Memory storing terms of a contract for reducing accounting volatility and risk, the terms including specification of at least one measure of variation in a rate of return corresponding to a return on an investment portfolio, a variable speed of adjustment factor and a contract rate of return on an investment associated with the investment portfolio, wherein the amount of the measure of the variation changes over time; a computer computing an amount for the at least one measure of variation, calculating an amount for the adjustment speed factor and using the amounts in: determining at least one of a contract rate of return on the investment associated with the investment portfolio and a contract value for the investment associated with the investment portfolio to produce output.