A portfolio manager is a person or group of people responsible for investing a mutual, exchange traded or closed-end fund's assets, implementing its investment strategy, and managing day-to-day portfolio trading. A portfolio manager is one of the most important factors to consider when looking at fund investing. As an investment and portfolio manager, your primary task will be to understand the financial conditions and goals of individual clients or businesses and make investment decisions on behalf of them or advise them where to invest in regards to shares, bonds, mutual funds, etc.