We construct a novel measure of partisan corporate speech using natural language processing techniques and use it to establish three stylized facts. First, the volume of partisan corporate speech has risen sharply between 2012 and 2022. Second, this increase has been disproportionately driven by companies adopting Democratic-leaning language, a trend that is widespread across industries, geographies, and CEO political affiliations. Third, partisan statements are followed by negative abnormal stock returns, with significant heterogeneity by shareholders’ alignment with the statement. We propose a theoretical framework and provide suggestive empirical evidence that these trends are driven by a shift in investor preferences.