Initial public offering (IPO) underpricing is a costly practice that decreases the IPO proceeds accruing to the issuing firms and can derail a firm's growth objectives. The purpose of this correlational study was to determine the relationship between share retention, underwriter reputation, and IPO underpricing among a population of IPOs issued in Jamaica. The efficient market hypothesis served as the theoretical framework for this study. Archived data for 52 IPOs issued in Jamaica from 1986 to 2018 were collected and Spearman's correlation matrix and heteroscedasticity-consistent standard errors regression analysis were applied. The outcomes of this study indicated no significant relationship between share retention and IPO underpricing, α = .1 and α = .05, r = .059, p = .35; however, there was partial acceptance of the alternative hypothesis that underwriter reputation is related to IPO underpricing at α = .1, r = .234, p = .055, but not α = .05. Additionally, underpricing was higher for IPOs supported by the high reputation underwriters, and share retention was a slightly better predictor of IPO underpricing for this group of IPOs, R2 = .02, p = .31 versus R2 = .01, p = .75. Finally, the overall model indicated that the independent variables did not jointly explain IPO underpricing, F(2, 45) = .78, p = .455, R2 = .032. The results of this study might contribute to social change because successful IPOs can increase employment opportunities as well as improve income distribution and socioeconomic indicators for the communities served by IPO firms.