The fund invests primarily in U.S. common stocks. In selecting securities for the fund, the fund's investment adviser, Mairs & Power, Inc. (the Adviser), gives preference to companies that exhibit the potential for above-average growth and durable competitive advantages at reasonable valuations. The fund may also invest in securities of foreign issuers, which are listed on a U.S. stock exchange or are represented by American Depositary Receipts (ADRs).