Madison Air Solutions Corp. shares rose 19% after the company raised $2.23 billion in the biggest US listing of an industrial firm in close to three decades.
Shares of the provider of ventilation and filtration systems opened at $32, compared to the initial public offering price of $27 each. The company sold 82.7 million shares after marketing them for $25 to $27 apiece.
The trading gives the Chicago-based company a market value of $15.6 billion based on the number of outstanding shares listed in its filings.
The IPO is the biggest in the US by an industrial company since United Parcel Service Inc. raised $5.5 billion in 1999, according to data compiled by Bloomberg. The courier went public during the rise of online commerce and found favor with investors hungry for stocks linked to the internet.
Madison Air is also seen as way to get exposure to the cutting edge of technology, this time the artificial intelligence boom that's powered a three-year bull market in US stocks. The company's business includes selling liquid, hybrid and air cooling products for data centers, and it's said that the construction of those computing hubs -- as well North America's aging housing stock and reshoring of advanced manufacturing -- is fueling growth in the estimated $40 billion market for specialized air systems.
"Anything associated with AI tends to get a premium," said Rob Thummel, a portfolio manager for the Tortoise AI Infrastructure ETF. "The question is, is it pure-play enough? And I guess that's what investors will decide."
The IPO is the latest, and the largest, in a series of splashy debuts from industrial firms with a tie to the buildout of data centers. Shares of Legence Corp. surged 148% from the engineering company's September IPO through Wednesday, while power-equipment maker Forgent Power Solutions Inc. climbed 20% since debuting in February.
A key part of the pitch for SpaceX, whose IPO could be the biggest of all time, is Elon Musk's dream of putting data centers in space.
AI Enthusiasm
Shares of publicly traded HVAC companies have been swept up in enthusiasm about AI. Comfort Systems USA Inc. surged more than 360% during the 12 months ending Wednesday, while Modine Manufacturing Co. roughly tripled.
"These aren't your parents' or grandparents' industrials. There's a heavy slant towards technology, and that leads to greater volatility," but also increases the potential upside, said Dan Ahrens, portfolio manager of the AdvisorShares HVAC and Industrials ETF.
Madison Industries formed Madison Air through a series of acquisitions beginning in 2017, its website shows. It had more than 8,650 employees at the end of last year.
The company had net income of $124 million on revenue of $3.34 billion for 2025, compared with net income of $236 million on revenue of $2.62 billion a year earlier. Madison Air's top 10 customers accounted for about 32% of revenue last year.
After the IPO, founder Larry Gies was set to control the company through ownership of all of its super-voting shares, according to filings. Madison Industries, which is controlled by Gies, agreed to buy $100 million such shares from Madison Air in a concurrent private placement at the IPO price, a statement earlier showed.
Morgan Stanley Investment Management, Durable Capital Partners LP and HRTG GPE LLC had expressed interest in buying as much as $525 million of shares in the offering, according to the filings.
The offering was led by Goldman Sachs Group Inc., Barclays Plc, Jefferies Financial Group Inc. and Wells Fargo & Co. The shares trade on the New York Stock Exchange under the symbol MAIR.