Kim Peijnenburg

Ambiguity Aversion and Household Portfolio Choice Puzzles: Empirical Evidence

We test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambiguity preferences using custom-designed questions based on Ellsberg urns. As theory predicts, ambiguity aversion is negatively associated with stock market participation, the fraction of financial assets in stocks, and foreign stock ownership, but it is positively related to own-company stock ownership. Conditional on stock ownership, ambiguity aversion is related to portfolio under-diversification, and during the financial crisis, ambiguity-averse respondents were more likely to sell stocks.

How Much Do Means-Tested Benefits Reduce the Demand for Annuities?

We analyze the effect of means-tested benefits on annuitization decisions. Most industrialized countries provide a subsistence level consumption floor in old age, usually in the form of means-tested benefits. The availability of such means-tested payments creates an incentive to cash out (occupational) pension wealth for low and middle income earners, instead of taking the annuity. Agents trade-off the advantages from annuitization, receiving the wealth-enhancing mortality credit, to the disadvantages, giving up “free” wealth in the form of means-tested supplemental benefits. We find that the availability of means-tested benefits can reduce the desired annuitization levels substantially. Using individual level data, we show that the model’s predicted annuitization rates as a function of the level of pension wealth are roughly consistent with the cash-out patterns of occupational pension wealth observed in Switzerland.

Health Cost Risk: A Potential Solution to the Annuity Puzzle

We find that health cost risk lowers optimal annuity demand at retirement. If medical expenses can be sizeable early in retirement, full annuitisation at retirement is no longer optimal because agents do not have enough time to build a liquid wealth buffer. Furthermore, large deviations from optimal annuitisation levels lead to small utility differences. Our results suggest that health cost risk can explain a large proportion of empirically observed annuity choices. Finally, allowing additional annuitisation after retirement results in welfare gains of at most 2.5% when facing health cost risk, and negligible gains without this risk.

The Annuity Puzzle Remains a Puzzle

We examine incomplete annuity menus, background risk, bequest motives, and default risk as possible drivers of divergence from full annuitization. Contrary to what is often suggested in the literature, we find that full annuitization remains optimal if saving is possible after retirement. This holds irrespective of whether real or only nominal annuities are available. Whenever liquidity is desired, individuals save sizeable amounts out of their annuity income to smooth consumption shocks. Similarly, adding equity-linked annuities to the menu does not increase welfare significantly, since individuals can invest in stocks in order to get the desired equity exposure.

Life-Cycle Asset Allocation with Ambiguity Aversion and Learning

Ambiguity and learning about the equity premium can simultaneously explain the low fraction of financial wealth allocated to stocks over the life cycle and the stock market participation puzzle. Individuals are ambiguous about the size of the equity premium and are averse to this ambiguity, resulting in lower stock allocations over the life cycle, consistent with the data. As agents get older, they learn about the equity premium and increase their allocation to stocks. Furthermore, I find that ambiguity leads to underdiversification, home bias, lower Sharpe ratios, and higher savings. Similar results cannot be obtained by assuming higher risk aversion.

Household Portfolio Underdiversification and Probability Weighting: Evidence from the Field

We explore the relation between probability weighting and household portfolio underdiversification in a representative household survey, using custom-designed incentivized lotteries. On average, people display Inverse-S shaped probability weighting, overweighting the small probabilities of tail events. As theory predicts, our Inverse-S measure is positively associated with portfolio underdiversification, which results in significant Sharpe ratio losses. We match respondents’ individual stock holdings to CRSP data and find that people with higher Inverse-S tend to pick stocks with positive skewness and hold positively-skewed equity portfolios. We show that these choices reflect preferences rather than probability unsophistication or limited financial knowledge.