Last Modified: October 2, 2026
Table of Contents
The Dow Jones Industrial Average is a price-weighted stock market index tracking thirty large, publicly traded United States companies selected by a committee at S&P Dow Jones Indices as representative of the breadth and diversity of the American economy, serving as the oldest continuously published stock market benchmark in the United States and the most widely quoted single indicator of stock market performance in global financial media. Created on May 26, 1896 by Charles Dow — co-founder of Dow Jones and Company and editor of The Wall Street Journal — and his business associate Edward Jones, it is the foundational reference point against which every securities professional and investor measures the performance of the domestic equity market.
Charles Dow first published a market average on July 3, 1884 — the Dow Jones Transportation Average, then called the Dow Jones Railroad Average, tracking eleven companies of which nine were railroads. The Dow Jones Industrial Average followed on May 26, 1896 as a separate average covering twelve companies engaged in the industrial sectors that dominated the American economy in the late nineteenth century: cotton, sugar, tobacco, lead, leather, rubber, and basic manufacturing. The original twelve components bore no resemblance to the index as it exists today — only General Electric appeared in both the original 1896 index and the modern composition, and even GE was ultimately removed in June 2018, ending its more than century-long association with the average.
The index expanded to twenty companies in 1916 to broaden its coverage as the economy diversified beyond the original industrial categories, then expanded again to thirty companies in 1928 — the number at which it has remained ever since. The selection of thirty was a deliberate choice reflecting the practical limits of manual calculation at the time and the desire to maintain a manageable, comprehensible index rather than an unwieldy average of hundreds of companies.
The Dow Divisor — the mathematical factor that converts the sum of component stock prices into the index level — was originally set equal to the number of component companies, making the early index a simple arithmetic average. As stock splits, company substitutions, and other corporate actions accumulated over the following century, the divisor was adjusted repeatedly to maintain index continuity. Today the divisor is a small fraction rather than a whole number, meaning the index level is substantially higher than the sum of the thirty component stock prices. The precise current value of the divisor is published daily by S&P Dow Jones Indices and is available on their website.
The Dow Jones Industrial Average is a price-weighted index — the single most important methodological characteristic that distinguishes it from every other major United States equity benchmark and that has significant implications for which companies exercise the greatest influence over daily index movements.
In a price-weighted index, each component's contribution to the index level is proportional to its share price rather than to its total market capitalisation. A company with a share price of three hundred dollars moves the Dow three times as much per percentage point of price change as a company with a share price of one hundred dollars, even if the one-hundred-dollar company has a substantially larger total market capitalisation because it has more shares outstanding.
The calculation is straightforward: the sum of the thirty component stock prices is divided by the Dow Divisor to produce the index level. A one-dollar increase in any component stock price moves the index by exactly the same number of points regardless of which stock experienced the change. Because every dollar change in every stock has an identical point impact on the index, the highest-priced stocks exert the greatest influence on index movements in proportional terms.
This price-weighting methodology has been extensively criticised by financial economists and investment professionals as an arbitrary and economically unjustified basis for index construction. A company's share price is a function of both its economic scale and its decision about how many total shares to have outstanding — a company that has never split its stock will have a much higher price per share than an economically larger company that has split its stock multiple times, and the Dow will weight them as if price-per-share were a meaningful measure of importance in the economy. The S&P 500, the Russell indices, and virtually every other modern stock market benchmark use market capitalisation weighting rather than price weighting specifically because market capitalisation — price multiplied by shares outstanding — reflects the actual economic scale of each company and its proportionate importance in the economy.
Despite this criticism, the Dow's longevity and its extraordinary degree of public recognition make it a permanent fixture in financial market discourse. Its daily closing level is broadcast on every major news network, cited in every financial publication, and referenced by policymakers and politicians as a shorthand for the condition of the American economy. No other equity benchmark approaches the Dow's cultural visibility.
The thirty companies comprising the Dow Jones Industrial Average are selected by a committee at S&P Dow Jones Indices, the entity majority owned by S&P Global that maintains the index under a licensing agreement with News Corp's Dow Jones and Company, which retains the brand. The Wall Street Journal editorial board historically played a role in component selection decisions, though the formal authority resides with the S&P Dow Jones Indices committee.
S&P Dow Jones Indices publishes formal methodology criteria for Dow component selection. A company must be incorporated in the United States, listed on a United States exchange, have an excellent reputation, demonstrate sustained growth, and be of significant interest to a large number of investors. The index intentionally excludes companies from the transportation and utilities sectors — which are tracked by the Dow Jones Transportation Average and the Dow Jones Utility Average respectively — but otherwise covers all major sectors of the economy. S&P Dow Jones Indices states explicitly that the definition of industrial is kept intentionally broad to provide an indicator that reflects the performance of the entire United States economy rather than any narrow segment.
Component changes occur infrequently and are significant market events when they do occur. A company added to the Dow receives a meaningful stamp of institutional validation — an acknowledgment by the index committee that it has achieved the scale, stability, and representativeness required for membership in the most prestigious equity benchmark. A company removed from the Dow — as General Electric was in June 2018 — typically signals that the index committee has concluded the company no longer represents the economy's most important sectors or has experienced sufficient deterioration that continued inclusion would misrepresent the index's purpose.
More than fifty companies have been members of the Dow Jones Industrial Average at some point since its creation. Recent additions including Salesforce, Amazon, and Amgen reflect the shift in the American economy from heavy manufacturing toward technology, healthcare, and services. The current thirty-component roster represents the committee's ongoing effort to keep the index relevant as the economy evolves, even within the constraints of a fixed thirty-company count.
The distinction between the Dow Jones Industrial Average and the S&P 500 is among the most examination-relevant comparisons in the securities industry curriculum and reflects a genuine difference in the information each index provides.
The S&P 500, maintained by S&P Dow Jones Indices since its creation in 1957, tracks five hundred large-capitalisation United States companies weighted by their float-adjusted market capitalisation — the market value of shares available for public trading rather than the total shares outstanding including closely held insider shares. Because it covers five hundred companies weighted by economic scale, the S&P 500 is a far more statistically representative sample of the broad United States equity market than the Dow's thirty price-weighted components. Most academic research on United States equity market returns uses the S&P 500 as the benchmark, and most institutional investors measure their performance against it.
The Dow's advantage over the S&P 500 is simplicity and longevity. Its one-hundred-and-twenty-nine-year continuous history provides a far longer data series than any other American equity benchmark, allowing historical comparisons across business cycles, wars, depressions, technological revolutions, and monetary regimes that no other index can provide. Its thirty blue-chip components are household names familiar to non-specialist audiences in a way that the broader S&P 500 universe is not.
And despite the methodological criticisms, the correlation between daily Dow movements and daily S&P 500 movements is very high — the two indices tend to move in the same direction and in roughly similar magnitudes because both are heavily influenced by the largest and most important American companies, many of which are members of both indices.
The Dow Jones Composite Average, published by Dow Jones since 1934, combines all sixty-five companies in the three Dow averages — thirty industrials, twenty transportation, and fifteen utilities — into a single broader benchmark. It is rarely referenced in practice but illustrates the original family of Dow averages.
Securities professionals and examination candidates must understand precisely what a point movement in the Dow Jones Industrial Average means and how it relates to a percentage change.
One point in the Dow equals one dollar of combined price change across the thirty components divided by the Dow Divisor. Because the divisor is currently a small fraction, one dollar of total price change in all thirty components — or equivalently, one dollar of price change in a single component — produces an index movement of several points. A one-dollar increase in a stock trading at twenty dollars represents a five percent gain in that stock. A one-dollar increase in a stock trading at four hundred dollars represents a zero point two five percent gain. The Dow treats these identically in terms of point impact even though their economic significance is vastly different. Percentage moves in any component must be converted to dollar moves to assess their actual impact on the Dow's point level.
A one-percent move in the Dow Jones Industrial Average, expressed in percentage terms, represents the same percentage change regardless of the absolute index level. When the Dow stands at thirty thousand, a one-percent move equals three hundred points. When it stood at one thousand, a one-percent move equalled ten points. Percentage moves are therefore always the more meaningful expression of market movement than raw point changes, and candidates should be comfortable converting between the two.
The Dow Divisor is adjusted by the index committee every time a component company takes a corporate action that would otherwise distort the index level — most commonly a stock split, a reverse stock split, or a change in component membership.
When a component stock splits two-for-one, its price per share falls by approximately half while the shareholder's economic position is unchanged — they hold twice as many shares at half the price. Without an adjustment to the Dow Divisor, this mechanical price reduction would appear as a drop in the Dow index level, falsely suggesting a market decline when none has occurred. The index committee adjusts the divisor downward in response to a split so that the index level is unchanged immediately after the split takes effect, preserving continuity.
Similarly, when one company is added to the index and another removed, the prices of the incoming and outgoing stocks differ, and the composition change would otherwise create an artificial discontinuity in the index level. The divisor is adjusted on the day of the substitution so that the index opens at the same level it would have reached if no change had occurred, maintaining the integrity of the historical series.
Because the divisor has been adjusted hundreds of times since 1896 through splits, substitutions, and other corporate actions, it has fallen far below its original value of thirty. The current divisor is a fraction considerably less than one, which means the index level is substantially larger than the sum of the thirty component prices. This is purely a mathematical consequence of the accumulated divisor adjustments and has no economic significance.
Despite its methodological limitations, the Dow Jones Industrial Average exercises a genuine influence on investor psychology and market sentiment that no financial professional can ignore. News coverage of market movements almost universally leads with the Dow's performance rather than the S&P 500 or any broader benchmark, because the Dow's simplicity and brand recognition make it the default reference for non-specialist audiences.
This media prominence means that extreme Dow moves — particularly round-number milestones and large point declines — generate disproportionate public attention relative to their actual market significance. The Dow crossing ten thousand for the first time in March 1999 generated extensive coverage even though the S&P 500 provided a more meaningful picture of market conditions. The Dow's largest single-day point declines during the 2020 COVID-19 pandemic — including a two-thousand-nine-hundred-and-ninety-seven-point decline on March 16, 2020, the largest point drop in the index's history at the time — generated enormous public alarm, though the percentage decline that day of approximately thirteen percent, while severe, was not the largest in the index's history.
The Dow Jones Transportation Average, which predates the Industrial Average, tracks twenty transportation companies — airlines, railroads, and trucking firms — and is particularly associated with Dow Theory, the technical analysis framework developed from Charles Dow's writings. Dow Theory holds that a sustained move in the Industrial Average must be confirmed by a concurrent move in the Transportation Average to signal a genuine trend change, based on the economic logic that rising industrial production requires corresponding increases in the transportation of goods. Dow Theory confirmation patterns appear in technical analysis curricula and are referenced in securities examination contexts.
The Dow Jones Industrial Average is tested on the SIE, Series 7, and Series 65 examinations in the context of market indices, index construction methodology, blue chip equities, market benchmarks, and technical analysis.
The core points to retain are these: the Dow Jones Industrial Average was created on May 26, 1896 by Charles Dow and Edward Jones, initially tracking twelve companies and expanded to thirty in 1928, making it the oldest continuously published United States stock market benchmark.
It is a price-weighted index — the sum of the thirty component stock prices is divided by the Dow Divisor to produce the index level, meaning higher-priced stocks exert greater influence on index movements than lower-priced stocks regardless of their total market capitalisation; this price-weighting methodology distinguishes the Dow from the S&P 500 and virtually all other modern benchmarks, which use market capitalisation weighting to reflect each company's proportionate economic scale.
The Dow Divisor is adjusted whenever a component stock splits, a component is added or removed, or other corporate actions would otherwise create artificial index discontinuities, and it is now a fraction less than one because of accumulated adjustments over more than a century; the thirty components are selected by a committee at S&P Dow Jones Indices — which is majority owned by S&P Global — based on criteria including United States incorporation, exchange listing, excellent reputation, sustained growth, and investor interest, with transportation and utilities companies excluded because they are covered by separate Dow Jones averages; membership changes are infrequent and significant, with recent additions including Salesforce, Amazon, and Amgen reflecting the economy's shift toward technology and healthcare from its original industrial composition; the S&P 500 is a superior statistical benchmark for the broad United States equity market because it covers five hundred companies weighted by market capitalisation, but the Dow's one-hundred-and-twenty-nine-year continuous history and extraordinary public recognition make it the most widely cited equity market indicator; one percentage point of price change in a higher-priced component moves the Dow more points than the same percentage change in a lower-priced component, making percentage changes the more meaningful expression of index movement than absolute point changes; and Dow Theory, derived from Charles Dow's writings, holds that sustained Industrial Average moves must be confirmed by concurrent Transportation Average moves to signal genuine trend changes.
