“The reason for having a longer roll period is simply to ensure a very low tracking error going forward, since traders had to roll large quantities of contracts in a single day before,” said Steve Harris, senior product manager for analytics at Thomson Reuters.

Orange juice was replaced due to its relatively lower liquidity to soy oil and position limits that are more restrictive, according to the article.

“The arithmetic model more accurately reflects investor returns and better serves ETFs that track commodity indexes,” Harris added.

GCC, the ETF tied to the index, won the 2012 Morningstar ETF Award for best commodities broad basket fund in the retail category.

“For an unusual and successful approach to broad-basket commodities investing, GreenHaven Continuous Commodity Index is worth a look,” Morningstar analyst Abby Woodham wrote in a profile of the ETF. “Most of its peers weight their portfolios by economic significance, which results in an energy overweighting. GCC allocates equally to all 17 commodities it tracks, which has historically resulted in strong relative performance and lower volatility.”