Using a large set of trading accounts, we study the determinants of retail investing in passive Exchange Traded Funds (P-ETFs). Controlling for investor characteristics related to their risk-return profile, trading activity, and socio-demographics, we show that the probability and magnitude of P-ETF investing by retail investors can be explained by financial knowledge , financial experience, and
... [Show full abstract] behavioral biases such as overconfidence and local bias. We also show that the more active P-ETF users hold a lower number of stocks and modify the composition of their stock portfolio less extensively, pointing to a substitution effect between stocks and P-ETFs.