This article shows that contemporaneous and lagged air pollution negatively affects the likelihood of German individual investors to log in and trade in their brokerage accounts, using intraday data and controlling for investor-, weather-, traffic-, and market-specific factors. A 1 SD increase in air pollution leads to a 1.3 percent reduction in the probability of logging in, which is larger than the response to a 1 SD increase in sunshine. We argue that changes in air pollution affect productivity in cognitively demanding tasks, such as trading. Our results are robust to macroeconomic productivity shocks, nonlinearities, or measurement error.

We explore the impact of weather on trading by individual investors. Over a time span of 94 months, we analyze daily trading records of individual investors. Controlling for various investor- and market-specific factors, we find a two-fold effect of weather. We first observe that investor sentiment, as measured by purchases relative to sales, is significantly higher on days with good weather. In addition, we find that retail investors generally trade more on bad weather days. This result is consistent with the notion that retail investors incur an opportunity cost for spending time trading on days with good weather.

The 2020 CARES Act directed large cash payments to households. We analyze households’ spending responses using data from a Fintech nonprofit, exploring heterogeneity by income, recent income declines, and liquidity as well as linked survey responses about economic expectations. Households respond rapidly to payments, with spending increasing by about $0.14 per dollar during the first week and plateauing around 0.25–0.30 over 3 months. In contrast to previous stimulus programs, we see little response of durables spending. Households with lower incomes, greater income declines, and less liquidity display stronger responses whereas households that expect employment losses and benefit cuts display weaker responses.

Using data from a large German brokerage, we find that individuals investing in passive exchange-traded funds (ETFs) do not improve their portfolio performance, even before transaction costs. Further analysis suggests that this is because of poor ETF timing as well as poor ETF selection (relative to the choice of low-cost, well-diversified ETFs). An exploration of investor heterogeneity shows that though investors who trade more have worse ETF timing, no groups of investors benefit by using ETFs, and no groups will lose by investing in low-cost, well-diversified ETFs.