The restricted stock method purports that the only difference between a company's common stock and its restricted stock is the lack of marketability of the restricted stock.
Subsequently, the price difference between both units should arise due to this lack of marketability. The IPO method relates to the price difference between shares that are sold pre-IPO and post-IPO. The percent difference between the two prices is considered the DLOM using this method. The option pricing method uses the option's price and the strike price of the option as the determinants of the DLOM. The option price as a percentage of the strike price is considered the DLOM under this method.
The consensus of many studies suggests that the DLOM ranges between 30-50%.