This paper estimates the short-run performance of IPOs issued on the Karachi Stock Exchange in Pakistan. The present study extends the existing literature concentrating on the degree of underpricing over a 3-month period lasting from the listing date to the 3-month anniversary showing significant evidence of IPO underpricing. The analyses support the investors’ sentiment and underwriters’ prestige hypothesis but not ex-ante uncertainty. The EBA technique has been used to examine fifteen explanatory variables of IPO underpricing. The study finds that the aftermarket risk level of the IPO, the oversubscription ratio, the offer price, the return on assets, post issue promoters’ holding and size of the firm are six robust determinants of IPO underpricing.Este trabajo estudia el desempeño de corto plazo de las ofertas públicas iniciales de acciones en la bolsa de Karachi (Pakistán), mostrándose subvaluaciones de precios desde la fecha de la oferta hasta los tres meses. Se encuentra soporte a las hipótesis de percepción y prestigio, pero no de incertidumbre ex ante. La técnica de análisis de límites extremos permite analizar quince potenciales determinantes de la subvaluación de manera robusta.