Data Center Rundown: September 2025

29 September 2025

Ah, September – that funny in-between month where summer fades, but the heat in the data center world doesn’t. While some folks were trading flip-flops for fall jackets, the infrastructure sector cranked up the intensity. AI-driven mega deals dominated headlines, sovereign-backed projects picked up speed, and we saw record-breaking momentum in both capital and construction.

From San Antonio to Wisconsin and Essex to Atlanta, the expansion of hyperscale and AI infrastructure this month was relentless. If August made it clear that AI is fueling global infrastructure, September doubled down – with some serious dollar signs attached.

Here are the biggest headlines you may have missed this month:

OpenAI, Oracle & SoftBank announce five new Stargate AI data centers

The Stargate initiative, a $500 billion AI infrastructure moonshot, added five more US locations this month, including new projects in Ohio, Texas, and the Midwest. The total initiative now aims to surpass 7 GW of capacity, supporting OpenAI’s next-gen models and cloud scale.

UK and US sign $42bn tech pact as part of broader AI and data center investment wave

Timed with President Trump’s visit to London, the UK and US governments announced a sweeping $42 billion bilateral tech and AI infrastructure pact. The deal includes investment commitments from major US players – including Microsoft, Nvidia, CoreWeave, OpenAI, and Scale AI – aimed at scaling cloud, AI, and data center capacity across the UK. While many of the individual deals (like Microsoft’s $6bn Nscale lease, mentioned below) were already in motion, the pact formalizes the UK’s role as a strategic destination for sovereign AI infrastructure.

CoreWeave expands OpenAI contract by $6.5B, total value now $22.4B

The GPU cloud giant added another $6.5 billion in AI infrastructure services under its agreement with OpenAI – bringing total contract value to an eye-watering $22.4 billion. CoreWeave says it’s doubling down on 2026 capacity as demand for Blackwell-class chips spikes.

US data center construction hits record $40B run rate

A Bank of America Institute report shows construction spending on data centers reached a record-setting $40 billion annualized pace in June, reflecting a ~30% YoY increase driven by AI-scale builds. The surge is broadly driven by hyperscalers (Microsoft, Amazon, Google/Alphabet) scaling AI workloads, expanding clouds, and building new compute campuses.

OpenAI and Nvidia formally announce ‘Stargate UK’ AI infrastructure buildout

OpenAI and Nvidia have officially launched "Stargate UK" - a multi-billion-pound AI infrastructure initiative in partnership with data center operator Nscale. The project will deliver tens of thousands of Nvidia GPUs across multiple UK sites, starting with Nscale’s Essex campus, which will host 23,000+ Blackwell chips. The move marks a major step in Britain's push to become a sovereign AI compute hub and signals OpenAI’s expanding infrastructure strategy beyond the US.

Microsoft joins the party with $6bn AI compute deal from Nscale

Hot on the heels of OpenAI and Nvidia’s Stargate UK reveal, Microsoft has inked its own massive agreement with Nscale – a $6 billion deal to lease high-performance GPU compute across the company’s UK data centers. The multi-year arrangement gives Microsoft access to tens of thousands of Nvidia H100 and Blackwell chips, bolstering its Azure AI infrastructure without the long wait for new builds.

Nvidia‑backed Nscale raises $1.1B

More from Nscale as it closed a $1.1 billion funding round led by Aker (Norway), valuing it at ~$3 billion. Notably, Nvidia is not only supplying up to 300,000 AI chips but also investing $500 million into the venture.

Nscale aims to build sovereign, privacy-focused AI compute infrastructure with an emphasis on Europe, the US, and the Middle East, offering an alternative to US hyperscalers.

EdgeConneX and Lambda team up for dual-city AI data center build

In a strategic push to meet AI latency and redundancy demands, EdgeConneX and Lambda have announced a new dual-city infrastructure project spanning Chicago and Atlanta. The two sites will operate as mirrored AI hubs, designed for rapid compute scaling and high-bandwidth interconnection.

Microsoft unveils “Fairwater,” a giant new AI campus

Microsoft announced a new 315-acre AI data center campus in Pleasantville, Wisconsin, claiming it will host “hundreds of thousands” of Nvidia GB200/GB300 GPUs and extensive fiber capacity (enough to circle the Earth 4.5 times). Notably, the design emphasizes sustainability: closed-loop water cooling and zero‑waste water systems are part of the plan.

Vantage expands in Texas

Vantage Data Centers announced a new $276.9m, 432,800 sq ft facility in San Antonio’s far west side, with 96 MW of capacity planned.

Construction is slated to start October 2025, with completion expected in 2027.

Elliott eyes sale of UK’s Ark Data Centres

In the UK, hedge fund Elliott is exploring strategic options, possibly selling Ark Data Centres in a deal that could exceed £3 billion.

Power infrastructure push & controversy in Louisiana

Meta’s planned $10 billion data center in Holly Ridge, Louisiana, is driving a $3 billion power upgrade (gas plants & transmission lines) funded in part by utility Entergy. While Meta commits to covering some costs over 15 years, critics warn public exposure risks if Meta exits or doesn't renew.

Local pushback, rezoning battles continue

In Indianapolis, Google withdrew a contentious rezoning proposal for a 500-acre data center campus after sustained opposition from residents citing concerns about energy, water use, and quality of life.

Hydrogen + off‑grid AI deployment

One of the more futuristic storylines: Lambda (with ECL and Supermicro) launched production‑grade Nvidia GB300/NVL72 AI systems in an off-grid, hydrogen-powered data center campus (“MV1”) in Mountain View, California.

Running entirely on hydrogen fuel cells and with zero external water use, this marks a provocative proof-of-concept for ultra-low-emission, modular AI compute.

That’s a wrap for September!

We saw deals that redefined scale, partnerships that rewrote borders, and infrastructure designed to meet the moment. If 2025 continues at this pace, next year’s data center map will look radically different.

Don’t miss next month’s edition – October is already shaping up to deliver more big moves, big builds, and even bigger ideas.

Until then, keep those GPUs cool and your fiber lit!

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