The Fund normally invests at least 80% of its total assets in Office and Commercial Real Estate Companies, as defined below. The Index is comprised of equity securities of Office and Commercial Real Estate Companies and is intended to give investors a means of tracking the overall performance of U.S exchange-listed real estate investment trusts (REITs) involved in the office and commercial real estate markets. Office and Commercial Real Estate Companies are U.S. exchange-listed REITs that are primarily engaged in the office, industrial and/or retail real estate segments. Office and Commercial Real Estate Companies that derive at least 50% of their revenue from the office segment are considered office REITs and all others are considered commercial REITs. The Index is published by MarketVector Indexes GmbH (the Index provider), a wholly owned subsidiary of the Adviser.