What Is the Dow Jones Industrial Average?

Key Takeaways:

• The Dow Jones Industrial Average tracks 30 large U.S. companies and has been calculated continuously since 1896
• It uses a price-weighted methodology, meaning companies with higher share prices have more influence on the index regardless of their total market value
• Because of price-weighting, a company with a high share price can have more influence on the Dow than a much larger company by market value
• The Dow is maintained by S&P Dow Jones Indices and its components are selected by committee, not by strict quantitative rules
• Unlike the S&P 500 and Nasdaq Composite, the Dow excludes transportation and utility companies, which are tracked by separate indexes
• The Dow is narrower than the S&P 500, which tracks 500 companies, and the Nasdaq Composite, which tracks thousands

Most people have heard of the Dow Jones. Fewer know exactly what it measures or why its methodology makes it genuinely different from every other major index.

The Dow Jones Industrial Average, commonly called the Dow or the DJIA, tracks 30 large, publicly traded companies listed on U.S. stock exchanges. Unlike the S&P 500 and the Nasdaq Composite, which weight their components by market capitalization, the Dow uses a price-weighted methodology. Companies with higher share prices carry more influence over its movements regardless of their total market value. That single methodological difference shapes everything about how the Dow behaves and what it actually represents.

A Brief History of the Dow Jones

Charles Dow, co-founder of The Wall Street Journal and Dow Jones and Company, first calculated the index on May 26, 1896, alongside his business associate Edward Jones. The original version covered 12 companies, primarily in industrial sectors such as agriculture, coal, oil, and steel.

Over time, the composition shifted to reflect changes in the U.S. economy, eventually expanding to the current 30 companies. S&P Dow Jones Indices now maintains the index, and its components span technology, healthcare, retail, and financial services.

How Is the Dow Jones Calculated?

The Dow is a price-weighted index. Each component's influence is determined by its share price, not by the total market value of the company.

In practice, a stock trading at a higher price moves the index more than a stock trading at a lower price, even if the cheaper company is far larger by market capitalization. Goldman Sachs, for example, has historically carried more influence on the Dow than Apple, despite Apple being significantly larger by total market value, according to S&P Dow Jones Indices. Most investors find that counterintuitive the first time they hear it.

The index value is calculated by adding the share prices of all 30 components and dividing by a figure called the Dow Divisor. S&P periodically adjusts the Divisor to account for corporate events such as stock splits, spinoffs, and changes in composition, keeping the index level consistent through structural changes.

What Companies Are in the Dow Jones?

A committee at S&P Dow Jones Indices selects the 30 Dow components. Unlike the S&P 500, which applies defined quantitative criteria, the Dow's selection process is not governed by strict rules. The committee weighs a company's reputation, history of sustained growth, and relevance to the broader U.S. economy.

Despite the name, the Dow is no longer limited to industrial companies. Its current composition spans a wide range of sectors. By design, it excludes transportation and utility companies, which are tracked separately by the Dow Jones Transportation Average and the Dow Jones Utility Average.

With only 30 components, the Dow is a narrower measure than either the S&P 500 or the Nasdaq Composite. Its members are typically large, well-established blue-chip stocks with long operating histories.

What companies are in the Dow Jones

The 30 companies in the Dow Jones Industrial Average are selected by a committee at S&P Dow Jones Indices. Unlike the S&P 500, which uses defined quantitative criteria for inclusion, the Dow's selection process is not governed by strict rules. The committee focuses on a company's reputation, its history of sustained growth, and its relevance to the broader U.S. economy.

Despite its name, the Dow is no longer limited to industrial companies. Its current composition includes companies from a wide range of sectors. However, by design, the index excludes transportation and utility companies, which are tracked by separate Dow Jones indexes, the Dow Jones Transportation Average and the Dow Jones Utility Average.

Because only 30 companies are included, the Dow is a narrower measure of the market than either the S&P 500 or the Nasdaq Composite. Its components are typically large, well-established companies, often referred to as blue-chip stocks, with long track records of operation.

The Dow vs. other major indexes

The Dow Jones Industrial Average is one of three indexes most commonly cited when discussing U.S. stock market performance. Its methodology and composition set it apart from the other two in important ways.

The S&P 500 is generally considered the most representative benchmark of the U.S. equity market, given its broader scope and market-cap weighting.

The Nasdaq Composite serves as the primary benchmark for the technology sector. All three indexes serve as the basis for a range of index funds and ETFs that allow investors to gain exposure to their constituent companies.

The Dow, by contrast, offers a narrower but historically significant snapshot of large U.S. companies, one that has been tracked continuously for well over a century.

Why Do Investors Still Follow the Dow Jones?

Longevity matters in markets. The Dow provides a continuous record of U.S. equity performance stretching back to 1896, which no other major index can match. That makes it a genuine reference point for understanding long-term market trends.

Its 30 components are among the most recognised companies in the U.S. economy, and financial media frequently use daily Dow movements as a quick proxy for overall market sentiment. For that reason, knowing what the Dow measures, and what it does not, is as useful as knowing the number itself.

Is the Dow Jones a Good Measure of the Stock Market?

Critics make a reasonable case against it. Thirty companies is a narrow sample of an economy with thousands of publicly traded businesses across every sector.

Price-weighting compounds the problem. A company with a high share price can move the index significantly regardless of how large or economically relevant it actually is. Market-cap-weighted indexes like the S&P 500 correct for this by measuring the actual total market value of each company.

The selection process adds subjectivity. Components are chosen by a committee using editorial judgment, not objective quantitative criteria. That means inclusion reflects opinion as much as market standing.

For those reasons, most investors and analysts prefer the S&P 500 as a broader, more representative benchmark. The Dow's defence is the one thing no newer index can replicate: an uninterrupted record since May 26, 1896.

Conclusion

The Dow Jones Industrial Average is a price-weighted index of 30 large U.S. companies, first calculated in 1896 and maintained today by S&P Dow Jones Indices. Its price-weighted methodology distinguishes it from the market-cap-weighted S&P 500 and Nasdaq Composite. With only 30 components, it is a focused rather than comprehensive measure of U.S. equity performance. It has been calculated continuously since May 26, 1896.