This research aims to study private equity impact investments based on a comparative analysis of different private equity funds practices. In particular, it examines how the requirements of impact investing are encompassed in private equity investment processes. First, a literature review was conducted to better define impact investing and assess the complementarity of private equity with impact investing. Secondly, a qualitative study was pursued based on a panel of interviews. Interviewees are investment professionals working for private equity firms with interests in impact investing. The analysis of the interviews indicates a certain commonality of the investment methods between the funds paneled whether they are pure player private equity impact investors or traditional private equity firms investing for impact. Beyond the proximity between investment strategies, the research also shows a strong focus on in-house impact targeting and measurement, with little resort to external tools. Such flexibility negatively affects the readability of impact performance from a market perspective. The research concludes impact investing still has to go through a standardization process to gain global recognition as a private equity segment.