A method of operating a market for a plurality of participants to invest in a plurality of competitors using a computer system includes: storing a plurality of share holdings of the participants in the computer system; storing a plurality of credit balances of the participants in the computer system; and redeeming shares at the conclusion of a period in the computer system, wherein redeeming shares includes: calculating an amount that the credit balance of each corresponding participant of the participants should be modified in accordance with a plurality of values of corresponding ones of the shares at the conclusion of the period and the share holdings of the corresponding participant, and determining the values of the shares based on a benchmark ranking of the competitors at the conclusion of the period.