The Johnson/Park empirical method to estimate a discount for lack of marketability (DLOM) is one of the most popular methods business appraisers use for this purpose, according to a recent BVR survey. The method highlights the relation of the DLOM to the return on the investment and quantitatively measures the impact of the rate of return as a function of the DLOM. This methodology has been used in several tax court cases including the first family limited partnership (FLP) case to go to trial. The “2021 Discount for Lack of Marketability Study” provides objective rate-of-return measures to implement the Johnson/Park empirical method and includes a thorough explanation and example on how to apply these data.