Private equity has traditionally been thought to provide diversification benefits. However, these benefits may be lower than anticipated as we find that private equity suffers from significant exposure to the same liquidity risk factor as public equity and other alternative asset classes. The unconditional liquidity risk premium is about 3% annually and, in a four‐factor model, the inclusion of this liquidity risk premium reduces alpha to zero. In addition, we provide evidence that the link between private equity returns and overall market liquidity occurs via a funding liquidity channel.

Twelve trillion dollars are allocated to private market funds that require outside investors to commit to transferring capital on demand. We show within a novel dynamic portfolio allocation model that ex‐ante commitment has large effects on investors' portfolios and welfare, and we quantify those effects. Investors are underallocated to private market funds and are willing to pay a larger premium to adjust the quantity committed than to eliminate other frictions, like timing uncertainty and limited tradability. Perhaps counterintuitively, commitment risk premiums increase with secondary market liquidity, and they do not disappear when investments are spread over many funds.

We introduce a methodology to estimate the historical time series of returns to investment in private equity funds. The approach requires only an unbalanced panel of cash contributions and distributions accruing to limited partners and is robust to sparse data. We decompose private equity returns from 1994 to 2015 into a component due to traded factors and a time‐varying private equity premium not spanned by publicly traded factors. We find cyclicality in private equity returns that differs according to fund type and is consistent with the conjecture that capital market segmentation contributes to private equity returns.