IREN hands Microsoft its first 50MW, and the $9.7B contract starts having to be true

IREN has delivered the first 50MW block of its Horizon build to Microsoft, completing the opening milestone of a five-year, $9.7 billion cloud services contract signed in November 2025 ^[1][2]. It matters because the contract does not pay on announcement: Microsoft has five days to validate each GPU deployment against mutually accepted standards, and only when acceptance completes does the service period begin and monthly billing start ^[3].

Horizon 1 sits at IREN's Childress, Texas campus: 50MW, direct chip-level cooling, Nvidia GB300 systems ^[4]. It is the first of four such blocks the company says it will complete by 2026, for 200MW in total ^[5], which puts a quarter of the contracted capacity in place ^[1]. Nvidia awarded the site Exemplar Cloud status, a designation for cloud providers meeting its performance and reliability standards for AI workloads ^[6]. Co-founder and co-CEO Daniel Roberts said the delivery "underscores the power of our vertically integrated business model and our ability to deliver on complex AI infrastructure projects with speed and scale" ^[7]. That sentence tells you nothing about whether the GPUs passed validation, which is the only part investors should currently care about.

The arithmetic is unusually clean. IREN puts annualised revenue at about $1.94 billion once all four Horizon sites are online ^[8], which is precisely $9.7 billion divided by five years ^[2]. Straight-lined, each 50MW block carries roughly $485 million a year, or about $9.7 million per megawatt per year ^[3]. Microsoft is also required to pay 20% of total contract value upfront across four tranches ^[9], implying roughly $1.94 billion of prepayment ^[4] arriving ahead of the service revenue it corresponds to.

What the Microsoft deal does not do is get IREN to its own target. Management is guiding to more than $4 billion of annualised AI Cloud run-rate revenue by the end of the year, with over 85% of revenue contracted ^[10]. At full run rate, Microsoft supplies under half of that, leaving more than $2 billion to come from counterparties not named in this material ^[5].

The capital side is where the disclosure gets loose. The expansion is estimated to need about $5.8 billion of GPUs and related hardware bought from Dell, with funding secured for all but a minority ^[11]. That includes $3.65 billion of secured debt arranged in June, guaranteed by the Microsoft deal and rated A by Fitch and A(low) by DBRS, which Cryptopolitan, citing The Block, describes as covering 96% of the $5.81 billion GPU spend ^[12]. As stated, $3.65 billion is 63% of $5.81 billion ^[6], so the 96% figure must be picking up other sources or is imprecise. Read the filings before repeating it.

The legacy business explains the urgency. IREN listed on Nasdaq in 2021 as a bitcoin miner ^[13], and the source reports mining revenue of $511.5 million against $58.3 million of AI Cloud revenue for a first-nine-month period in 2022, roughly nine to one ^[14][7]. The company now plans 480MW of AI cloud capacity in 2026 and 1.2GW in 2027 while exiting mining ^[15]. Cryptopolitan cites bitcoin near $63,500 in mid-August, less than half the October 2025 peak, without specifying the year of that mid-August reading ^[16], so treat the comparison as directional rather than dated.

Watch for confirmation that Horizon 1 cleared the five-day validation and a stated service commencement date ^[3], the delivery dates for Horizons 2 through 4 against the 2026 deadline ^[5], the first month of Microsoft billing appearing in reported revenue, and the non-Microsoft contracts required to bridge from $1.94 billion to $4 billion ^[5].