This study examines the issues of winner's curse, size effect and bandwagon effect in explaining the under-pricing phenomenon of Malaysian IPOs, for the period from January 2001 to December 2008. The average initial return for the Malaysian private placement IPOs (a proxy for informed investors) is significantly lower than that of the non-private placement IPOs (a proxy for uninformed investors), which gives support to the winner's curse hypothesis, where uninformed investors demand a higher initial return in the absence of informed investors. Using listing board as proxy for size of companies, we find that the smaller the company, the higher the average initial return, thus giving support to size effect, where investors usually demand higher initial return for smaller companies due to their higher perceived risk. The study also finds that the presence of a large number of informed investors as compared to uninformed investors in an IPO exercise will result in an increase in demand for that particular stock in the secondary market, which gives support to the bandwagon effect.