We examine the impact of ownership structure on the post-performance of Korean firms that go public as the result of a reverse merger. Although a reverse-merger announcement has positive cumulative abnormal returns (CARs), we find that 24.8% of reverse-merged firms become delisted because of poor post-performance, seemingly due to the agency problem. We also find that expected changes in management after a reverse merger positively affect the CARs of public target firms around the time of the reverse-merger announcement. However, the post-performance of reverse-merged firms is relatively poor compared to firms that undertake regular initial public offerings. Further, we find that ownership concentration alleviates poor performance following a reverse merger.