Westfield (Mass.) State College Foundation is terminating Commonfund, which ran the foundations $5 million in assets, because of disagreements over an appropriate benchmark for Commonfunds multistrategy equity fund. The foundation is moving the bulk of its $5 million in assets into Vanguard index funds, said Sheridan Carey, chairman of the foundations investment committee. In a telephone interview, Mr. Carey said Commonfund switched the benchmark for its equity offering which gives smaller endowments and foundations access to the kind of diversified portfolios top universities have crafted to the S&P 500 a few years ago, from a customized benchmark that better reflected the multistrategy funds investments in other asset classes, including international equities, emerging markets stocks and hedge funds. While performance remained good, that change made it difficult to gauge whether Commonfund is adding value, Mr. Carey said. John S. Griswold, executive director of the Commonfund Institute, which oversees Commonfunds education and research activities, said as a matter of policy Commonfund doesnt comment on client affairs.