Under normal circumstances, the fund will invest at least 80% of its assets in common stocks of mid-cap U.S. companies. A mid-cap company is defined as a company, at the time of purchase, which has a market capitalization between $1.5 billion and $12 billion or falls within the range of market capitalizations represented in the Russell Midcap® Index. The size of the companies in the Russell Midcap® Index will change with market conditions.