Hedging Motives and Preferences in the Underdiversification Puzzle

Summary

The document raises a conceptual question about why investors hold concentrated stock portfolios despite arguments for broad diversification. It cites research describing hedging motives and heterogeneous preferences as standard explanations, while also noting that other studies question their limits. The author interprets hedging motives as risk aversion and heterogeneous preferences as differences in individuals’ risk preferences, but is unsure how these ideas explain underdiversification.

The text supplies context through a reported contrast between an often-cited portfolio benchmark of roughly 300 stocks and typical U.S. investor holdings of only a few stocks. It does not answer the question or explain the economic mechanisms linking these motives to concentrated holdings. In particular, it gives no model, empirical evidence, or account of how hedging demand or preference variation changes portfolio choices. It is therefore useful as a statement of the puzzle and its proposed explanatory categories, but not as a resolved treatment of them.

Key ideas

• The underdiversification puzzle concerns investors holding relatively few stocks despite arguments for broad diversification.
• Hedging motives and heterogeneous preferences are cited as standard explanations.
• The author identifies risk aversion with hedging motives and individual risk differences with heterogeneous preferences.
• The document poses the conceptual question but provides no explanation, model, or empirical test.

Tags

# Why "hedging motives" and "heterogeneous preferences" are explanation for "under diversification puzzle"?


# Why "hedging motives" and "heterogeneous preferences" are explanation for "under diversification puzzle"?












Han et al. 2021 documented something relating to the "under diversification puzzle":

> Standard explanations for under diversification include hedging motives and heterogeneous preferences, but several studies highlight the limitations of these explanations

From Statman, 2004, I understand that "under diversification puzzle" is normally, we should hold a portfolio of around 300 stocks but in U.S, the average investor hold is only 3 or 4 stocks.

I understand that "hedging motives" is that risk aversion, meaning investors need to buy some stocks to reduce the risk of the portfolio. "heterogeneous preference" is that each individual investor has their own risk preference. However, given the understanding above, I cannot understand why we can use "hedging motives" and "heterogeneous preferences" to explain the "underdiversification puzzle"

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.