Dow 101: The Dow and why it matters

BEGINNINGS

Charles H. Dow created the index with the intention of giving the stock market credibility and making investing more understandable. The original Dow Jones industrial average had 12 members and was published May 26, 1896. It featured companies such as American Cotton Oil, Chicago Gas and U.S. Rubber.

A SELECT GROUP

The number of companies making up the index increased gradually and then expanded from 20 to 30 in October 1928. Entry into the index is reserved for a company that "has an excellent reputation, demonstrates sustained growth and is of interest to a large number of investors."

LONGEST-STANDING MEMBER

General Electric Co. is the only original member in the Dow. The industrial giant was briefly delisted but has stayed in the index since its reinstatement in 1907.

BEST AND WORST

The Dow's biggest point jump was on Oct. 13, 2008, when the average rose 936.42 points, or 11 percent, to close at 9,387.61. The surge followed the announcement of a European plan to bail out financial institutions. Its biggest percentage jump was more than 15 percent on March 15, 1933, after the stock market reopened. The government essentially agreed to insure banks' deposits while the market was closed.

The Dow's biggest point drop was 777.68 points, or 7 percent, on Sept. 29, 2008. That was the day Congress rejected a plan by the George W. Bush administration to bail out the financial industry. The Dow's biggest percentage drop was on Oct. 19, 1987, when the index fell 508 points, or almost 23 percent, to close at 1,738.74. Among the causes of that crash were rising interest rates, the U.S. bombing of Iranian oil platforms and a sudden loss of investor confidence.