rally was driven heavily by AI-related companies: Nvidia, Meta, Alphabet, Broadcom, and Microsoft accounted for more than half of the S&P 500's total return in 2025.
How It Works
Stock Exchanges
Stocks trade on regulated exchanges during market hours (9:30 AM to 4:00 PM Eastern Time):
| Exchange | Location | Notable Companies |
|---|---|---|
| NYSE (New York Stock Exchange) | New York | Berkshire Hathaway, Walmart, JPMorgan |
| Nasdaq | New York (electronic) | Apple, Microsoft, Nvidia, Amazon |
| NYSE American | New York | Smaller companies |
| OTC Markets | Decentralized | Small-cap, penny stocks |
Stock Price Mechanics
Stock prices are determined by supply and demand between buyers and sellers on the exchange. Prices change continuously during market hours based on:
- Company earnings and forecasts
- Economic news and tariff policy changes
- Investor sentiment
- Industry trends
- Management changes
- Geopolitical events
Types of Stock
Common Stock vs. Preferred Stock
| Feature | Common Stock | Preferred Stock |
|---|---|---|
| Voting rights | Yes (typically 1 vote/share) | Usually no |
| Dividend priority | Paid after preferred | Paid before common |
| Bankruptcy claim | Last in line | Before common, after bondholders |
| Dividend amount | Variable, not guaranteed | Fixed, usually guaranteed |
| Growth potential | Higher | Lower (more bond-like) |
| Who holds it | Retail investors, funds | Institutional investors, sometimes employees |
Growth vs. Value vs. Dividend Stocks
| Category | Characteristics | Examples (2026) |
|---|---|---|
| Growth stocks | High P/E ratios, reinvest earnings, fast revenue growth | Nvidia, Shopify, Palantir |
| Value stocks | Low P/E ratios, undervalued relative to assets/earnings | Bank of America, Ford, Pfizer |
| Dividend stocks | Pay regular dividends, often mature businesses | Johnson & Johnson, Coca-Cola, Realty Income |
| Cyclical stocks | Performance tied to economic cycle | Caterpillar, airlines, homebuilders |
| Defensive stocks | Stable earnings in any economy | Utilities, consumer staples, healthcare |
Stock Valuation: How to Know If a Price Is Fair
Price-to-Earnings (P/E) Ratio
The most common valuation metric:
P/E = Stock Price / Earnings Per Share (EPS)
| P/E Range | Interpretation |
|---|---|
| Under 15 | Potentially undervalued or slow-growth |
| 15-25 | Fairly valued for average-growth company |
| 25-40 | Growth stock premium, high expectations |
| Over 40 | Very high expectations or speculative |
Example: Nvidia trades at approximately $195/share in mid-2026. Earnings per share are estimated at $5.40. P/E = 195/5.40 = 36. This means investors are paying $36 for every $1 of earnings, reflecting expectations of continued AI-driven growth.
Market Capitalization Categories
As of mid-2026, the largest companies by market cap are:
| Category | Market Cap | Example |
|---|---|---|
| Mega-cap | $200B+ | Nvidia ($4.8T), Apple ($4.3T), Alphabet ($4.2T) |
| Large-cap | $10B - $200B | Starbucks, Ford, Delta |
| Mid-cap | $2B - $10B | Crocs, Wingstop, Five Below |
| Small-cap | $300M - $2B | Regional banks, smaller retailers |
| Micro-cap | Under $300M | Very small public companies |
Nvidia became the world's most valuable company in 2025, surpassing Apple and Microsoft, driven by record sales of its AI GPUs. It briefly crossed $5 trillion in market cap in October 2025 before settling back. Apple reclaimed the top spot briefly in July 2026 as investors broadened their focus beyond the most obvious AI beneficiaries.
Real-World Example: The Power of Stock Ownership
Scenario: You invested $10,000 in three companies in 2016. No trading, just held for 10 years.
| Company | 2016 Investment | Approximate Value in 2026 | Return |
|---|---|---|---|
| Nvidia (NVDA) | $10,000 | ~$2,800,000 | +27,000% |
| Apple (AAPL) | $10,000 | ~$72,000 | +620% |
| GE (GE) | $10,000 | ~$18,000 | +80% |
This illustrates both the power of stock ownership and the risk. Not all stocks perform equally. Nvidia's return was extraordinary and driven by the AI revolution, while GE's return was modest after years of restructuring. Diversification across many stocks (through index funds or ETFs) reduces the risk of any single company severely damaging your portfolio.
The Risk Side of Stocks
Stocks carry risks that bonds and savings accounts do not:
| Risk Type | Description | Example |
|---|---|---|
| Market risk | Entire market declines | 2008 financial crisis (-57% from peak) |
| Company risk | Individual company fails | Enron, WorldCom, Lehman Brothers |
| Sector risk | Entire industry declines | Energy stocks in 2015-2016 |
| Liquidity risk | Cannot sell quickly (rare for large stocks) | Micro-cap or OTC stocks |
| Volatility risk | Short-term price swings | 10-15% daily moves in small-caps |
Historical Drawdowns of the S&P 500
| Period | Peak-to-Trough Decline | Recovery Time |
|---|---|---|
| 1929-1932 (Great Depression) | -86% | 25 years |
| 2000-2002 (Dot-com bust) | -49% | 7 years |
| 2008-2009 (Financial Crisis) | -57% | 5 years |
| 2020 (COVID crash) | -34% | 5 months |
| 2025 (Tariff selloff) | -19% | ~4 months |
The 2025 tariff selloff is the most recent example. The S&P 500 dropped sharply in April 2025 when the Trump administration introduced ultra-high "reciprocal" tariffs on dozens of countries. The market then surged nearly 39% from the April low through year end as tariff rates were lowered via trade deals and a temporary truce with China, and AI companies posted strong earnings growth.
Despite these crashes, the long-term trend of U.S. stocks has been upward. Every bear market has eventually been followed by new all-time highs.
Key Points to Remember
- A stock represents partial ownership in a company, with a proportional claim on assets and earnings
- Stocks are historically the highest-returning major asset class over long periods (~10% annually in the U.S.)
- Returns come from capital appreciation (price increases) and dividends (profit distributions)
- Stocks carry significant short-term volatility. Corrections of 10-20% happen regularly, as the 2025 tariff selloff demonstrated.
- Diversification across many stocks dramatically reduces the risk of any single company destroying your portfolio
- Time in the market matters more than timing the market for long-term investors
Common Mistakes to Avoid
- Buying based on recent performance: Last year's best-performing stock is frequently next year's worst. Nvidia's 27,000% decade return is the exception, not the rule.
- Panic-selling during downturns: Selling during a crash locks in losses. The investors who held through the April 2025 tariff selloff recovered within months.
- Concentrating in a single stock: Even great companies can fail or stagnate. No single stock should represent more than 5-10% of most portfolios.
- Ignoring valuation: Buying a great company at an absurd price still leads to poor returns. Price matters.
- Confusing story with value: A compelling company narrative does not guarantee a good stock return. The AI boom has lifted many companies, but not all will sustain their valuations.
Frequently Asked Questions
Q: How do I buy a stock? A: Open a brokerage account (Fidelity, Schwab, Vanguard, or a mobile app like Robinhood), fund it, search for the company by name or ticker symbol, and place a buy order. Market orders execute immediately at the current price. Limit orders let you specify a maximum price. Learn more in our guide on how teenagers can start investing.
Q: Do I need a lot of money to invest in stocks? A: No. Most brokerages now offer fractional shares, meaning you can buy a $0.50 piece of a $500 stock. You can start with as little as $1 at many platforms.
Q: What is the difference between investing and trading? A: Investors buy stocks to hold for years, profiting from business growth. Traders buy and sell frequently to profit from short-term price movements. The data consistently shows that long-term investing outperforms active trading for most people after taxes and transaction costs. Dollar-cost averaging is a strategy that helps investors build positions over time without trying to time the market.
Q: What is a stock ticker symbol? A: A ticker is the unique abbreviation used to identify a company's stock on exchanges. Apple is AAPL, Microsoft is MSFT, Nvidia is NVDA. You use the ticker to look up a stock or place a trade.
Q: What drove the stock market's performance in 2024 and 2025? A: The AI boom was the dominant force. Nvidia, Meta, Alphabet, Broadcom, and Microsoft accounted for more than half of the S&P 500's total return in 2025. Information Technology sector earnings grew 22-29% year-over-year through 2025. Excluding Tech, the rest of the S&P 500 grew earnings by an average of 9.8%. The market also benefited from lower inflation, trade deal resolutions, and strong consumer spending.
Sources: RBC Wealth Management, Visual Capitalist, and Federal Reserve economic research. Past performance does not guarantee future results. Consult a financial advisor for investment decisions.
Related Terms
Preferred Stock
Preferred stock is a hybrid security that combines features of stocks and bonds, offering fixed dividends paid before common stockholders but usually without voting rights, sitting in a middle tier between bondholders and common shareholders.
Common Stock
Common stock represents ownership shares in a company that give investors voting rights and a claim on profits through dividends and price appreciation, the most widely held type of investment security in the world.
Equity
Equity is the ownership value in an asset after subtracting liabilities. Learn about home equity, shareholders equity, and stock market equity with 2026 data.
Capital Gains
Capital gains are the profits earned when you sell an asset for more than you paid for it, taxed at either short-term rates (ordinary income) or preferential long-term rates depending on how long you held the asset.
IPO (Initial Public Offering)
An IPO is the first time a private company sells shares to the public on a stock exchange. In 2025, 202 companies priced IPOs in the US raising $44 billion, and 2026 is expected to see 200 to 230 IPOs with potential blockbuster listings from OpenAI, SpaceX, and others.
Asset Allocation
Asset allocation is the strategy of dividing a portfolio among different asset classes like stocks, bonds, and cash based on your goals, time horizon, and risk tolerance to optimize the risk-return trade-off.
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