Public-Equity-Funded Private Allocation
Add private equity without expanding the portfolio’s risk budget
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 98%
The mechanism treats private equity as a replacement for part of the public-equity sleeve rather than an addition to the total portfolio. First identify the portfolio’s equity allocation, then select what proportion of that sleeve should become private. A 60/40 investor assigning 30% of the equity sleeve to private equity would hold 18% private equity, 42% public equity, and 40% bonds. This preserves the original 60% total-equity exposure while introducing companies unavailable in public markets. Because the allocation is funded from public equity, the investor does not automatically enlarge the portfolio’s risk budget. The method must still account for illiquidity, capital calls, manager quality, and the investor’s time horizon.
Origin
Extracted from Masters in Business, where Fran Kinniry explained Vanguard’s portfolio-construction approach to private equity.
Core principles
- 01Treat private equity as equity, not as a separate risk bucket
- 02Fund private holdings by reducing public equity
- 03Preserve the portfolio’s fixed-income allocation
- 04Size the allocation as a percentage of the equity sleeve
- 05Use private equity only with a sufficiently long horizon
How to run it
- 1
Confirm a Long Horizon
Verify that the investor can leave the allocated capital committed through the private-equity holding period. Reserve sufficient liquid assets for foreseeable spending and emergencies.
Pro tip Model adverse cash needs before deciding the allocation.
Watch out Do not use this method when the investor may need to sell during market stress.
- 2
Set the Existing Risk Budget
Document the current split between equities and fixed income. Treat this allocation as the risk-budget constraint rather than adding private equity on top.
Pro tip Start from the strategic allocation, not the portfolio’s temporary market weights.
Watch out Adding private equity without reducing another risky asset can unintentionally increase exposure.
- 3
Choose the Private Share of Equity
Select the percentage of the equity sleeve—not the whole portfolio—to allocate to private equity. Base the percentage on liquidity, access, diversification, and governance capacity.
Pro tip State the decision in both sleeve and total-portfolio percentages to prevent confusion.
Watch out Do not confuse 30% of equities with 30% of the total portfolio.
- 4
Fund from Public Equity
Calculate the private allocation and subtract the same amount from public equities. Keep fixed income unchanged unless a separate allocation review justifies changing it.
Pro tip For a 60% equity sleeve, a 30% private share equals 18% of the total portfolio.
Watch out Avoid funding an equity-like private asset from defensive bonds merely to preserve public stocks.
- 5
Implement and Govern
Commit capital through diversified, carefully selected managers and monitor capital calls, distributions, and total equity exposure. Reassess liquidity as circumstances change.
Pro tip Integrate private and public holdings into one portfolio report.
Watch out Reported private valuations may be stale and should not be mistaken for low economic risk.
In the wild
A long-horizon investor has 60% in public stocks and 40% in bonds. The adviser assigns 30% of the equity sleeve to private equity. Multiplying 60% by 30% produces an 18% total-portfolio private allocation, so public equity falls to 42% while bonds remain at 40%.
→ The investor gains private-market exposure while retaining the original 60% total-equity risk budget.
An investor proposes adding 10% private equity to an existing 70/30 portfolio without selling anything. The adviser instead moves 10 percentage points from public equity, producing 60% public equity, 10% private equity, and 30% bonds.
→ The revised implementation avoids increasing total equity exposure to 80%.
Common mistakes
Treating Private Equity as an Add-On
Adding private equity without reducing public equity expands the risk budget and changes the strategic portfolio.
Using the Wrong Denominator
A percentage of the equity sleeve is smaller than the same percentage of the entire portfolio; confusing them creates a major sizing error.
Ignoring Liquidity Needs
A mathematically sound allocation can still be unsuitable when the investor may need the committed capital early.
Is it for you?
Best for
It is best for long-duration investors using a professionally constructed multi-asset portfolio.
Not ideal for
It is not ideal for investors with near-term spending needs, uncertain liquidity requirements, or concentrated portfolios.
From the transcript
“We would think that the private equity allocation comes out of your public equity allocation.”
“So now they would be eighteen percent private equity and forty two percent public equity maintaining their in bonds.”
“you're not really increasing the risk budget of the portfolio.”
From the episode
Fran Kinniry on Private Equity Portfolio Investments (Podcast)
Fran Kinniry