SUMMARY
In the most common mechanism for price stabilization in IPOs, the underwriter distributes stocks in excess of what was contracted (overallotment) and eventually covers this short naked position by purchasing stocks in the secondary market (Aftermarket short covering , ASC). This mechanism can be used to avoid price drop or price volatility. This article provides a description of such activity in Brazil. We investigate the determinants of price stabilization in three aspects: amount overallotted, occurrence of ASC and its intensity. Our results indicate that price stabilization is an important activity in Brazilian IPOs and quite similar to that occurring in the US. The three different aspects of price stabilization have different determinants. The amount overallotted depends only on the ex-ante demand conditions. ASC occurs mostly on IPOs characterized by high risk, low ex-ante demand and carried by reputable underwriters. The intensity of the ASC increases with the riskiness and decreases with the ex-ante demand. None of the existing models fully explain these results.