Smart(Phone) Investing? A within Investor-Time Analysis of New Technologies and Trading Behavior

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