Hornbeck Offshore Services (NYSE: HOS) provides technologically advanced offshore supply vessels, primarily in the U.S. Gulf of Mexico and select international markets. It is also a leading transporter of petroleum products, through a fleet of ocean-going tugs and tank barges in the northeastern U.S., the U.S. Gulf of Mexico and Puerto Rico. The company's fleet of over eighty vessels primarily serves the energy industry. Clients include Anadarko Petroleum (NYSE: APC), Chevron (NYSE: CVX) and ConocoPhillips (NYSE: COP).

Hornbeck pleased investors earlier in the month, when it reported Q3 EPS of $1.09 and revenues of $94.7 million. Analysts had been expecting 83 cents and $88.9 million. Management also guided FY07 EPS to $3.28-$3.52, versus consensus of $3.17. HOS shares popped on the news and then moved into a bullish "flag" consolidation pattern Prices frequently exit flags moving in the same direction they were traveling when they entered them. In this case, that would be to the upside.

The S&P 500 has announced several changes to the index. Ensco International (NYSE:ESV) is replacing BellSouth (NYSE:BLS). Cimarex (NYSE:XEC) will join the S&P Midcap 400. Hornbeck Offshore Services (NYSE:HOS) will join the Small Cap 600.

As the stocks are added to major indices, many index funds will be forced to buy them to stay current with the indices they track. Other "closet index funds" may add them as well. Should you?

If history is any guide, probably not. According to a piece in last week's Wall Street Journal [subscription required]: "... buy stocks that have been removed from the S&P 500. Those that suffered that indignity this year are up 27% on average since removal, while those that were added to the index are up only 1% since joining, notes Paul Hickey of Birinyi Associates."

While there were no stocks demoted in this group (BellSouth is no longer listed as it was acquired by AT&T.), the data would seem to suggest that investors may do well to avoid ESV and possibly HOS and XEC too.