Spanish builder ACS Group said its data center construction backlog reached approximately €26 billion at the end of September, up 94% year on year, in its results release for the first nine months of 2026. That is about 23% of a record group backlog of €110,994 million, by our arithmetic.
Attributable net profit rose 20.5% to €789 million, and data center projects took €644 million of the €2,172 million ACS invested in the period, about 30% by our arithmetic. ACS said it would present the results and its strategic vision at a Capital Markets Day on 12 November.
Business Pill · Backlog
An evergreen Business Engineer explainer on backlog: contracted work not yet delivered. It teaches the general idea only and does not discuss ACS.
The key insight: As we read the release, data centers are now the largest single driver of ACS’s order book: a backlog of about €26 billion, about 23% of the group total by our arithmetic, growing at 94% while the whole backlog grew 24%.
Sales reached €41,262 million, up 14% FX-adjusted, and EBITDA rose 13% to €2,506 million, ACS said. New orders were €56,228 million, up 28.2%, with a book-to-bill ratio of 1.4x over the last twelve months.
The release says growth was “driven particularly by next-generation infrastructure markets, notably data center construction”. Backlog in Energy, Water and Industry (including Nuclear) and Critical Minerals rose 67.5% combined.
ACS Group investments in the first nine months of 2026, from its results release: €727 million for the remaining Thiess minority stake, €644 million in data center projects, €524 million to raise its HOCHTIEF stake and €276 million in other investments, €2,172 million in all. The data center share, about 30%, is our arithmetic.
Turner Carries the Data Center Work
Turner, ACS’s US builder, grew sales 23.8% FX-adjusted, “driven primarily by data centers”. Its EBITDA rose 41.0% to €905 million and profit before tax rose 43% to €891 million, with a margin of 4.0%.
Turner’s backlog reached a record €48,947 million, up 42.4%, and its data center backlog rose 84% year on year, according to the release. Turner alone holds about 44% of the group backlog, by our arithmetic. HOCHTIEF, Turner’s parent within the group, said in its own release that its AI, digital and technology backlog rose more than 90%.
Where the Money Went
Of the €2,172 million invested in the nine months, €727 million bought the remaining minority stake in Thiess, €644 million went to data center projects, €524 million raised the stake in HOCHTIEF and €276 million went to other infrastructure and acquisitions. Divestments of €598 million included the Coravel transaction, the data center joint venture set up this year with GIP BlackRock.
Net debt ended September at €908 million, €1,319 million lower than a year earlier. The data center backlog of about €26 billion implies about €13.4 billion a year earlier, by our arithmetic from the 94% rise. Our earlier coverage tracked other suppliers’ data center order books, such as Generac’s data center backlog and Caterpillar’s power generation sales.
The Structural Read
As we read the investment list, ACS is putting its own capital into data center projects as well as building them for clients: €644 million in nine months, about 30% of its investments by our arithmetic.
As we read the Turner figures, the US builder is where most of this lands: its data center backlog rose 84%, and its profit before tax rose 43% with a 4.0% margin.
ACS Group 9M 2026 results release
“Growth was driven particularly by next-generation infrastructure markets, notably data center construction, where backlog reached approximately €26 billion, up 94% year-on-year.”
Three Implications
FOR ACS New orders of €56,228 million, up 28.2%, gave a book-to-bill ratio of 1.4x over twelve months, the release says.
FOR TURNER Its backlog reached a record €48,947 million, about 44% of the group total by our arithmetic.
FOR THE BUILD-OUT The release says the Coravel data center joint venture with GIP BlackRock was set up this year and was among the divestments.
The framework says: “the capex race is no longer a corporate spending cycle. It is a sovereign-scale financing problem dressed in tech-company clothing”.
As we read it, a builder’s order book is where that spending becomes contracted work, and ACS’s €26 billion data center backlog is one measure of it. The framework does not discuss ACS.
Year-on-year backlog growth at the end of September 2026, from ACS Group’s nine-month release: data centers 94%, Turner data centers 84%, Energy, Water and Industry (including Nuclear) and Critical Minerals combined 67.5%, Turner overall 42.4% and the group 24%.
What Is Not Established
The nine-month release does not set out 2030 targets. ACS said it would present its strategic vision at the Capital Markets Day; we did not read the presentation or the reports on it for this piece. The release gives the data center backlog as an approximate figure and does not name the customers behind it. We did not contact ACS.
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ACS says its data center construction backlog reached approximately €26 billion at the end of September 2026, up 94% year on year, out of a record €110,994 million group backlog. Data center projects took €644 million of its €2,172 million nine-month investments, and Turner’s data center backlog rose 84%.
A note on sourcing. All results figures come from ACS Group’s release on its first nine months of 2026, which we read in full on its press room, and the HOCHTIEF figure from HOCHTIEF’s own nine-month release. The Capital Markets Day date comes from ACS’s investor pages. Shares and the implied year-earlier backlog are our arithmetic. ACS was not contacted for this piece.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
