Dow Jones refers to two related things: a stock market index that acts as a quick snapshot of the U.S. economy, and a media and financial data company that publishes The Wall Street Journal. Most people asking “what does Dow Jones do” are hearing about the Dow Jones Industrial Average (DJIA) in the news and want to understand what it actually measures and why it matters. Here’s how both sides work.
The Index: A 30-Stock Economic Snapshot
The Dow Jones Industrial Average tracks the stock prices of 30 large, well-established American companies. Created in 1896, it was designed to serve as a proxy for the health of the broader U.S. economy. When a news anchor says “the Dow is up 200 points today,” they’re reporting the combined price movement of those 30 stocks.
The companies in the DJIA span nearly every major sector of the economy, with the notable exceptions of utilities and transportation (which have their own separate Dow Jones indexes). The 30 stocks are all blue-chip companies, meaning they’re large, financially stable, and widely recognized. Think names like Apple, Goldman Sachs, and Coca-Cola. Investors and analysts use the Dow to gauge broad market trends and overall economic confidence. A rising Dow generally signals optimism about the economy; a falling Dow suggests worry.
How the 30 Companies Are Chosen
There’s no strict formula for getting into the DJIA. The 30 components are selected by the editors of The Wall Street Journal, who periodically swap companies in and out to keep the index reflective of the current economy. A company that dominated American industry 20 years ago might be replaced by one that better represents where the economy is headed today. This process is more subjective than the selection criteria for broader indexes like the S&P 500, which has specific financial requirements a company must meet.
How the DJIA Is Calculated
The DJIA is a price-weighted index, which makes it different from most other major indexes. In a price-weighted index, stocks with higher share prices have more influence on the index’s movement, regardless of the company’s total market value. If a stock trading at $300 per share drops by $10, that moves the Dow more than a $10 drop in a stock trading at $50.
The actual calculation works like this: add up the share prices of all 30 companies, then divide by a special number called the Dow Divisor. The divisor is not 30. It’s a much smaller figure (recently around 0.16) that gets adjusted whenever a component stock splits, pays a special dividend, or gets swapped out for a new company. These adjustments keep the index level consistent over time so that a stock split doesn’t suddenly cause the Dow to plunge even though nothing economically changed.
Because the divisor is less than one, it actually functions as a multiplier. At recent divisor levels, every $1 change in any single component stock’s price translates to roughly a 6-point move in the index. That’s why a handful of high-priced stocks can swing the Dow by hundreds of points on a volatile day.
The Company Behind the Name
Dow Jones is also a media and financial information company. It started as a small news agency in a Wall Street basement and has grown into a collection of well-known brands. Its flagship publication is The Wall Street Journal, one of the most widely read business newspapers in the world. Dow Jones also owns Barron’s (an investment-focused magazine), MarketWatch (a financial news website), Investor’s Business Daily, Dow Jones Newswires, and Factiva (a business research database). On the compliance side, it operates Dow Jones Risk & Compliance, which helps companies screen for financial crime risks.
Dow Jones itself is owned by News Corp. The company’s index business, including the DJIA, is managed through S&P Dow Jones Indices, a joint venture with S&P Global.
Why the Dow Still Matters
Critics point out that 30 stocks is a tiny slice of the market. The S&P 500 tracks 500 companies and uses market-cap weighting, which many professionals consider a more accurate reflection of overall market performance. The Dow’s price-weighting quirk means a company with a high share price can dominate the index even if it’s not the largest company by total value.
Still, the DJIA remains the most widely quoted stock index in everyday conversation. Television networks display it constantly, newspaper headlines reference it daily, and millions of people use it as their go-to gauge of whether the market had a good or bad day. Its longevity and simplicity give it staying power. When someone says “the market was up today,” they’re often talking about the Dow, even if more comprehensive indexes tell a fuller story.
Can You Invest in the Dow?
You can’t buy the DJIA directly since it’s just a number, not a fund. But several exchange-traded funds (ETFs) and mutual funds are designed to mirror its performance by holding the same 30 stocks in the same proportions. The most popular is the SPDR Dow Jones Industrial Average ETF (ticker: DIA). Buying shares of a Dow-tracking fund gives you exposure to all 30 components in a single investment, which offers diversification across major sectors without needing to purchase each stock individually.