What Drives Variation in Investor Portfolios? Evidence from Retirement Plans

We document new patterns in investment behavior using a comprehensive dataset of 401(k) plans from 2009 through 2019. We show that there is substantial heterogeneity in asset allocation across plans, and that these differences are systematically predictable by sector of employment and demographic characteristics. For example, higher income and education is associated with more exposure to equities, while a greater share of minorities and retirees is associated with less equity exposure. These patterns cannot be rationalized by differences in investment options or plan participation. To understand observed investment behavior, we use a revealed preference approach that allows us to recover heterogeneity in investors’ (subjective) expectations and risk preferences. We find that differences in expectations play an important role in explaining portfolios. Further, we show that investors appear to form expectations based on local sources of information such as county-level GDP growth, home prices, and employer past performance. Overall, our findings are consistent with a model in which heterogeneity in investor expectations reflects idiosyncratic experiences and local environments.