The traditional IPO

A traditional IPO sells new shares to public investors through investment banks. The banks set a range, collect demand, pick an offering price the night before trading, and the market finds a different price the next morning. That gap is the famous first-day pop.

The big idea

Think of a bake-off, then a roadshow, then an auction that is not quite an auction. Banks compete to lead the deal. Management then tours institutions, and the syndicate builds a book: who wants how many shares at what prices. Banks aim for heavy oversubscription so they can allocate scarce stock to favored accounts.

The analogy breaks at pricing. A house auction sells to the highest bid. An IPO often underprices on purpose so the first trade jumps.

Walking through a $800M offering

The company sells 20,000,000 new shares at a $40 offering price.

Primary proceeds = 20,000,000 × $40 = $800M  (before fees)

Underwriting spreads in a traditional IPO are often on the order of ~3–7% of the offering, plus millions in legal, accounting and audit costs.

The next morning the first trade opens at $56 — a 40% pop.

Market now prices those shares at $56
Cash that actually entered the treasury came from $40

Headline market-cap stories use the trading price. The company raised at $40. Pre-IPO holders who wanted maximum primary proceeds would have preferred a higher offering price. IPO-day buyers preferred the pop. Same event, different winners.

Bill Gurley and other critics argue the pop is partly structural: banks underprice to guarantee a successful deal and reward buy-side clients, transferring value from the company to IPO-day buyers. Defenders call underpricing insurance against a failed deal and a marketing event.

You do not get the offering price. Employees generally cannot buy the IPO allocation, and they usually cannot sell until the lockup ends.

A greenshoe (overallotment) typically lets underwriters sell about 15% more shares to stabilize trading in the first month. It changes final dilution and float.

The S-1 is the highest-signal document before a ticker exists. Early filings are often confidential; a public S-1 later appears on SEC EDGAR. Read risk factors, revenue concentration and how management talks about growth — not only the charts.

Common mistakes

• Treating the first-trade price as what the company raised. Treasury cash came from the offering price, after fees.
• Assuming employees can buy or sell on day one. Allocations go to institutions; sales wait for lockup.
• Skimming the S-1 growth charts and skipping concentration and risk factors. Those sections are where the business actually lives.

Check yourself

The company sells 20 million shares at $40 and opens at $56. How much primary cash did it raise before fees?

$800 million — 20 million × $40, not × $56.

Why do banks often underprice?

To guarantee a successful deal and reward buy-side clients; the pop is the transfer.

Key takeaways

• Banks run the S-1, the roadshow and the book, then set an offering price the night before trading.
• The first-day pop is the gap between that price and the open. Employees do not capture it.
• A greenshoe of about 15% is the usual stabilizer and extra dilution.
• Read the S-1 on EDGAR, not just the pop headlines.

Further learning

A walkthrough of underwriting, the S-1, the roadshow and why day-one price differs from the offering price:

Next: IPO lockups.