The Association between Underwriter Lockup and KOSDAQ IPO Initial Returns

This paper examines the effect of unique underwriter lockup on the initial returns of an initial public offering (IPO) in the Korean Securities Dealers Automated Quotation (KOSDAQ). Underwriter lockup induces underwriters to underprice IPOs and stabilize aftermarket prices. The inducement is explored with respects to the mixtures of distributions of the initial returns consistent with underpricing and stabilization. Whether the inducement is meaningful when other factors are controlled is also explored. These explorations provide evidence that underwriter lockup leads to more positive average initial returns in the three aftermarket months.