I provide causal evidence that textual complexity a↵ects investor and market behavior, using two complementary settings. First, examining field data with randomization from Seeking Alpha, I find that a standard-deviation increase in headline length (negativity) leads to 12%-fewer (2%-more) views. The e↵ects are larger for less-sophisticated investors. Second, examining firm-earnings releases, I find a market e↵ect by instrumenting title length with company-name length. A standard deviation increase in length leads to 5%-lessannouncement turnover, 50-basis-points-tighter-intraday-price ranges, and 40-basis-pointsreturn underreactions, correcting within one month.