Financial economists have intensely debated the performance of IPOs using data after the formation of Nasdaq. This paper sheds light on this controversy by undertaking a large, out-of-sample study: We examine the performance for ¢ve years after listing of 3,661 U.S. IPOs from 1935 to 1972.The sample displays some underperformance when event-time buy-and-hold abnormal returns are used.The underperformance disappears, however, when cumulative abnormal returns are utilized. A calendar-time analysis shows that over the entire period, IPOs return as much as the market. The intercepts in CAPM and FamaF rench regressions are insigni¢cantly di¡erent from zero, suggesting no abnormal performance. RITTER (1991) AND LOUGHRAN AND RITTER (1995) document severe underperformance of initial public o¡erings (IPOs) during the past 20 years. In discussing these results, they suggest that investors may systematically be too optimistic about the prospects of ¢rms that are issuing equity for the ¢rst time.Their results have inspired countless articles in the popular press about the danger of investing in IPOs, as well as academic research that has shown that underperformance extends to other countries as well as to seasoned equity o¡erings.The results concerning IPO performance, however, are controversial. Brav and Gompers (1997) show that ¢rms that go public do not perform worse than benchmarks matched on the basis of size and book-to-market ratios. In addition, they show that value weighting IPO returns dramatically reduces the measured underperformance. Finally, they argue that weighting returns in event time by the number of IPOs may overstate underperformance. Schultz (2003) argues that if more ¢rms go public after stock prices have risen, event-time analyses may indicate that IPOs underperform, even if the ex ante expected return of these o¡erings is zero.