This paper finds private equity (PE) firms to have an active monitoring role in stock market-listed companies. Little is known about the governance role of PE investors in publicly listed firms. Using a novel dataset of the ownership structures of firms listed on the German stock market, I find a higher likelihood of forced CEO replacements after poor past firm performance in companies with higher PE ownership. The PE monitoring effect only exists if representatives of the PE firm sit on the board of the portfolio firm. PE ownership is generally associated with higher firm value.