Using data directly from Robinhood, researchers found that users overwhelmingly favor thematic ETFs over broad-based products. : (Bloomberg) -- Day traders getting rich buying trendy companies from solar power to cloud computing are defying two decades of money-losing history in ETFs that follow the approach. Stuffed with overvalued stocks, exchange-traded funds targeting the hottest investment themes actually lost as much as 5% per year on a risk-adjusted basis between 2000 and 2019, according to new research. It should serve as a reminder that good times don’t last, yet the speculative euphoria surrounding thematic funds keeps growing.