Back in 2005: "Prosper: at the cutting edge of CPPI"

...The difference between traditional CPPI and Prosper is that rather than setting the cushion as the difference between the NAV of the investment and the PV of the cash component, it is set as the difference between the NAV and a prescribed guaranteed minimum value, which is a percentage of the highest ever NAV. As with traditional CPPI, if equity markets start to fall then equity exposure is reduced in favour of cash, but importantly, any earlier gains made are locked in.Furthermore,unlike traditional CPPI, Prosper can recover from a position of having little or no equity exposure. If all of the assets end up in cash then any interest earned will increase the cushion, which will then support increased equity exposure....