Under normal circumstances, at least 80% of the fund's net assets will be invested in mid cap equity securities. The fund's portfolio managers consider mid-capitalization companies to be those companies that, at the time of initial purchase, have market capitalizations greater than $1 billion and equal to or less than the largest company in the Russell Midcap® Index during the most recent 12-month period. It maintains a portfolio of investments diversified across companies and economic sectors.