UnitedHealth Group Inc. has landed a spot in the Dow Jones industrial average, the elite group of 30 companies that many investors look to as a gauge of the stock market.

S&P Dow Jones Indices said Friday that the Minnetonka-based company, which operates the nation's largest health insurer, will replace Kraft Foods Inc. at the opening of trading on Sept. 24. UnitedHealth joins 3M as Minnesota's only Dow stocks.

UnitedHealth's inclusion reflects its growth into the largest publicly traded company in Minnesota, with revenue that eclipsed $100 billion for the first time last year. The company's addition to the Dow list is also a sign of the growing influence of health care on the broader economy. "It is the largest, most successful and most well-respected health care company in the United States," Thrivent Financial analyst David Heupel said. "You can't sugarcoat or play it down. This is a select group."

The Dow, more than a century old, is considered an important reflection of the U.S. economy. Because the stocks are widely held by investors, the Dow remains one of the most tracked indexes in the world and provides a window into where the market is heading.

But in practical terms, analysts say, the Dow is not as representative as the broader Standard & Poor's 500. It includes a relatively small selection of very large companies, and its "blue chip" selections don't include transportation or utility companies.

UnitedHealth Group will join Johnson & Johnson, Merck and Pfizer as the only Dow stocks in the health care arena. Travelers, which was added in 2009 when General Motors and Citigroup were replaced, is the only other insurance company.

"This helps broaden the diversity of the index, which is a positive," Heupel said. "This isn't another me-too pharma company. Its influences are somewhat different that other parts of the Dow."

A storied history

Charles H. Dow, one of the founders of Wall Street Journal publisher Dow Jones & Co., formed the Dow average on May 26, 1896, to represent the dollar average of 12 stocks from America's top industries.

Original members included energy companies such as General Electric (the only original company still listed) and major players in coal and gas, as well as agricultural and manufacturing companies dealing in cotton, sugar, tobacco and rubber.

The Dow average was expanded to 20 companies in 1916 and reached its present mark of 30 in 1928, reflecting the boom-time growth of the Roaring Twenties.

Despite its name, the Dow no longer is filled with titans of the industrial era. It now includes such names as Microsoft, Coca-Cola, Bank of America and McDonald's. The list has changed 48 times in its history.

The committee that selects stocks for inclusion focuses on the kind of company that has an "excellent reputation, demonstrates sustained growth and is of interest to a large number of investors," according to S&P Dow Jones Indices.

Kraft Foods, the nation's second-largest food company, joined the list in September 2008. It plans to spin off its North American grocery business, making it too small for inclusion.

UnitedHealth shares enjoyed a brief lift in the morning after the news before dipping for the remainder of the trading day. The stock finished up 36 cents, less than 1 percent, at $54.25.

Jackie Crosby • 612-673-7335