What Is the Dow Jones Industrial Average? Guide

Turn on the evening news and you’ll hear it almost every night: “The Dow closed up 200 points today.” But what is that number actually measuring, and should it change how you think about your own investments?

The Dow Jones Industrial Average, often shortened to “the Dow” or “the DJIA,” is one of three major U.S. stock market indexes, alongside the S&P 500 and the Nasdaq Composite. It’s also the oldest of the three by a wide margin. Understanding what it tracks, how it’s built, and where it falls short can help you read market headlines with more confidence instead of just nodding along.

What Is the Dow Jones Industrial Average?

The DJIA is a stock market index made up of 30 large, publicly traded U.S. companies. It was created in 1896 by journalist Charles Dow and statistician Edward Jones, and today it’s maintained by S&P Dow Jones Indices, a division of S&P Global. Alongside the S&P 500 and the Nasdaq 100, it’s one of the indexes market participants watch most closely, since all three track companies affected by the same business cycle and broader economic forces.

Each of the 30 companies in the Dow is considered a “blue chip,” meaning it has an established reputation, a long track record, and a large enough footprint to matter to the wider economy. Apple, Coca-Cola, Microsoft, and Visa are current examples. The list changes occasionally as the economy shifts, but slowly. It’s not the kind of index that gets rebalanced every quarter.

A Short History: From 12 Stocks to 30

The Dow didn’t start out looking anything like it does now.

1896: Charles Dow launched the index with just 12 companies, mostly involved in railroads and heavy industry, including names like General Electric and American Cotton Oil.
1928: The index expanded to 30 companies, the number it still uses today.
1999: Microsoft joined, marking the Dow’s first real move into technology.
2018: General Electric, the last original component still in the index, was removed after more than a century.
2020: Salesforce, Amgen, and Honeywell replaced ExxonMobil, Pfizer, and Raytheon in one of the more significant reshuffles in recent years.

None of the original 12 companies remain in today’s Dow. That alone says something: the index isn’t a fixed snapshot of American industry; it’s a moving one, updated every so often to reflect which sectors carry the most economic weight.

How the Dow Is Calculated (It’s Not a Simple Average)

Here’s where a lot of people get tripped up. The name says “average,” and technically it started as one, but the modern calculation is more involved.

The DJIA is a price-weighted index. That means a company’s stock price, not its overall size or market value, determines how much influence it has on the index. A $500 stock moves the Dow more than a $50 stock, even if the $50 stock belongs to a company worth far more overall.

To calculate the index, you add up the share prices of all 30 companies, then divide by a number called the Dow Divisor. That divisor isn’t a round number; it currently sits at roughly 0.152, and it gets adjusted whenever something like a stock split happens, so the index value doesn’t jump around for reasons that have nothing to do with actual company performance.

This price-weighted setup is arguably the DJIA’s biggest quirk. A company worth $50 billion with a $50 share price carries less weight in the index than a company worth $20 billion with a $200 share price. Market cap, the actual size of the company, doesn’t factor in directly at all.

Who Decides Which Companies Are in the Dow?

There’s no strict formula for getting into the Dow, which surprises a lot of people used to indexes with clear numeric cutoffs.

According to S&P Dow Jones Indices, a company is typically added only if it has a strong reputation, shows sustained growth, and draws interest from a large number of investors. Stock price matters too, since the index is price-weighted, and the committee also tries to keep a reasonable balance across sectors so the Dow doesn’t end up overloaded with, say, banks or tech firms.

In practice, a small committee reviews the index periodically and swaps companies in or out when one no longer represents its industry well or when a merger, bankruptcy, or major shift makes a change necessary. There’s no public vote and no set schedule. It happens when it needs to.

Dow vs. S&P 500 vs. Nasdaq Composite

These three indexes get mentioned together constantly, but they’re measuring different things.

Feature	Dow Jones (DJIA)	S&P 500	Nasdaq Composite
Number of companies	30	500	Over 2,500
Weighting method	Stock price	Market capitalization	Market capitalization
Founded	1896	1957 (current form)	1971
Typical focus	Large, established blue chips	Broad U.S. economy	Heavy tech representation

The S&P 500 is generally seen as the better gauge of the overall U.S. market simply because it covers so many more companies across every major sector. The Nasdaq Composite skews toward technology since most of its listings trade on the Nasdaq exchange. The Dow, meanwhile, trades breadth for name recognition. It only tracks 30 companies, but they’re companies almost everyone has heard of.

Why the Dow Still Matters to Everyday Investors

You can’t invest directly in the DJIA the way you’d buy a stock, but its movements still affect your portfolio and your read on the market in a few practical ways.

It’s a quick pulse check. Because the Dow only has 30 components, it’s easy to glance at and get a rough sense of how large-cap American business is doing that day.

It influences related funds. Exchange-traded funds like the SPDR Dow Jones Industrial Average ETF track the index directly, letting investors gain exposure to all 30 companies through a single fund.

It shapes market sentiment. Even though professional investors often lean on the S&P 500 for a fuller picture, the Dow’s headline number still moves public perception. A 500-point drop makes news whether or not it reflects the broader market accurately.

It highlights blue-chip stability. The companies in the Dow tend to be less volatile than smaller, newer firms, which makes the index a reasonable, if imperfect, proxy for how conservative, established businesses are performing.

The Dow’s Limitations and Criticisms

No index is perfect, and the Dow draws more criticism than most for a few specific reasons.

Its biggest weakness is the price-weighting system itself. A company’s stock price often has nothing to do with its actual size or importance. A firm can have a $50 stock price and a trillion-dollar valuation, while a much smaller company trades at $400 a share and pushes the index around more. That’s backwards from how most people intuitively think about company influence.

The Dow also only tracks 30 companies. Compare that to the S&P 500’s 500 or the Nasdaq’s thousands, and it’s easy to see why some analysts consider the Dow too narrow to represent the whole U.S. economy. A single company having a rough quarter can swing the entire index in a way that wouldn’t register on a broader benchmark.

None of this makes the Dow useless. It’s simply narrower and quirkier than its reputation suggests, and it’s worth reading alongside the S&P 500, not instead of it, if you want a fuller picture of market health.