How Much Should You Invest in Private Markets?

There is no universal percentage for private-market allocation, and the question is best answered backwards: start from loss capacity, not from a target return. Ask what maximum private-market loss the household could absorb without changing its plans for a home, education or retirement, and size the allocation to that number, not to a fund's minimum ticket or a relationship manager's suggested figure.

Build the calculation on investable financial assets, not headline net worth that includes illiquid property or a business stake. Separate liquid reserves, capital already committed but not yet called, current private holdings, and future planned commitments by vintage year — each should carry an explicit job (income, capital preservation, growth, or high-variance upside), not sit as one undifferentiated 'alternatives' bucket.

The most common and costly mistake is counting only cash already drawn down as the 'private markets' exposure. That understates true illiquidity substantially, and it can leave an investor dependent on an unplanned asset sale, an annual bonus, or fresh borrowing exactly when several fund managers issue capital calls in the same period — a genuinely common occurrence when several commitments share a similar vintage.

Before committing, write down in one place: the specific role this exposure plays in the portfolio, the maximum capital genuinely at risk including unfunded commitments, the realistic expected holding period including likely extensions, the source of funds for future capital calls, and the conditions under which the entire plan would need to be revisited.

The right allocation size is one that survives delayed distributions, capital calls arriving earlier than expected, and a two-year fund extension — all at once — without disturbing the family's core financial plan.