European AI infrastructure companies emerged as some of 2026's biggest stock-market winners, with shares climbing hundreds of percent as spending on AI data centres accelerated.

Ten European companies supplying critical AI hardware—including optical networking, photonics, chip testing, and server cooling—delivered the strongest year-to-date gains in 2026. The top performer, 2CRSi, surged 410.03%; AT&S rose 366.46%; AIXTRON gained 234.70%; and Raspberry Pi Holdings climbed 198.63%.

These companies manufacture infrastructure layers essential to AI data centres: Nokia makes optical-transport and IP-networking gear; ams-OSRAM develops sensors and optical technologies for photonics; Technoprobe produces probe cards (precision interfaces that test chips before they ship); and 2CRSi designs energy-efficient servers with advanced cooling systems for AI workloads.

Several companies remain loss-making or trade on expectations of future AI demand rather than present revenues. Investors are betting that AI infrastructure spending will continue to expand rapidly, though some analysts—such as Berenberg on AIXTRON—have warned that stock prices may have outrun current earnings.