This article studies the political preferences of chief executive officers (CEOs) of public companies. We use Federal Election Commission records to compile a comprehensive database of the political contributions made by more than 3800 individuals who served as CEOs of Standard & Poor's 1500 companies between 2000 and 2017. We find a substantial preference for Republican candidates. We identify how this pattern is related to the company's industry, region, and CEO gender. In addition, we show that companies led by Republican CEOs tend to be less transparent to investors with respect to their political spending. Finally, we discuss the policy implications of our analysis.