Stocks, each unit of which is called a share, represent ownership of a company. Stocks, owned either directly or through a mutual fund or ETF, will likely form the majority of most investor’s portfolios. 

Frequently Asked Questions
  • What’s the most expensive stock of all time?

    The most expensive publicly-traded share of stock of all time were the Class A shares of Berkshire Hathaway (BRK.A), Warren Buffet’s conglomerate and holding company as of January 2022. They hit $487,675 per share on Jan 18, 2022. It’s important to remember that this does not mean it is the most valuable company by stock value. The value of a company’s stock, or “market capitalization,” is determined by multiplying the price of its shares by the number of its shares.

  • What is the all time high of the Dow Jones Industrial Average (DJIA)?

    As of early 2022, the all-time closing high of the Dow Jones is 36,799.65 points, which it reached on January 4, 2022. The index’s all-time intraday high was 36,952.65, reached on Jan 5, 2022.

  • What are unrealized gains and losses?

    Unrealized gains or losses represent the amount you would gain or lose if you sold your investment, often a stock, at its current value. You “realize” these gains or losses when you actually sell the investment.

  • What is the difference between preferred stock and common stock?

    When people talk about stocks, they are usually referring to common stock, which is stock that usually gives voting rights in shareholder votes. Preferred stock almost never confers voting rights, but if a company only has enough money to pay some of its dividends, it has to pay preferred stock dividends first. In addition, in the event of a bankruptcy, preferred stockholders have priority over common stockholders on company assets.

  • What’s the difference between cyclical and non-cyclical stocks?

    Cyclical stocks are those that tend to rise and fall with the broader economy, falling when the economy is doing poorly and rising when the economy is doing well. Non-cyclical, often also called defensive stocks, tend have steadier performance that do better when the economy is down are down but peak less high during boom years.

Key Terms
Day Trading Courses
Best Day Trading Courses
Apple's 5 Most Profitable Lines of Business
LUPA Stocks
A paper with interest rates.
Secured Overnight Financing Rate (SOFR) Definition and History
How Prime Day Impacts Amazon's Stock (AMZN)
Close-up of multiple Savings bonds
Common Stock: What It Is, Different Types, vs. Preferred Stock
Preferred vs. Common Stock: What's the Difference?
People floating in currency symbol hot air balloons
Floating Stock: Definition, Example, and Why It's Important
S&P 500 Index
S&P 500 Index: What It’s for and Why It’s Important in Investing
Efficient Market Hypothesis: Is the Stock Market Efficient?
Businessman analyzing report on the tablet.
Cyclical Stock: What It Is, Examples, Risk and Return Potential
Preference Shares: Advantages and Disadvantages
Hand of a Stockbroker Buying and Selling Shares Online
Issued Share vs. Subscribed Share Capital: What's the Difference?
NASDAQ stock market displays at Times Square
What Are the Listing Requirements for the NASDAQ?
Business graph with arrows tending downwards.
Understanding Small-Cap and Big-Cap Stocks
Adjusted Closing Price
Aerial View Of Bulldozer On Sand
Basic Materials Sector: Definition, Examples, and Stocks
Clientele Effect
What Is a Depositary Receipt (DR)? Definition, Types and Examples
Dual Class Stock: Definition, Structure, and Controversy
Mid-Cap: Definition, Other Sizes, Valuation Limits, and Example
Payout concept icon
What Are Preference Shares and What Are the Types of Preferred Stock?
Share Turnover: Definition, What It Signals, Formula, and Example
Cropped Image of Man Checking Stock Market on Mobile Phone
Theoretical Ex-Rights Price – TERP
Stock market data on digital display.
Cyclical vs. Non-Cyclical Stocks: What's the Difference?
Stock market graph chart.
Restricted Shares vs. Stock Options: What's the Difference?
Businessman Show Analyzing Report
What's the Most Expensive Stock of All Time?
Back Stop
Bearer Share: Definition, Example, Risks, and Benefits
CANSLIM Explained: What It Is and How It Works
Image of stock chart on mobile phone
Fractional Share: Definition, Examples, How To Buy & Sell
Businessman grabs head with business chart on screen
October Effect
Shareholder Register
Midsection Businessmen Analyzing Charts on Laptop in Office
Tracking Stock
Porter's 5 Forces on Under Armour
Stock market crash chart on Halloween pumpkin.
October: The Month of Market Crashes?
Businesspeople shaking hands during meeting in conference room
Extraordinary General Meeting (EGM): Definition, Examples, AGM
Buying Stocks Instead of Bonds: Pros and Cons
Building an Effective Watchlist
Midsection Businessmen Analyzing Charts on Laptop in Office
How to Invest in the Nikkei 225
Cheap Stock
Woman looking at her phone while riding an escalator.
Investing $100 a Month in Stocks for 20 Years
Businessmen negotiating in meeting.
What Is a Pure Play?
Does a Stock Dividend Dilute the Price Per Share as Would a Forward Stock Split?
Business Planning
8 Stocks that Benefit from Severe Weather Events
A certificate of preferred stock
Understanding Convertible Preferred Shares
Company Guidance
electronic display of stock tickers and prices
What Is a Stock Ticker? Definition, How They Work, and Origins
Bull and bear, by sculptor Reinhard Dachlauer, in front of the Frankfurt Stock Exchange.
Bond Equity Earnings Yield Ratio (BEER)
Proxy Voting Gives Fund Shareholders a Say
Close up of digital stock market graph
Follow-on Offering (FPO): Definition, 2 Main Types, and Example
Variable Ratio Write
Page Sources
Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. New York Stock Exchange (NYSE). "Berkshire Hathaway, Inc. BRK.A." Accessed Jan. 22, 2022

  2. Yahoo! Finance. "Dow Jones Industrial Average (^DJI). Historical Data." Accessed Jan. 14, 2022.

  3. U.S. Securities and Exchange Commission. "Stocks." Accessed June 28, 2021.