The optimizer says 25% private equity. The portfolio is $40 million. That $10 million PE allocation requires a seven-year lockup, and the client needs $1.2 million annually. The theoretically optimal allocation broke against reality in four places before you finished reading the investment policy statement (IPS).
Portfolio size determines which asset classes are accessible. A $5 billion pension can allocate 15% to PE ($750 million) across 8-10 funds. A $50 million family office allocating 15% has $7.5 million, enough for one or two fund commitments with minimal diversification within the asset class.
Small portfolios face minimum investment thresholds. Most institutional hedge funds require $1-5 million. Direct real estate needs hundreds of thousands per property. Timber and infrastructure may require $10 million+. Below these floors, you substitute public market proxies: REITs instead of direct real estate, listed infrastructure instead of infrastructure funds.
Large portfolios face market impact. A $100 billion SWF allocating 5% to small-cap equities deploys $5 billion into a segment where single positions must stay below 5% of a company's market cap.
Common mistakes
- Ignoring market impact for large portfolios. A $50 billion fund allocating 5% to small-cap equities faces implementation drag that erodes the expected return advantage. Candidates who recommend the allocation without discussing capacity lose marks.
- Assuming liquidity is constant across market conditions. Hedge fund redemption gates, PE distribution freezes, and widening bid-ask spreads all reduce liquidity during stress. Candidates who test liquidity using normal-market assumptions understate the risk.
- Placing bonds in the taxable account and equities in the IRA. This is the most common asset location error. Bonds generate ordinary income (high tax rate). Equities generate capital gains and qualified dividends (lower rate). Bonds belong in tax-deferred accounts.
Bottom line
- Every real constraint moves the portfolio off the efficient frontier; the question is whether the deviation is justified.
- Asset size determines which asset classes are accessible (minimums for small portfolios, market impact for large ones).
- Liquidity constraints tighten during stress, exactly when liquidation costs are highest.
- Taxes are the most impactful constraint for taxable investors: asset location (tax-inefficient bonds and REITs in tax-deferred, tax-efficient equities in taxable), tax-loss harvesting, gains deferral.
Exam shortcut
When the vignette describes a taxable client, check asset location first, bonds in the taxable account is the most common error to identify. When the vignette describes an institutional investor adding illiquid assets, stress-test the liquidity by mapping cash demands under a simultaneous equity drawdown and PE capital call scenario. If the accessible liquid assets cover less than 2x the stress-period cash demand, the allocation is too aggressive.
The full lesson (about 3,590 words, 24 min read) adds 2 worked examples, all 8 common mistakes, a self-check, free in the app.
Learning objectives
- real world constraints
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