The biggest IPOs ever, and the waves of new listings

The giants: every US IPO of $5 billion or more

Since 1997, 12 IPOs on US exchanges have sold at least $5 billion of stock at the offering price. The first was UPS in 1999, with $5.5 billion; 4 of the 12 came in 2020 or later. Each building below is one of them, in the order they happened, as tall as the money paid for the shares on the day they were priced.

SpaceX stands apart: it sold more than the next 4 biggest US IPOs together — Alibaba, Visa, Facebook and General Motors, $71.4 billion in all. For scale, the table adds one deal from outside the US: Saudi Aramco sold $25.6 billion of shares on the Saudi Exchange (Tadawul) in December 2019, more than any US IPO except SpaceX’s.

The lighter roofs are extra shares. Once the price is set, the underwriters may buy more shares from the sellers at the same price (the over-allotment, or “greenshoe”, option) if demand holds. With them, SpaceX sold $86.2 billion rather than $75.0 billion. At UPS, AT&T Wireless and Kraft Foods the option went unused; for Facebook, Uber and Saudi Aramco, no company filing we read gives the number, so only the shares in the prospectus count. After inflation (the switch below), old deals grow: UPS’s $5.5 billion of 1999 is $10.9 billion in Oct 2026 dollars.

Who held the title

Among US IPOs of $5 billion or more, 5 deals have held the title of the biggest since UPS in 1999: UPS (1999), AT&T Wireless (2000), Visa (2008), Alibaba (2014) and SpaceX (2026). SpaceX has held it since June 2026.

Alibaba held it longest: 11 years and 8 months, from September 2014 to June 2026. UPS lasted 5 months before AT&T Wireless took the title. After inflation, the line of holders is the same.

Raised in one day

An IPO’s money changes hands at one price, on one day. Set against the World Bank’s GDP — the value of everything a country produces in a year — the biggest deals are the size of whole economies. Each bar shows how many of the world’s economies the deal outgrew in its year.

IPO waves: how many companies go public

Counting every company’s first priced public offering in SEC filings (the rule is in the method below), 240 companies a year went public on US exchanges on average from 1997 to 2025. The average hides wild swings.

The dot-com years brought 439 IPOs in 1999 and 345 in 2000. After the bubble burst, the count fell to 90 in 2001, 79% fewer than in 1999, and to 65 in 2003. (What the bubble looked like in prices: Bubbles.)

2009 was the quietest year, with 48 IPOs, as the financial crisis froze the markets. The record year is 2021: 1,000 IPOs, 4.2 times the average. Then the tide went out: 171 in 2022, 83% fewer.

The SPAC boom

A SPAC — a special purpose acquisition company, or blank check company — goes public with no business at all. It sells shares, keeps the money in a trust and has a limited time to find a private company to merge with; the merger takes that company public without an IPO of its own. The SEC files such shells under one industry code, “blank checks”, which is how we tell them apart.

For years SPACs were a niche: 354 from 1997 to 2019 together. Then came 245 in 2020 and 596 in 2021 — 2.4 times as many in two years as in all the years before. In 2021, SPACs were 60% of all IPOs: 1.5 for every operating company.

The busiest month on record was March 2021: 159 IPOs, 118 of them SPACs. On the busiest single day, November 12, 2021, 20 companies filed their final IPO prospectus (9 SPACs). The boom ended almost as fast: 81 SPACs in 2022 and 31 in 2023; in 2025 there were 141. Who collected the fees and who sold shares in such booms is the subject of Who profits from bubbles.

Every month since 1997

Each square is one month; the darker, the more IPOs, and the waves show as dark bands. IPOs are rarest in January, with 13.9 in an average year, and most common in October, with 26.0.