Substrate maker AT&S lifts Austria to top eurozone market
A little-known Austrian semiconductor supplier has surged 459% this year, single-handedly turning a traditionally bank-heavy national index into the eurozone’s best-performing equity market of 2026.
Austria’s ATX index has gained 21.3% since January, making it the top-performing major equity market in the eurozone this year. The benchmark has easily outpaced the Euro Stoxx 50, which is up just 8.2%, while Germany’s DAX and France’s CAC 40 have managed gains of only 1.6% and 2.3% respectively. The entire outperformance rests on a single company.
AT&S, a semiconductor supplier based in the Styrian town of Leoben, has seen its shares climb 459% to €174, pushing its market capitalisation from €1.25 billion to roughly €7 billion. The rally has outpaced familiar names in the artificial intelligence boom like AMD, Intel and Micron. Yet AT&S remains obscure outside the industry because it manufactures a component that end consumers never see.
The company produces integrated circuit substrates, the advanced platforms that sit beneath modern AI processors. These substrates provide structural support and house the thousands of microscopic electrical connections required to transfer data and power. Manufacturing them requires extraordinary precision across multiple ultra-thin layers, leaving only a handful of global competitors, primarily Japan’s Ibiden and Shinko Electric. AT&S stands as the only major European manufacturer in this critical segment, which is forecast to reach $11.1 billion globally this year.
Investor confidence is backed by recently strengthened finances. In its 2025/26 financial year, AT&S posted revenue of €1.8 billion, up 21% at constant exchange rates. Excluding the sale of a South Korean plant, EBITDA jumped 50% to €418 million, and free cash flow swung to a positive €236 million.
"2025/26 was a strong and pivotal financial year for AT&S," chief executive Michael Mertin said when the company reported annual results on 21 May.
A single stock reshapes a national index
Enthusiasm accelerated on 13 June when AT&S announced agreements with AMD and another major customer, reported to be Intel, to expand capacity in Malaysia and China. The planned investment of €1.5 billion to €2 billion matched the company's entire market value at the start of the year.
The surge has altered the composition of Austrian investment funds, with AT&S now the fourth-largest holding in the iShares MSCI Austria ETF at 5.9%. Financial stocks like Erste Group and BAWAG still dominate roughly half the portfolio. But the AT&S rally offers a broader lesson for European investors. While the continent largely lacks the vast consumer-facing tech ecosystems of the US or Asia, controlling highly specialised bottleneck components in the AI supply chain can still generate outsized returns—and entirely redefine a national market.
