IPO Underpricing and the First-Day Pop

A company sells shares to the public at $20 in its IPO. The next morning, the stock opens trading at $26 and closes the day there. Every investor who got an allocation at $20 just made 30% before lunch, and the company that sold the shares effectively left $6 a share — potentially hundreds of millions of dollars — on the table that it could have raised instead.

This gap between the IPO offer price and the first day's closing price is called underpricing, and the jump itself is the first-day pop. It is one of the most studied and stubbornly persistent patterns in all of corporate finance: IPOs are underpriced on average, by a lot, and have been for decades, across almost every country with public markets.

Why underpricing persists

Several explanations coexist, and most academics believe they all contribute something.

• Information asymmetry (the "winner's curse"). Some investors in the IPO know more about the company than others. Uninformed investors risk getting large allocations only in deals the informed investors correctly avoid — so underwriters underprice broadly to keep uninformed demand in the pool at all.
• Compensating investors for revealing demand. During the roadshow, big institutional investors tell the underwriter how much they'd pay. Underwriters reward that honesty with underpriced allocations, because if truthful demand signals got you nothing extra, investors would just bid low and hope.
• Signaling quality. A company that deliberately leaves money on the table can afford to, because it plans to raise more later at a higher price in a secondary offering — underpricing signals confidence that the market will re-rate the stock upward once it trades.
• Litigation avoidance and price support. A stock that opens below its offer price generates lawsuits and reputational damage for the underwriter; pricing conservatively is cheap insurance against that outcome.

Worked example

A company sells 20 million shares in its IPO at an offer price of $20, raising $400 million. The stock opens trading and closes its first day at $26.

1. Underpricing (percentage). $(26 - 20)/20 = 0.30$, a 30% first-day pop — a large one by historical standards, though not unusual for a hot sector.
2. Money left on the table. $(26 - 20) \times 20\text{m} = 120$, i.e. $120 million that would have gone to the company (and its selling shareholders) had the deal been priced at the level the market was actually willing to pay.
3. If the underwriter's fee was 5% of the $400 million raised ($20 million), the money left on the table is six times the entire fee the company paid for the underwriting service — the reason underpricing is such a contentious topic between issuers and their banks.

What this means in practice

Companies and their boards watch underpricing closely because it is a direct, measurable cost of going public through a traditional book-built IPO, and it is one reason some companies choose a direct listing or a Dutch auction instead, both of which let the market set the opening price rather than a fixed offer price agreed the night before trading starts. Underwriters, for their part, argue that a modest, controlled pop is a feature: it rewards the investors who supported the deal and builds a stable, well-distributed shareholder base for the stock's first weeks of trading.