The income that supports the activities of the National Academy of Sciences (NAS) comes from two major sources: program revenue received from sponsors to pay for the myriad studies and other activities undertaken each year by the National Research Council (NRC), and a much smaller sum that is obtained from our endowment under the endowment spending policies adopted by the Council. The goal of the endowment is to provide stable support for the Academy's programs and activities. To achieve this goal, the Council, acting on the recommendations of the Finance Committee, has historically authorized spending from the portfolio at a rate designed to maintain the purchasing power of the endowment over time.