A computer system implementing at least one investment. A computer has a processor, connected to a memory device, to an input device, and to an output device, the processor programmed to control steps including: forming a synthetic investment fund by entering, as some of the input information, at least one of the group consisting of an amount of an interest-bearing asset, and an amount of a derivative instrument, and entering a specification of a relationship for the amounts; entering, as some of the input information, respective market prices for the interest-bearing asset and for the derivative instrument; calculating a unit value for each said class of interests in the fund in response to the market prices; and generating output for investor reporting, the output including holding data for each said class of interests in the fund and the unit value for each said class of interests in the fund.