What Is Public Market Equivalent (PME)?
PME answers a deceptively simple question: if a limited partner had invested every capital call in a public index like the S&P 500 and sold shares whenever the fund made a distribution, would the LP have ended up richer or poorer than it did in the fund? By mirroring the exact timing and size of the fund's cash flows, PME creates an apples-to-apples comparison that raw return figures cannot.
The measure exists because IRR and MOIC, the standard private equity metrics, say nothing about opportunity cost. A fund posting a 15 percent IRR looks strong in isolation, but if public equities returned 18 percent over the same window, the LP paid fees and accepted illiquidity for underperformance.
How PME Is Calculated
The most widely used version is the Kaplan-Schoar PME. Each contribution and distribution is grown forward at the index's return to a common date, and the ratio is computed as the future value of all distributions plus the fund's remaining net asset value, divided by the future value of all contributions. A result of 1.10 means the fund delivered about 10 percent more wealth than the index strategy.
Earlier variants include the Long-Nickels index comparison method, which builds a hypothetical index portfolio and compares IRRs, along with refinements like PME+ and Direct Alpha that fix distortions when funds distribute heavily. Whichever version is used, the choice of benchmark index materially changes the answer, so LPs match the index to the fund's strategy.
Why PME Matters
PME has become the academic and institutional standard for judging whether private equity actually earns its fees. Landmark studies by Kaplan and coauthors found that US buyout funds historically posted PMEs modestly above 1.0 versus the S&P 500, an edge that narrows or disappears in some periods and benchmark choices, which fuels the ongoing debate over the asset class.
The metric also guards against games that flatter IRR, such as subscription credit lines that delay capital calls and inflate early returns. For anyone interviewing with a fund of funds, an LP, or a secondaries investor, being able to explain what a PME of 1.2 means and why it can diverge from a high IRR signals real fluency in performance measurement.
