Why has AT&S Austria Technologie & Systemtechnik increased in price so much in the past year?

As of September 27, 2026 · Vienna-listed AT&S · All financial figures in euros unless stated otherwise

AT&S rose from €22 to €203.50 in a year—an 825% gain. What changed enough to make the Austrian circuit-board and semiconductor-substrate manufacturer worth more than nine times its starting share price? The comparison uses Vienna closes on September 26, 2025 and September 25, 2026, the last trading session before this note. [1] [2]

Our view is that investors reassessed the value of AT&S’s expensive new factories. Capacity that had consumed cash and depressed earnings increasingly looked like valuable infrastructure for AI chips. Named customers, sharply higher guidance and improving production economics gave that reassessment substance. [3] [4] [5]

But the scale of the rally requires another explanation: investors also began paying much more for each euro of expected earnings. On a consistent calculation, enterprise value rose from approximately 3.8 times to 9.6 times the contemporaneous midpoint of management’s outlook for the same fiscal year, FY2026/27. That is the number that carries this story. Better earnings explain part of the move; greater confidence in the duration and value of future growth explains the much larger revaluation. [6] [3] [7] [8] [1] [2] [9]

The rally anticipated the orders, then accelerated on confirmation

The price path rules out a neat explanation built around one announcement. AT&S had already reached €141 by May 29, before its largest disclosed guidance upgrade. Roughly two-thirds of the eventual €181.50 net gain per share had accumulated by then. The stock subsequently fell 38% between June and July month ends before recovering. This was a sustained reassessment punctuated by sharp reversals. [10]

The price rose well before June’s guidance upgrade, then suffered a substantial July reversal. Source: Vienna Stock Exchange. [10]

A powerful sector backdrop helped. The Philadelphia Semiconductor Index approximately doubled over the matched dates, measured in its US-market currency. Closer to AT&S’s business, Unimicron reported AI-data-center applications rising from 47% of sales in the second quarter of 2025 to 61% a year later. The demand shift extended beyond one supplier. [11] [12]

Yet the company-specific evidence is stronger than a generic semiconductor rally. The decisive change was that AT&S could connect AI demand to identified customers, an expanded investment program and a much larger earnings outlook. The earlier price rise shows investors were anticipating improvement; the customer announcements made that improvement more tangible.

AMD and Marvell made the AI opportunity concrete

AT&S makes advanced IC substrates used in semiconductor packaging. For a chip company, securing the manufacturing capability behind increasingly complex products is part of securing its own ability to grow. For AT&S, customer commitments improve confidence that costly production capacity will find buyers. The June expansion announcement brought those interests together at Kulim, Malaysia. [3]

On June 13, AT&S said it had agreed key terms with AMD and another leading technology company to expand high-end substrate production for AI and high-performance computing. The plan covered additional capacity in the existing plant and the previously unused building of the second plant. Management described €1.5 billion–€2 billion of investment supported and financed by long-term customer commitments, subject at that point to final negotiation and execution. [3]

The associated guidance change was substantial. Expected currency-adjusted revenue growth for FY2026/27 increased from 30–35% to 45–55%, while the EBITDA-margin range increased from 25–29% to 32–37%. Higher sales and higher margins compound: more revenue passes through a more profitable manufacturing operation. [3]

June’s revision increased the implied EBITDA midpoint by approximately 45%, while also sharply increasing investment requirements. Source: AT&S; our calculations. [3] [13]

Method: apply each growth and margin midpoint to FY2025/26 revenue of €1.791 billion, holding exchange rates unchanged; combine range endpoints for the latest EBITDA range.

The latest guidance implies approximately €831 million–€1.027 billion of EBITDA, with a midpoint of €927 million. The preceding outlook implied a midpoint of €641 million on the same calculation. A roughly 45% earnings upgrade helps explain why the shares jumped 36.2% in the first trading session after the announcement, from €154.20 to €210. [13] [3] [10]

September brought a name to the second customer: Marvell. Its expanded collaboration with AT&S confirmed the relationship behind June’s capacity plan. The shares rose 10.4% on September 22. This was stronger confirmation of an existing expansion, with Marvell identifying the supply-chain reason for committing to it. [4] [2]

Marvell’s chief supply-chain officer, Vinay Krishna, said that securing “the manufacturing capacity and advanced technology capabilities required to support our customers remains a critical priority.” That is the buyer’s side of AT&S’s opportunity: customers value assured access to manufacturing capability as their data-center businesses expand. AT&S gains confidence to invest, while customers secure capacity. The eventual return to shareholders still depends on pricing, production yields and the cash terms of those commitments. [4]

The operating recovery is concentrated where the AI thesis needs it

Customer commitments explain why expectations changed. The operating results explain why we take that change seriously.

In April–June 2026, the first quarter of FY2026/27, revenue increased 37.6% to €548.7 million. EBITDA increased 133.7% to €165 million, lifting the margin from 17.7% to 30.1%. Net profit reached approximately €41 million, compared with a €56 million loss a year earlier. Rising sales were producing a disproportionately large improvement in earnings. [14] [15]

The segment split is more revealing than the consolidated growth rate. Microelectronics added €162.7 million of external revenue, while Electronics lost €12.9 million. The substrate business supplied more than the entire group’s €149.8 million sales increase. Our view is that this concentrated recovery supports the investment thesis much more convincingly than a broad improvement across unrelated end markets would. [14]

Microelectronics supplied more than the group’s entire quarterly revenue increase. Source: AT&S quarterly report; changes calculated from external revenue. [14]

Factory economics help explain the margin recovery. A new production site incurs costs before it contributes enough sales to absorb them. As production ramps, those expenses can fall while revenue rises. At Kulim and Hinterberg, annual start-up costs declined from €123.2 million to €17 million in FY2025/26—a €106.2 million reduction. Microelectronics EBITDA increased €151.8 million over the same year. The reduction in start-up costs was about 70% of that increase in scale, although the segment’s full earnings bridge includes other moving parts. [5] [16]

Management also reported €170 million of cost savings in FY2025/26 and targeted another €110 million for FY2026/27. These program figures overlap with the wider operating improvement, so we treat them as evidence of the mechanism rather than separate amounts to add to profit growth. [17]

Annual headline EBITDA needs one adjustment to see the recovery clearly. FY2024/25’s €605.7 million included a €324.8 million gain from the Ansan disposal. Removing that identified gain leaves €280.9 million; the subsequent year’s €418 million was approximately 49% higher. The improving business was obscured by an unusually flattering prior-year reported figure. [18]

We therefore give the operating turnaround substantial weight. The evidence includes higher substrate sales, lower factory start-up costs and a return to quarterly net profit. It also sets the boundary of the claim: Microelectronics encompasses more than AI, so its growth cannot be translated into a precise AI revenue share. [14] [5]

A higher earnings multiple explains the extraordinary scale

A credible turnaround can produce a very large equity return when the starting valuation is depressed. Equity holders own the value left after financial claims. Improved earnings raise that value; reduced perceived financing risk can also persuade investors to pay a higher multiple for it. Both mechanisms matter here.

To separate them, we compare the same fiscal year’s expected EBITDA at both share-price dates. The outlook available in July 2025 implied a €585 million midpoint for FY2026/27: €2.25 billion of revenue multiplied by a 26% margin. The latest guidance implies €927 million at unchanged exchange rates, an increase of approximately 58%. Meanwhile, the equity market value increased from about €0.85 billion to €7.91 billion, using 38.85 million issued shares throughout. [6] [3] [13] [9] [1] [2]

Expected EBITDA increased substantially, but the multiple investors paid increased much more. Sources: AT&S, Vienna Stock Exchange and Fiscal.ai; our calculations. [6] [3] [7] [8] [9] [1] [2]

Method: 38.85 million issued shares at both dates; June quarter-end net debt paired with September prices. Enterprise value adds issuer-defined net debt, including leases, to equity value. EBITDA uses contemporaneous management-outlook midpoints for FY2026/27. Future conversion dilution is excluded.

The arithmetic is instructive. Of the €7.05 billion increase in equity value, approximately €1.31 billion comes from applying the old multiple to the increase in expected EBITDA. Another €432 million comes from lower reported net debt. The remaining €5.31 billion—about 75% of the increase—is associated with the higher multiple in this sequential bridge. [6] [3] [13] [7] [8] [9] [1] [2]

That bridge is an accounting decomposition whose allocation depends on the order of calculation. Economically, the higher multiple can reflect a longer growth runway, better confidence in customers, lower financing risk and the passage of time toward the forecast year. We are skeptical that operating improvement alone explains the share-price move, because the earnings upgrade is so much smaller than the equity revaluation.

The strongest argument against emphasizing the multiple is that a single year’s EBITDA understates a multi-year AI opportunity. We give that argument substantial weight. Customer-supported capacity and rapidly growing substrate sales can justify a higher valuation than a year earlier. The evidence supports a more valuable business; it leaves the return available at today’s price dependent on how much of that future growth becomes cash. [3] [14]

Financing risk eased, while the cash burden remained

Cash generation has improved. Annual operating free cash flow moved from approximately minus €489 million in FY2024/25 to plus €235 million in FY2025/26. Stronger operating cash flow helped, as did net capital expenditure falling from €414.8 million to €178.3 million. Investors had evidence that AT&S could move beyond its heaviest period of cash consumption. [5] [18]

The latest net-debt improvement has a different composition. AT&S issued a €400 million deeply subordinated perpetual convertible hybrid in June 2026, classified as equity. Between June 2025 and June 2026, issuer-defined net debt fell approximately €432 million. Adding the carrying value of hybrids to both snapshots reduces the decline in combined claims to approximately €35 million. Hybrids have different legal rights from conventional loans, but this sensitivity shows how much of the reported improvement came from financing. [19] [7] [8]

Our view is that financing confidence improved, while cash-earned deleveraging was much smaller than the headline net-debt movement suggests. The valuation conclusion survives the accounting choice: including hybrids in enterprise value raises the forward multiples to approximately 4.4 times and 10.4 times, preserving the large revaluation. [7] [8] [6] [3] [13] [9] [1] [2]

The renewed expansion makes cash conversion decisive. Planned FY2026/27 capital expenditure increased from roughly €400 million to €1 billion–€1.2 billion alongside the June guidance upgrade. First-quarter operating free cash flow was only €5.1 million despite €165 million of EBITDA. The investment program can create value, but the customer funding schedule and production ramp determine how much cash AT&S must supply along the way. [3] [8]