On behalf of an arbitration respondent, Cornerstone Research evaluated the impact of a disputed appraisal on the value of a ground lease. We investigated alternative valuation methods, collected comparable real estate market data, and analyzed expected future cash flows. Using market data on real estate price volatility, Cornerstone Research applied financial option theory to value a rent floor provision in the ground lease. We were able to establish that the rent floor provision had a much smaller impact on the present value of future cash flows than asserted by the complainant, reducing claimed damages by more than 60 percent.