Leveraging granular trade flow data from a large open economy, South Korea, and exploiting non-fundamental price changes, we present a novel empirical evaluation of price elasticity among different investor types. By employing retail ETF flows and price pressures induced by the hedging motives of derivatives issuers as instrumental variables, we provide an estimate of price inelasticity for various investors, including institutions, retail investors, and foreigners. We then exploit the variation in the strictness of institutional investors’ mandates to test whether such mandates are linked to price inelasticity, as suggested in the literature. Finally, by applying the demand system outlined by Koijen and Yogo (2019), we examine the influence of retail investors’ demand on a range of asset prices. This study illuminates the distinct roles various investor types play in asset pricing, with an emphasis on retail investors.