Glossary
First-Day Pop
The percentage gain from an IPO's offer price to its closing price on the first day of trading.
The first-day pop measures how much a stock rises on its first day of public trading relative to the IPO offer price. A large pop is sometimes celebrated as a successful debut, but it also represents money the issuer left on the table — capital that could have been raised at a higher offer price.
The long-running academic literature on IPO underpricing finds an average first-day gain of roughly 15–20% in the US, with significant variation across vintages and sectors. The 2020–2021 cohort featured several debuts above +50%; the post-2022 cohort has generally been more measured.