A recent theory by Gennaioli, Shleifer, and Vishny (2015) proposes that trust is an important component for delegated investing. This paper tests the theory in a laboratory experiment. Participants first play a trust game. Participants then act as investors who have to make two separate, delegated investment decisions. Using the amount returned in the trust game as measure of trustworthiness, we show that investors are willing to take substantially more risk when a money manager is more trustworthy, even if this manager charges higher costs. The willingness to take more risk and pay higher costs is increasing in the difference in trustworthiness of the two money managers. This finding is robust to different specifications of the difference in trustworthiness.

We use individual-level data on all security trades, holdings, spending, and income from an online retail bank. We study the effects of an exogenous change in the displayed purchase prices of the mutual funds in individuals' portfolios. We find that individuals are more likely to sell what we call fictitious winners, i.e., funds that are winners under the newly displayed purchase price but are losers under the actual purchase price. We also document that individual consumption increases in response to realizing fictitious capital gains. We thus document a causal link among purchase prices, trades, and consumption using observational data and find that the trading and consumption results are more prevalent for less-informed investors. We thereby document a marginal propensity to consume out of (confused) capital gains, which is informative about the literature on consumption out of stock market wealth.

Using transaction-level data from two German banks, we study the effects of smartphones on investor behavior. Comparing trades by the same investor in the same month across different platforms, we find that smartphones increase purchasing of riskier and lottery-type assets and chasing past returns. After the adoption of smartphones, investors do not substitute trades across platforms and buy also riskier, lottery-type, and hot investments on other platforms. Using smartphones to trade specific assets or during specific hours contributes to explain our results. Digital nudges and the device screen size do not mechanically drive our results. Smartphone effects are not transitory.