What Is a Stock? Definition, Types, and How Stocks Work
Last updated 04/14/2026 by
Ante Mazalin
Edited by
Andrew Latham
Summary:
A stock is a security that represents a fractional ownership stake in a corporation, entitling the holder to a proportional share of the company’s assets and earnings.
Stocks come in two primary forms, each with a different claim on company earnings and different rights for the holder.
- Common stock: The most widely held form — grants voting rights and eligibility for variable dividends, with the highest growth potential but last priority in bankruptcy.
- Preferred stock: Pays a fixed dividend and receives priority over common stockholders in both dividend distributions and liquidation — but typically carries no voting rights.
When a company needs capital to grow, it can borrow money, issue bonds, or sell ownership stakes. Selling ownership stakes — issuing stock — is how most large companies fund expansion without taking on debt.
For investors, stocks are one of the primary vehicles for building long-term wealth. The S&P 500, which tracks 500 large U.S. companies, has returned approximately 10.4% annually on average over the past 100 years, according to Fidelity’s published data — a return that reflects both price appreciation and reinvested dividends.
What owning a stock means
A stockholder owns a slice of the company — its assets, its future earnings, and its liabilities — in proportion to how many shares they hold. That ownership comes with specific legal rights.
For holders of common stock, those rights typically include:
- Voting rights: Shareholders vote on major corporate decisions — including the election of the board of directors, executive compensation packages, and significant mergers or acquisitions. Each share typically equals one vote.
- Dividend eligibility: If the board of directors declares a dividend, common shareholders receive a payment proportional to their holdings. Dividends are not guaranteed — the board can reduce or eliminate them.
- Right to inspect records: Public company shareholders have the right to access certain financial records, including audited statements filed with the Securities and Exchange Commission.
- Residual claim on assets: If the company is liquidated, common shareholders receive whatever is left after all debts and preferred shareholders have been paid — which may be nothing.
Common stock vs. preferred stock
Both types represent ownership, but they behave very differently as investments. The right choice depends on whether you’re prioritizing growth, income, or downside protection.
| Feature | Common Stock | Preferred Stock |
|---|---|---|
| Voting rights | Yes — typically one vote per share | Generally no |
| Dividends | Variable; not guaranteed | Fixed rate; paid before common |
| Priority in bankruptcy | Last in line | Before common; after bondholders |
| Price appreciation potential | High | Limited — behaves more like a bond |
| Who typically holds it | Most individual investors | Income-focused investors, institutions |
Preferred stock is sometimes called a hybrid security because it shares characteristics of both stocks and bonds — it trades on stock exchanges but pays a fixed income stream. Companies often issue it to raise capital without diluting voting control.
How stocks are priced
A stock’s price at any moment is simply what a willing buyer will pay and a willing seller will accept. Underlying that price is the market’s collective estimate of the company’s future earnings, growth prospects, competitive position, and risk.
Several forces shift stock prices in real time:
- Earnings reports: When a company reports quarterly earnings that beat or miss analyst expectations, its stock price typically moves sharply in response.
- Interest rates: Rising interest rates make bonds more attractive relative to stocks and increase borrowing costs for companies, often pushing stock prices down. Falling rates tend to have the opposite effect.
- Economic data: Employment figures, GDP growth, and inflation data signal the direction of the broader economy, affecting investor sentiment across sectors.
- Industry and company news: Product launches, regulatory decisions, leadership changes, and competitive developments all affect how the market values individual companies.
- Supply and demand: If more investors want to buy a stock than sell it, the price rises. More sellers than buyers, and it falls. This basic dynamic plays out in milliseconds on exchanges handling millions of orders per day.
How investors make money from stocks
There are two ways a stock generates a financial return for its owner.
- Capital appreciation: The stock’s price rises above what you paid. You realize that gain when you sell. If you paid $50 per share and sell at $80, your capital gain is $30 per share. Unrealized gains — where the price has risen but you haven’t sold — don’t trigger a tax event.
- Dividends: Some companies distribute a portion of their profits to shareholders on a regular schedule — typically quarterly. Dividend payments are not guaranteed and can be cut or eliminated if the company’s financial position deteriorates. Growth-stage companies often reinvest all earnings rather than paying dividends; established blue-chip companies are more likely to pay them consistently.
Pro tip: Total return — price appreciation plus dividends reinvested — is the figure that matters for long-term wealth building, not price appreciation alone. Reinvesting dividends into additional shares compounds growth significantly over time.
A $10,000 investment in the S&P 500 in 1995 would have grown to more than $190,000 by 2025 with dividends reinvested, according to S&P historical return data.
How stocks are issued and traded
A company first sells stock to the public through an initial public offering (IPO) — the process of listing shares on a stock exchange for the first time. The IPO raises capital directly for the company. Once shares are listed, all subsequent buying and selling happens between investors on secondary markets — the company itself no longer receives proceeds from those trades.
Most U.S. stocks trade on one of two primary exchanges:
- New York Stock Exchange (NYSE): The world’s largest stock exchange by market capitalization, listing approximately 2,800 companies including many of the largest blue-chip corporations.
- Nasdaq: Home to a large share of technology companies; operates as a fully electronic exchange with no physical trading floor.
Stocks that don’t meet exchange listing requirements trade through over-the-counter (OTC) markets — decentralized networks where dealers quote prices directly. OTC stocks carry less regulatory oversight and tend to be less liquid than exchange-listed shares.
The mechanics of buying and selling stocks — order types, brokerage accounts, and trading strategies — are covered in SuperMoney’s entry on stock trading.
Market capitalization: how stocks are categorized by size
Market capitalization (market cap) is the total market value of a company’s outstanding shares — calculated by multiplying the share price by the number of shares. It’s the most common way to classify stocks by company size, and different size categories carry different risk and growth profiles.
| Category | Market Cap Range | Characteristics |
|---|---|---|
| Mega-cap | $200B+ | Global household names (Apple, Microsoft, Amazon); highest liquidity |
| Large-cap | $10B–$200B | Established companies; stable earnings; often pay dividends |
| Mid-cap | $2B–$10B | Growth stage; more volatile than large-cap but more established than small-cap |
| Small-cap | $300M–$2B | Higher growth potential; higher risk; less analyst coverage |
| Micro-cap | $50M–$300M | Early-stage or niche companies; lowest liquidity; highest risk |
The S&P 500 tracks the 500 largest U.S. companies by market cap. The Dow Jones Industrial Average tracks 30 mega-cap blue-chip stocks. Together these indexes serve as the most widely referenced benchmarks for U.S. stock market performance.
Risks of owning stocks
Stocks offer higher long-term return potential than most other asset classes — but that potential comes with real risk. Understanding each type helps you assess what you’re actually taking on.
- Market risk: The overall market can decline regardless of individual company performance. During the 2008 financial crisis, the S&P 500 fell more than 38% in a single year. During the 2020 COVID crash, it fell roughly 34% in five weeks before recovering.
- Company-specific risk: A single company can fail entirely even when the broader market is healthy. Individual stock investors face the additional risk that their chosen company underperforms — or goes bankrupt. Diversification across many stocks reduces but does not eliminate this risk.
- Liquidity risk: Large-cap stocks on major exchanges are highly liquid — you can sell instantly at the current price. Smaller or OTC-traded stocks may be harder to sell quickly without moving the price.
- Volatility risk: Stock prices fluctuate daily, sometimes dramatically. Investors with short time horizons who may need to sell during a downturn are more exposed to this risk than long-term investors who can wait for recovery.
- Concentration risk: Holding too much of a single stock — especially an employer’s stock — creates outsized exposure to one company’s fortunes.
Stocks vs. other investments
Stocks are one piece of a broader investment landscape. Understanding how they compare to other core asset classes clarifies where they fit in a portfolio.
- Stocks vs. bonds: Bonds are debt instruments — you lend money and receive fixed interest. Stocks represent ownership. Stocks have historically delivered higher long-term returns; bonds offer more stability and priority over stockholders in bankruptcy.
- Stocks vs. mutual funds: A mutual fund pools money from many investors to buy a basket of stocks (or other securities). Buying a mutual fund gives instant diversification; buying individual stocks does not.
- Stocks vs. index funds: An index fund is a type of mutual fund or ETF that passively holds all the stocks in a given index. Rather than picking individual stocks, index fund investors own a proportional slice of the entire index.
Key takeaways
- A stock is a fractional ownership stake in a corporation — holders are entitled to a proportional share of its assets and earnings, along with voting rights (common stock) or fixed dividends with liquidation priority (preferred stock).
- Stock prices are set by supply and demand and are driven by earnings expectations, interest rates, economic data, and company-specific news.
- Investors earn returns through capital appreciation (selling at a higher price than they paid) and dividends (periodic profit distributions). Total return — appreciation plus reinvested dividends — is the most meaningful measure of long-term stock performance.
- Stocks trade on exchanges like the NYSE and Nasdaq after an IPO; all post-IPO trades happen on secondary markets between investors — the company doesn’t receive proceeds.
- Market capitalization classifies stocks from micro-cap (smallest, highest risk) to mega-cap (largest, most liquid) — each category carries a different return and volatility profile.
- Stocks carry market risk, company-specific risk, liquidity risk, and concentration risk; diversification through mutual funds or index funds reduces but does not eliminate these risks.
Frequently asked questions
What is the difference between a stock and a share?
The terms are used interchangeably. “Stock” usually refers to equity ownership in general — you own “stock” in a company. “Share” refers to a specific unit of that ownership — you own 50 “shares” of a company. Saying you “own stock in Apple” and saying you “own shares of Apple” mean the same thing.
Do you have to buy a whole share of stock?
Not at most major brokerages. Fractional shares allow investors to buy a dollar amount of stock regardless of the share price. If a stock trades at $500 per share, you can buy $50 worth — owning one-tenth of a share and receiving dividends proportionally.
What happens to your stock if a company goes bankrupt?
Common stockholders are last in the repayment hierarchy. In a bankruptcy, the company’s assets are used to pay secured creditors, then unsecured bondholders, then preferred stockholders. Common stockholders receive whatever is left — which is usually nothing. This is why diversification across many companies matters: one company going bankrupt in a broad portfolio has a limited impact.
What is a stock split?
A stock split increases the number of shares outstanding while proportionally reducing the price per share. A 2-for-1 split doubles the number of shares and halves the price — you own twice as many shares, but each is worth half as much. Total value is unchanged. Companies split their stock to keep the price accessible to more investors.
How are stocks taxed?
In a taxable account, gains from selling stock are taxed as capital gains — at a lower long-term rate (0%, 15%, or 20% depending on income) if you held the stock for more than one year, or at ordinary income rates if you held it for one year or less. Dividends are taxed as ordinary income or at qualified dividend rates, depending on the holding period and type of dividend. In a 401(k) or IRA, stock gains are tax-deferred or tax-free.
What is the difference between stocks and the stock market?
A stock is an individual security — a ownership stake in one company. The stock market is the collective system of exchanges and platforms where stocks are issued, bought, and sold. Owning stocks means owning individual securities; investing “in the stock market” typically means gaining broad exposure to many stocks through an index fund or mutual fund.
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