The fund invests at least 80% of assets in securities of companies principally engaged in the energy service field, including those that provide services and equipment to the conventional areas of oil, gas, electricity, and coal, and newer sources of energy such as nuclear, geothermal, oil shale, and solar power. It invests in domestic and foreign issuers. The fund invests primarily in common stocks. It uses fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions to select investments. The fund is non-diversified.