Nearly 40% of IPO firms redact information from their SEC registration filings. These firms exhibit characteristics consistent with the need to shield proprietary information from potential rivals. They experience greater underpricing, but pre-IPO insiders reduce underpricing-related wealth...

We document the frequent use of lockup agreements in seasoned equity offerings (SEOs), and examine the determinants of their use, duration, and early release. From 1996 through 2006, 93.8% of all SEOs included lockups, which is comparable to the 96.6% lockup rate for IPOs during the same period....