Under normal circumstances, the fund invests at least 80% of its net assets (plus any borrowings for investment purposes) in securities included in the underlying index. The index is composed of common stocks of large companies that operate their businesses in a manner consistent with the calvert principles for Responsible Investment and are selected from the universe of the 1,000 largest publicly traded U.S. companies based on market capitalization, excluding business development companies. The fund is non-diversified.