Secondary buyouts represent now over 60% of the overall buyout activity. In this paper we investigate the possible determinants of such a spectacular growth. We show that first-round buyers generate a large and significant abnormal improvement in operating performance. In contrast, SBO operating growth is not different from that of the peer group. Returns to secondary PE investors are positive but significantly lower than those of first round buyers. We test several alternative drivers of SBOs and find that favorable credit market conditions and PE reputation drive secondary investment volume.