Imagine pouring money into the hottest tech stock of the decade, watching it multiply your investment many times over—and then discovering a handful of quieter names in the same space did even better. That’s exactly what happened in 2025 for anyone chasing the artificial intelligence wave beyond the usual suspect.
Nvidia has been the poster child for AI success, turning early believers into millionaires and pushing its market value into the stratosphere. Yet while its shares kept climbing, a group of infrastructure players quietly—or not so quietly—delivered returns that left the chip giant in the dust. Some more than tripled, one even quadrupled. How did that happen? Simple: building the AI future takes a lot more than just fancy processors.
Data centers don’t run on GPUs alone. They need oceans of storage, lightning-fast networking, massive memory banks, and miles of optical connections. As the biggest tech companies poured hundreds of billions into new facilities, the suppliers of those essential pieces rode the same tsunami.
The Hidden Winners of the 2025 AI Build-Out
I’ve followed tech markets for years, and rarely have I seen such concentrated gains spread across an entire supply chain like this. It’s a reminder that sometimes the picks and shovels sell better than the gold itself. Here are the five standouts that turned heads this year.
Lumentum: Lighting Up the Connections
First up is a name many casual investors might not recognize right away. Lumentum makes the lasers, transceivers, and switches that power fiber-optic networks. You might remember them from older iPhone components, but these days their real growth engine is inside massive AI clusters.
Think about it: in a rack packed with GPUs, every card needs to talk to every other card at blistering speed. Scale that across thousands of racks, then across entire campuses, and you start to appreciate why optical components suddenly became priceless. The company reported sales jumping nearly 60% in their latest quarter, with the majority now tied directly to cloud and AI customers.
“Our growth is powered by AI demand spanning our laser chips and optical transceivers inside data centers, as well as the interconnected long-haul networks that link them.”
— Company CEO during recent earnings
The stock? Up roughly 375% for the year. That’s the kind of move that makes you sit up and take notice. Analysts expect strong growth to continue into next fiscal year before settling into a more moderate pace—perfectly reasonable after such a sprint.
What I find particularly interesting is how this shift caught traditional telecom-focused investors off guard. Many were still thinking carrier cycles when the real explosion came from hyperscalers linking their AI supercomputers.
Celestica: The Networking Powerhouse
Celestica might sound like a newcomer, but it’s been around since the 90s, originally spinning out of big blue. Today it’s become a go-to manufacturer for high-performance switches and networking gear that keeps enormous data centers humming.
Shares climbed more than 230% in 2025, and for good reason. The company has positioned itself squarely in front of two massive trends: the rise of liquid-cooled AI racks and the shift toward custom accelerators that are cheaper to run than general-purpose GPUs for certain workloads.
One major customer reportedly tapped them to build complete rack-scale solutions for next-generation AI training clusters, with volume production slated for 2026. When you hear stories like that, it’s easy to understand the excitement.
- Rising demand for custom ASICs over traditional GPUs in some applications
- Increasing adoption of liquid cooling for denser, hotter chips
- Long-term contracts with the largest cloud providers
Looking ahead, analysts actually project accelerating revenue growth over the next couple of years—something you don’t see often after such a strong run.
Seagate and Western Digital: Storage Gets Sexy Again
Remember when hard drives felt like yesterday’s technology? Not anymore. Both Seagate and Western Digital posted gains well over 200% this year, proving that spinning disks (and their solid-state cousins) still have a vital role in the AI era.
Here’s the thing: training giant models creates petabytes of data, and someone has to store it cost-effectively. While flash memory grabs headlines for speed, traditional hard drives remain unmatched for sheer capacity and dollars per terabyte. Hyperscalers buy them by the millions.
Seagate noted that roughly 80% of its business now flows to data center customers. Western Digital’s CEO put it bluntly: data is the new fuel for AI, and their drives provide the most economical tanks.
“There is no question that AI is reshaping hard drive demand by elevating the economic value of data and data storage.”
— Seagate leadership
Both companies saw healthy revenue increases in recent quarters, and the outlook calls for continued solid growth—though naturally tapering from 2025’s explosive levels. Perhaps the most telling sign: customers are locking in long-term volume and pricing commitments, something rarely seen in commodity hardware.
Micron: Memory Crunch Drives Massive Gains
Micron rounds out the list with a still-impressive 239% advance. As the only major U.S.-based DRAM and NAND producer, it’s perfectly placed to feed the insatiable appetite for high-bandwidth memory—the ultra-fast stuff glued directly to cutting-edge AI chips.
Demand has been so intense that production capacity for the newest generations sold out months in advance. Prices climbed accordingly, delivering record margins. The company even made the unusual move of exiting lower-margin consumer products to free up supply for data center clients.
Some analysts called the latest quarterly beat one of the biggest positive surprises in semiconductor history outside of, well, you know who. Next year’s revenue is expected to nearly double, though growth is projected to slow dramatically after that as new capacity comes online globally.
That slowdown raises perhaps the biggest question mark for all these names heading into 2026.
What Comes Next in 2026?
After a year like 2025, it’s natural to wonder whether the party can continue. On one hand, capital spending plans from the major cloud providers remain enormous. They’re not backing off the AI build-out anytime soon.
On the other, explosive growth rates rarely last forever. New manufacturing lines will eventually ease shortages in memory and optics. Competition could intensify. Efficiency improvements might reduce the need for certain components per training run.
Still, the underlying drivers look intact. AI models keep getting larger. Inference deployments are just beginning to scale. Edge computing and specialized workloads will create fresh demand pools.
- Watch capital expenditure guidance from the hyperscalers closely in January earnings season
- Monitor any signs of inventory building in the supply chain
- Pay attention to pricing trends in memory and storage contracts
- Look for evidence of sustained custom silicon adoption
In my view, the smartest approach might be expecting more moderate—but still healthy—gains rather than another year of triples and quadruples. These companies have moved from obscure to mainstream, and valuations now reflect lofty expectations.
That said, corrections in fast-moving tech sectors often create attractive re-entry points. If you’ve missed the 2025 ride, patience could pay off.
The AI infrastructure story clearly goes far beyond a single chip designer, no matter how dominant. This year’s surprise outperformers proved that the build-out touches dozens of specialized suppliers, each capturing their piece of a once-in-a-generation expansion.
Whether you’re already invested or just starting to look, understanding these supporting players gives a fuller picture of where the real money flowed in 2025—and where opportunities might still hide in the years ahead.
One thing feels certain: the data centers powering tomorrow’s AI won’t build themselves. And the companies supplying the essential pieces aren’t done growing yet.
