Using plausibly exogenous variation in the ability to short-sell, we provide evidence that public information is predominantly impounded into prices via trade. Studying the role of trade in the context of publicly-observed cash flow news, we find that only 6% of total price discovery is realized on announcement days with low trade. A portfolio strategy that focuses on stocks with high announcement-day trade yields monthly alpha of 2.46%. In contrast to the predictions of the literature on no-trade equilibria, our evidence suggests that trade plays a significant role in price discovery.