CFA Institute's private-markets math argues for TDF sleeves, not menu slots

After running a stylized target-date fund through 10,000 accumulation paths on return data from January 2010 through December 2024, the CFA Institute's Research and Policy Center inserted a 10% allocation to each of five private asset classes one at a time and found that three — private debt, infrastructure, and real estate — ended with lower average balances than a plain public stock-and-bond portfolio, according to the report Private Markets in Retirement Plans: Returns, Risks, and the Importance of Plan Design.

Private equity did the simple thing, returning $1.489 million against $1.316 million for the baseline, a 13% increase in nominal retirement wealth; venture capital also lifted average balances, though InvestmentNews's coverage describes considerably greater volatility. Every one of the five improved risk-adjusted performance, measured by the mean annual Sharpe ratio, and in the three that lowered terminal balances the gain came from a meaningful reduction in volatility. That split is the result worth arguing about: a return trade in private equity and venture capital, a ballast trade in private debt, infrastructure, and real estate.

The split matters for a second reason. On wealth, only two of the five asset classes beat a plain stock-and-bond baseline, and the report is explicit that the benefit depends heavily on which assets are chosen and how the overall fund is designed. Sponsors have spent two years asking whether they can get into private markets; the study answers the question underneath it — what they are buying once they are in.

The practical reading for a plan committee is narrower than the headline. If the objective is wealth, the report supports a private equity sleeve and, for committees with more risk tolerance, venture capital; if the objective is a smoother path, it supports private debt, infrastructure, or real estate, and the sponsor should stop expecting those three to pay for themselves in terminal balances. What the report does not support is treating the five as interchangeable, which is what a single line item labeled private markets on a menu or in an investment policy statement effectively does.

Where the allocation lives decides that: put a 10% private debt or infrastructure sleeve inside a target-date fund and the sponsor is buying volatility reduction through a vehicle it already selects, monitors, and rebalances, while the same allocation on a self-directed menu leaves a participant with a lower expected ending balance in exchange for a smoother ride that never shows up in a quarterly statement. As this publication has argued, private assets will enter DC plans through target-date sleeves rather than standalone menu slots; this report is the arithmetic behind that call.

The sleeve is also where the decision gets made. Collective investment trusts hold 55% of the $5.3 trillion target-date market, and shelf access runs through recordkeepers and the consultants who model glidepaths — an audience that can price a volatility trade and rebalance it on schedule. A menu slot hands the same choice to a participant who has no glidepath to blend it against.

The policy calendar is not cooperating with the research calendar. The Labor Department proposed a rule on March 30, 2026 that would establish a clearer fiduciary framework for alternatives in 401(k) plans, which the coverage frames as reducing regulatory uncertainty for sponsors weighing private assets. This week, senior Democrats including Senator Bernie Sanders urged the Justice Department and the FBI to investigate what the coverage describes as thousands of allegedly fake comments backing the proposal. With roughly $14 trillion in U.S. defined contribution plans, the argument has moved from theory to operations, and a fight over a comment record now sits between the proposal and a final rule.

What research of this kind cannot do is hand the Labor Department the thing its framework actually needs. The safe harbor for private assets in DC plans rests on a meaningful benchmark that private markets have not produced, and the latest deal data has not closed that gap. A mean annual Sharpe ratio computed across 10,000 modeled accumulation paths is a legitimate research construct and a useful way to compare asset classes; it is not the yardstick a plan sponsor can cite when a participant or a regulator asks how the private sleeve was evaluated. The CFA Institute study strengthens the portfolio case for private assets in DC plans considerably. It does nothing for the documentation case. The documentation case is the one that has been stuck.

The results the report has not yet put numbers to are the ones that would settle the operational question. It also tested portfolios holding two private asset classes at once, pairing a growth-oriented asset such as venture capital or private equity with a second sleeve; what those pairings produced, the coverage does not say. That is the configuration a glidepath would actually run, a growth engine beside a ballast engine, and its outputs would show whether private debt, infrastructure, and real estate earn a permanent place in the sleeve or get bought only when a sponsor can afford to trade terminal wealth for a smoother path. Until those figures surface, the comparison that matters is the one already printed: $1.316 million, the public-markets baseline that three of the five private allocations failed to beat.