A fund whose strategy is to invest in other PE funds rather than directly in portfolio companies, providing smaller LPs with diversified PE access (across vintages, strategies, geographies) without the resources to build a direct primary program. Trade-off: fee-on-fee drag — the fund-of-funds layer adds 50-100 bps of management fee plus 5-10% carry on top of underlying-fund economics, typically resulting in 200-300 bps lower net IRR than direct primary access. Fund-of-funds interests trade at 15-25% discount to NAV in the secondary market reflecting this fee drag.