Private equity exits require explicit recognition of liquidity because marketability and transaction frictions materially change realizable value. The most robust practice combines a Discount for Lack of Marketability derived from restricted stock studies, an option-based DLOM that captures timing and lock-up effects, and liquidity-adjusted discount rates informed by market microstructure measures.
Measuring illiquidity for valuation
Restricted stock and pre-IPO studies remain a common empirical basis for DLOM because they reflect realized price differences when transferability is constrained. Aswath Damodaran New York University Stern School of Business has written extensively on marketability premiums and practical calibration methods. For dynamic timing effects, the Longstaff option model developed by Francis A. Longstaff UCLA Anderson School of Management treats the benefit of waiting to sell as analogous to an American option and yields higher discounts when exit windows are narrow or uncertain. These approaches explain causes of illiquidity such as limited buyer pools, contractual transfer restrictions, and information asymmetry that shorten the set of credible bidders at exit.
Market microstructure and risk-adjusted measures
When exits occur into public markets or through auctions, microstructure measures help quantify price impact and required compensation. The Amihud illiquidity measure attributed to Yakov Amihud New York University Stern School of Business links price moves to traded volume and is useful for calibrating temporary price impact in thin markets. The bid-ask spread and Roll implicit spread model introduced by Richard Roll University of California Berkeley provide observable proxies for execution cost. For discount-rate adjustments that reflect systematic liquidity risk across holding periods, the Acharya–Pedersen liquidity-adjusted CAPM by Viral V. Acharya New York University Stern School of Business and Lasse Heje Pedersen Copenhagen Business School integrates expected return premia for liquidity shortfalls.
Combining approaches produces the most defensible valuations because each measure captures different mechanics of illiquidity. Restricted stock studies and option models address marketability and timing, microstructure metrics capture transactional price impact, and liquidity-adjusted asset pricing captures systematic liquidity risk.
Practical consequences include improved exit pricing, fewer failed deals, and clearer alignment between LP expectations and GP incentives. In emerging markets and family-controlled firms, cultural norms and legal frameworks often amplify illiquidity so discounts should be larger and documented. For investments with environmental or territorial constraints such as infrastructure or land use projects, long lock-up horizons can justify heavier option-based adjustments. Valuation diligence that transparently combines these measures and cites authoritative standards reduces disputes and better reflects the economic realities of the exit process.