The Dow Jones Index Oversight Committee announced today that General Motors (NYSE: GM) and Citigroup (NYSE: C) will be removed from the Dow Jones Industrial Average, effective June 8. Tech giant Cisco Systems (NASDAQ: CSCO) and the insurance-focused The Travelers Companies (NYSE: TRV) will take their places.

The move will boost the already-heavy technology weighting in the Dow, and will add an insurance company to take the place formerly held by AIG, which exited the index in September 2008.

For GM and Citigroup, the removal was predictable. GM's bankruptcy automatically disqualified the company from the index, and Citigroup has become essentially a government ward with an uncertain future ahead of it.

"We were reluctant to remove Citigroup at the height of the financial frenzy, but it is clear that the bank is in the midst of a substantial restructuring which will see the government with a large and ongoing stake," said Robert Thomson, editor-in-chief of Dow Jones, in a statement.

The selection of Cisco comes as little surprise. It has the third-largest market capitalization of any U.S. company not previously included in the Dow, trailing only Google and Apple. Its servers essentially run the Internet, which occupies a central place in the American economy.

Travelers, however, is a bit of an unusual choice, due to its relatively small size. With a market cap of $24 billion, it isn't even the largest insurer in America; that claim falls first to Berkshire Hathaway, and second to MetLife. It is the 78^th-largest component in the S&P 500, and will be the second-smallest company in the Dow (after Caterpillar, with a market cap of $22 billion).

While there is no requirement for the Dow to hold the largest companies in America, reaching this deep into the market capitalization spectrum is unusual. Many expected a larger financial services company, such as Wells Fargo, to enter the index instead. Clearly, however, the Dow Jones team felt that insurance was a necessary industry to represent in the index, and they chose Travelers to lock down the property and casualty segment of the industry.

This is not the first time Travelers has been in the index. The company entered the index in 1997, and was then acquired by Citigroup in 1999.

Recently, in fact, a number of companies have made round-trips to the index. AT&T was booted from the index in April 2004, only to re-enter in December 2005 after its merger with Dow component SBC Communications. Chevron was shoved from the index in 1999, only to return in February 2008.

The editorial team at Dow Jones suggested that another round-trip could be coming.

"We genuinely hope that once [Citigroup] has refashioned itself that we will again be able to consider it for inclusion," said Thomson. "Citigroup is a renowned institution, not only in this country, but around the world."