Original: Most funds are overseen by a board of directors or trustees ( if the U.S. fund is organized as a trust as they commonly are ) which is charged with ensuring the fund is managed appropriately by its investment adviser and other service organizations and vendors , all in the best interests of the fund 's investors .
Simplified: A fund manager ( or '' portfolio manager '' ) decides how to invest the money , and for this he is paid a fee , which comes from the money in the fund .