A method, machine, article for contract values. The method can include: storing in memory terms of an agreement governing a stable value contract whereby a stable value return is to be determined by using a built-up moving average of the yield-to-worst outcome of an investment portfolio; calculating, by a digital computer accessing the memory and receiving market data, an amount of the built-up moving average; determining, by the computer using the amount, at least one of a stable value return on the investment portfolio and a contract value for the investment portfolio; and outputting, by the computer, at least one of the determined stable value return and the determined contract value.