What Is the Dow Jones Industrial Average?

• The Dow Jones Industrial Average is a basket of stocks representing the 30 biggest publicly owned companies in the U.S. 
• Performance in the DJIA is closely tied to political and social events. When the COVID-19 pandemic struck in March 2020, for example, the DJIA fell a record 3,000 points.
• Critics of the DJIA argue the index does not represent all publicly traded companies, which at last count was more than 4,000. 

The Dow Jones Industrial Average (DJIA) is a stock market index created by Wall Street Journal editor Charles Dow. Founded on May 26, 1896, the average is named after Dow and statistician Edward Jones. The index shows how 30 large publicly owned U.S. companies have traded during a standard trading session in the stock market.

About 20 of the DJIA's 30 component companies are industrial and consumer goods manufacturers. The others represent industries including financial services, entertainment and information technology. The DJIA is just one of Dow Jones' market indexes.

DJIA history

The DJIA was initially designed to gauge the well-being of the industrial sector with 12 stocks (which eventually increased to 30). These stocks included American Cotton Oil, American Sugar, American Tobacco, National Lead, and the Tennessee Coal, Iron, and Railroad Co.

Although the DJIA debuted on May 26, 1896, it did not appear in the Wall Street Journal regularly until Oct. 7 of the same year. The starting point for the DJIA was 40.94, a far cry from the 13,000-plus point average in October 2012.

At the time, the stock market was not highly regarded or a popular form of investing money. Bonds were the most widely accepted form of investment, as they were backed by real machinery, factories and other tangible assets. The average American was unable to discern whether the stock market was flourishing or perishing. 

Dow created this stock average to help people make sense of the stock market, comparing his average to placing sticks in the beach sand to determine whether the tide was coming in or going out. Rising peaks and troughs meant a bull market, while dropping peaks and troughs indicated a bear market.

Did you know? When the DJIA launched in 1889, it consisted of only 12 companies in the railroad, cotton, sugar, gas, oil and tobacco industries. By 1928, the DJIA grew to include 30 companies, which is where it is today. NASDAQ, a competing index, is largely made up of tech companies.

The DJIA, as well as the rest of the stock market, found itself grossly affected by politics and warfare. A number of global events triggered major changes in the DJIA:

• The fear of World War I caused the suspension of trading for 4.5 months, leading to a DJIA drop of nearly 25% on the day trading reopened.
• In the great stock market crash of 1929 and subsequent Great Depression, the DJIA returned to its starting point, almost 90% below its peak. [Read related article: What Is a Recession?]
• The DJIA dropped 10% during the four-month period in 1956 when Egypt seized the Suez Canal, triggering an invasion from Israel, England and France.
• The Black Monday crash of 1987 brought the DJIA down nearly 508 points, or 22.6%.
• On Sept. 11, 2001, the markets were closed after the terrorist attacks in New York and Washington, D.C. When the markets reopened on Sept. 17, the DJIA dropped nearly 685 points, or 7.13%. Learn how the SBA supported small businesses with access to low-interest loans.
• The biggest drop in the DJIA occurred on March 9, 2020, with the index plunging close to 3,000 points as the COVID-19 pandemic hit U.S. shores. The Dow fell two more times in March. This series of drops was the worst three-point decline in the DJIA's history. 

Did you know? The COVID-19 pandemic sent the Dow Jones Industrial Average plummeting nearly 3,000 points. But it has since recouped those losses and then some. The investors who stayed the course benefited the most. Just ask all those millionaire investors.

How to join the DJIA

When choosing a company to represent an industry in the DJIA, the editors at The Wall Street Journal consider a number of factors. They select companies that represent and lead the market. How long has the company been around? How are shareholders treated? What kind of reputation does the company have in the industry? The Wall Street Journal editors are careful to pick companies that are relevant but not overly trendy. They are looking for staying power in the industry.

An example of the logic used to decide the DJIA companies is when Philip Morris Companies bought out DJIA component General Foods in 1985. The addition of Philip Morris to the DJIA doubled the number of tobacco companies represented, since American Brands was already a component. As a result, the editors dropped American Brands and added McDonald's instead.

How the DJIA works

The DJIA is designed to provide a clear view of the current stock market, which in turn reflects the state of the U.S. economy. The index is calculated by adding the prices of the 30 stocks in the average and dividing by a divisor. The divisor has shrunk over the years to offset arbitrary events like stock splits and roster changes at companies.

The average itself is price-weighted, which means that each company makes up a fraction of the index proportional to its price. With one common divisor, stocks with larger prices have more weight in the index than stocks with lower prices, thus earning the price-weighted index designation. 

While the Dow value is not the actual average of the prices of its component stocks, the formula generates a consistent value for the index. Because the DJIA is made up of large, frequently traded stocks, the price of the DJIA is based on many recent transactions, increasing market indication accuracy. For other indexes, less frequently traded stocks can create a less accurate average.

The DJIA's uses and applications are numerous:

• The DJIA monitors market conditions, enabling investors to identify overall trends and make smarter investment decisions.
• The DJIA can indicate the future performance of stock holdings, mutual funds and exchange-traded funds relative to the performance of the index.
• Because the DJIA has been mapped for so long, investors can study correlations with multiple factors over time.
• As opposed to investing in companies individually, investing directly into the DJIA allows for a diversified portfolio.
• The DJIA can be an effective benchmark to gauge other portfolios and individual investments. A strong portfolio would outperform the DJIA, for example.

Key takeaway: The DJIA was created to give investors a broad view into the U.S. economy, with the 30 stocks representing different areas of the market.

Criticism of the DJIA

There are a number of critics who believe that the inclusion of 30 stocks does not paint an accurate picture of the overall market. With around 4,000 publicly traded companies in the U.S., many believe that the DJIA does not provide a good sample size. Other critics point out that price-weighted indexes also don't consider percentage changes in share prices, which many investors consider important. The DJIA also does not account for stock splits or stock dividends.

Whether or not this criticism is valid, the DJIA is an influential stock market index that many consider to be the most useful market indicator in the U.S.

Elaine J. Hom contributed to the writing and research in this article.