4.9 Long-run performanceWhen measuring the long-run abnormal returns on IPOs, the same performance measurement issues as with SEOs come up.As G.W. Schwert notes in his chapter in this Handbook, there is a tendency for anomalies to disappear once they have been identified.Whether this is because the original anomaly occurred by chance during some sample period, or because the market learns and begins to price securities differently, is unclear.In Table 9, the annual returns on IPOs in the five years after issuing are reported, along with benchmark returns using either size or style matching.The style matches are based upon size (market cap) and book-to-market matching The numbers reported in Table 9 are displayed in Figure 2.