Six old-economy stocks hit $100B+ valuations on AI boom

When GE spun off its power-generation unit, Vernova, in early 2024 at a $39 billion（約6.2兆円） market cap, few anticipated it would nearly eightfold to $288 billion（約46兆円） by July 21, 2026. Yet Vernova's trajectory was just one example of a broader phenomenon: six formerly sleepy industrial and tech companies hit $100 billion（約16兆円） valuations by seizing on the AI infrastructure boom. The term "AI Centurions" captures this cohort, rooted in the Latin "centum" for 100—a numerical theme that threads through each member: all sport valuations exceeding $100 billion（約16兆円）, all achieved annualized stock gains above 100%, and as of July 21, five ranked in the top 100 U.S. companies by valuation, with Vertiv standing at 101st.

Vertiv, led by executive chairman Dave Cote (the former Honeywell CEO who had generated returns 2.5 times the S&P 500 trajectory), exemplifies the turnaround narrative. In 2020, Cote and Goldman Sachs acquired Vertiv from private equity for $4 billion（約6400億円）; its predecessor was a despised Emerson Electric division that "hated the business and hated the industry," in Cote's words. But Cote sensed opportunity in the AI data center buildout. Working with Nvidia, Vertiv engineered a breakthrough: a water and glycol cooling system that directs coolant directly over GPU chips instead of using traditional air cooling, maintaining processors at ideal temperatures as data centers deployed far greater hardware density than ever before. The results have been dramatic. In 2025, Vertiv grew sales 31% to $10.2 billion（約1.6兆円） and operating profit sixfold to $2.1 billion（約3400億円）. Cote is bullish on durability, telling Fortune: "I'm convinced that this AI data center expansion is essential to the digital age, and will go on for a long time."

Seagate Technology, founded in 1978, also needed reinvention. After thriving as a hard-disk-drive supplier to early IBM PCs, it stumbled during COVID with excess inventory and swung from strong FY 2019 profits to a loss in FY 2023. But in early 2024, it launched HAMR (a new architecture on its Mozaic platform) that uses lasers to heat disks during writing, enabling super-dense data packing and overcoming traditional physical limits. The payoff was immediate: in Q3 (ended April 3), Seagate shipped 199 exabytes to data centers, up 39% year-over-year, and revenues jumped 44%, while gross margins hit 47%, up 11 percentage points. Western Digital, Seagate's fierce competitor and fellow hard-drive duopolist (the two command an estimated 80% of global HDD business), took a similar path: it re-engineered drives for massive AI workloads and benefited from a seismic shift in pricing. For years, prices had declined ~10% per terabyte annually; now, orders outpace supply so severely that Western is sold out through 2026 and locking in long-term contracts for 2027–2028. Prices have climbed as much as 50% since the start of last year. Western swung from a $1.7 billion（約2700億円） FY 2023 loss to $6.4 billion（約1兆円） in profit over the past four quarters, with March-quarter gross margins reaching 51%.

In February 2025, Western spun its solid-state drive business into Sandisk, a separate, fully public entity. The separation proved brilliant timing. While HDDs grow fast, SSDs are accelerating even quicker because data centers need vast flash memory for inference and training workloads and cannot get supply fast enough to clear bottlenecks. The shortage is raising prices and propelling Sandisk's ascent; it is also developing High Bandwidth Flash (HBF) technology to address future demand. AppLovin, the sole non-hardware member, is an AdTech platform that reaps gains from AI-driven acceleration in processing capacity, enabling it to rank atop mobile app and game marketing and monetization. Over the measurement period (mid-July 2023 to July 21, 2026, or shorter for GE Vernova and Sandisk due to later public debuts), their valuations ranged from $114 billion（約18兆円） (Vertiv) to $288 billion（約46兆円） (GE Vernova), with combined value jumping from $90 billion（約14兆円） to nearly $1 trillion（約160兆円）—a $900 billion（約140兆円）-plus increase that accounts for roughly 3.5% of the S&P 500's total market-cap growth during that span. Their annualized returns, averaging 145% at the median and exceeding 100% for all six, are more than quadruple the Magnificent Seven's ~30% gain.

Yet this success rests on an assumption: relentless growth in AI capex. Infrastructure spending exploded from $35 billion（約5.6兆円） in 2023 to a $650 billion（約100兆円） run-rate in 2026 and is projected to climb to $1.0 to $1.1 trillion（約180兆円） by 2027. Their price-to-earnings multiples—ranging from 29 for GE Vernova to 88 for Seagate—imply the market expects strong profit expansion to continue. Any meaningful reduction in AI spending or slowdown in its pace could send shares sharply lower, especially given the premium valuations now commanded.

The emergence of the AI Centurions reflects a historic reset in manufacturing valuations. Three years ago, in mid-2023, these six companies occupied the underachiever category—Seagate and Western Digital had flat share prices over the prior decade, Vertiv's original franchise was axed by its parent for poor performance, and none ranked in the top 300 U.S. companies by valuation as recently as spring 2024. Their turnaround hinged not on financial engineering but on breakthrough products designed to solve concrete bottlenecks created by hyperscalers' rush to build AI data centers. Vertiv's water-cooling system, for instance, emerged from direct collaboration with Nvidia to understand what hyperscalers needed; Seagate's HAMR technology overcame physical limits to hard-drive capacity by using lasers during data writing. These innovations arrived at precisely the moment when demand for data center infrastructure became acute and supply could not keep pace.

The scale of value creation is striking: their combined valuation jumped from $90 billion（約14兆円） to nearly $1 trillion（約160兆円）, accounting for roughly 3.5% of the entire S&P 500's market-cap rise since mid-2023. On an annualized basis, their 145% median stock gain dwarfs the Magnificent Seven's ~30% return, and all six exceeded 100% annual gains—a cohort threshold that defines the "Centurion" label. As of July 21, 2026, four of the six (GE Vernova, Western Digital, Seagate, and Sandisk) rank in the top 100 U.S. companies by valuation, and Vertiv sits at the 101st position, all ahead of household names like Blackstone, Salesforce, Pfizer, and Uber.

However, their growth trajectory depends almost entirely on sustained expansion of AI infrastructure investment. The trajectory is steep: spending is expected to climb from $650 billion（約100兆円） on a run-rate basis to $1.0 to $1.1 trillion（約180兆円） by 2027. Their high valuation multiples—ranging from 29 for GE Vernova to 88 for Seagate—reflect market expectations for strong continued profit growth. Any material slowdown in data center spending or capex cycles could trigger sharp declines, since the premium prices these companies now command for their products (Western Digital's offerings have risen as much as 50% since the start of last year; Sandisk faces supply shortages raising prices faster still) rest on severe supply constraints and unlimited demand.