Alpha Relative to Simple Diversified Portfolios

How much should investors who hold a conventionally diversified portfolio (stocks and bonds) be willing to pay for and an additional equity or bond fund that outperforms its benchmark (provides alpha)? In their May 2025 paper entitled "How Much Should You Pay for Alpha? Measuring the Value of Active Management with Utility Calculations", Andrew Ang and Debarshi Basu estimate the amount an investor is willing to pay for access to an active equity or bond mutual fund, starting from an optimal stocks-bonds portfolio. Specifically, they:

1. Empirically estimate investor risk aversion for a given stocks-bonds base portfolio, focusing on a 60-40 S&P 500 Total Return Index-Bloomberg US Aggregate Bond Index portfolio.
2. Add one of 1,203 active U.S. large-capitalization mutual funds in the Morningstar database or one of 47 fixed income mutual funds in the Morningstar Core Plus US bond category to the base portfolio.
3. For each added fund, compute the utility benefit (certainty equivalent or willingness-to-pay) of adding it.

For robustness, they repeat this analysis for different stocks-bonds base portfolios and different assumptions about equity-bond correlations. Using monthly returns for the selected indexes and mutual funds during January 2016 to December 2024, they find that: