The Role of Public and Private Markets in a Balanced Portfolio

For most of the last century, a "diversified portfolio" meant some combination of publicly traded stocks and bonds. That definition has expanded. Private markets (private equity, private credit, venture capital, real estate, and infrastructure) have grown into a global asset class that institutional investors now allocate to in size, and that qualified individual investors increasingly access.

Understanding what public and private markets each contribute, and where they fit in a balanced portfolio, is one of the more consequential investment conversations of this decade.

Public Markets: Liquidity, Transparency, and Broad Access

Public markets (stocks, bonds, and exchange-traded funds) remain the foundation of most portfolios for good reason:

• Liquidity: Positions can be bought or sold on any trading day at a transparent, market-determined price.
• Transparency: Public companies file quarterly and annual reports, are subject to SEC oversight, and are covered by independent analysts.
• Low cost: Index funds and ETFs provide broad market exposure at expense ratios measured in single-digit basis points.
• Diversification: A single total-market index fund provides exposure to thousands of companies across sectors and geographies.

For the majority of portfolio capital, particularly capital that may be needed within the next 5-7 years, public markets are the right home. They offer the combination of liquidity, transparency, and low cost that no other asset class matches.

Private Markets: Active Ownership and Long-Horizon Compounding

Private markets offer a different value proposition. The core advantages:

• Active ownership: Private equity managers take controlling or significant minority stakes and actively manage the business, improving operations, governance, and capital structure in ways that passive public market investors cannot.
• Access to companies not available publicly: The number of U.S. public companies has declined from roughly 8,000 in the late 1990s to approximately 4,000 today. Many of the fastest-growing companies remain private longer, meaning public-only investors miss a meaningful portion of the value creation cycle.
• Long-horizon compounding: Private fund structures (typically 7-12 year terms) allow managers to execute multi-year value creation plans without the quarterly earnings pressure that public markets impose.
• Diversification: Private real estate, infrastructure, and credit offer return streams with low correlation to public equities, particularly valuable in periods of public market volatility.

The Growth of Private Markets

McKinsey's 2026 Global Private Markets Report projects global private market assets under management to reach roughly $30 trillion by 2034, approximately triple the current level. Infrastructure alone is expected to exceed $1.8 trillion by 2026. This growth is driven by institutional demand for returns above public market benchmarks, and by the structural shift of companies staying private longer.

Manager Selection: The Critical Variable

In public markets, the difference between a top-quartile and bottom-quartile index fund is measured in basis points. In private markets, the difference between a top-quartile and bottom-quartile manager is measured in hundreds of basis points, sometimes thousands. Manager dispersion in private markets is wide, and manager selection often drives more of the outcome than asset-class selection itself.

This is why access matters. The best-performing private market managers are often capacity-constrained and not available to investors without established relationships or institutional-quality due diligence processes.

Allocation Discipline

The most important principle in private market allocation is simple: only capital that genuinely does not need to be touched for 7+ years belongs in illiquid private vehicles. Private investments cannot be sold on demand. Capital calls arrive on the manager's schedule, not the investor's. Distributions come when the manager exits positions, not when the investor needs liquidity.

For investors who can meet the illiquidity requirement, a measured allocation to private markets (typically 10-30% of total portfolio, depending on the investor's liquidity needs and qualification status) can meaningfully expand the return and diversification opportunity set.

Key Takeaways

• Public markets offer liquidity, transparency, and broad diversification at low cost, the right home for most portfolio capital.
• Private markets add active ownership, long-horizon compounding, and access to companies and assets not available publicly.
• Global private market AUM is projected to triple to roughly $30 trillion by 2034, with infrastructure alone exceeding $1.8 trillion by 2026.
• Manager dispersion in private markets is wide. Manager selection often drives more of the outcome than asset-class selection.
• Allocation discipline matters: only capital that genuinely does not need to be touched for 7+ years belongs in illiquid private vehicles.

The Bottom Line

The right question for most investors is not whether to invest in private markets, but how much, with which managers, and under what allocation discipline. For accredited and qualified-purchaser investors, a measured allocation can meaningfully expand the return and diversification opportunity set. For investors whose capital is fully needed in the next several years, public markets remain the right answer.

If you would like to walk through whether and how private markets fit your specific situation, including the suitability considerations that matter most, we are happy to have that conversation.