Dow Jones & Company, which is listed on the New York Stock Exchange under the ticker symbol DJ, was founded in New York City in 1882 by Edward Davis Jones, Charles Henry Dow and Charles Milford Bergstresser.

The cornerstone of Dow Jones is its flagship publication, The Wall Street Journal, which also happens to be the world's leading business publication. The Journal, which was founded in 1889, has a current circulation of nearly 2.1 million.

The Dow Jones Industrial Average is an index of 30 "blue-chip" U.S. stocks. At 100-plus years, it is the oldest continuing U.S. market index. It is called an "average" because it originally was computed by adding up stock prices and dividing by the number of stocks. (The very first average price of industrial stocks, on May 26, 1896, was 40.94.) The methodology remains the same today, but the divisor has been changed to preserve historical continuity. The DJIA is the best-known market indicator in the world, partly because it is old enough that many generations of investors have become accustomed to quoting it, and partly because the U.S. stock market is the globe's biggest.

The industrial average started out with 12 in 1896, rising to 20 in 1916. The 30-stock average made its debut in 1928, and the number has remained constant ever since.

Microsoft and Intel are the only blue-chips that are not quoted on the New York Stock Exchange (NYSE). They are laisted on Nasdaq.

How are stocks picked for the DJIA?

The editors of The Wall Street Journal select the components of the industrial average. They take a broad view of what industrial means, too; in essence, it is almost any company that isn't in the transportation business or isn't a utility (because there also are Dow Jones Averages for those kinds of stocks). In choosing a new company for the DJIA, they look among substantial industrial companies with a history of successful growth and wide interest among investors. The components of the DJIA are not changed often. It isn't a "hot stock" index, after all, and the Journal editors believe that stability of composition enhances the trust that many people have in the averages. The most frequent reason for changing a stock is that something is happening to one of the components, such as being acquired. Whenever one stock is changed, the rest are reviewed.

What happened to the original 12 companies in the DJIA?

There are two ways to measure: index points and percentage change. Here are tables of the biggest one-day rises in both terms.