IREN Closes $3.65 Billion Facility for Microsoft AI Infrastructure in Largest Dedicated Build-Out

IREN, the digital infrastructure operator formerly known as Iris Energy, closed a $3.65 billion project financing facility dedicated to building and operating artificial intelligence compute infrastructure for Microsoft. The facility represents the largest single-purpose AI infrastructure funding round disclosed this year and arrives as hyperscalers confront the capital intensity of deploying frontier models at enterprise scale.

The financing is structured as a non-recourse project facility, isolating Microsoft's infrastructure commitment from IREN's existing bitcoin mining operations. Terms were not disclosed, but the structure suggests Microsoft retains long-term offtake agreements while IREN holds operational risk and upside from utilization above contracted minimums. The facility closed in late April, with construction expected to begin in Q2 2025 across multiple sites in North America. IREN's equity contribution appears minimal — the company's total market capitalization sits near $2.1 billion as of this writing — indicating the facility is largely debt-financed with revenue certainty provided by Microsoft's commitments.

This matters because it signals a financing model hyperscalers increasingly prefer: moving capital-intensive infrastructure off their balance sheets while locking in capacity through long-duration contracts. Microsoft has committed over $80 billion to AI and cloud infrastructure spending in fiscal 2025, but that figure includes land, building shells, and networking — not the full cost of compute deployment at the pace demand requires. By engaging specialist operators like IREN and structuring project finance around contracted cash flows, Microsoft converts a lumpy capex cycle into predictable opex while preserving balance sheet capacity for acquisitions, buybacks, and model development.

The financing also reshapes IREN's business profile. The company generated approximately $214 million in revenue over the trailing twelve months, nearly all from bitcoin mining. A $3.65 billion facility implies annual debt service in the range of $250-$350 million depending on tenor and rate, suggesting Microsoft's contracted payments will dwarf IREN's legacy operations. The company is effectively pivoting from commodity exposure in proof-of-work networks to becoming a captive infrastructure provider for a single hyperscaler — a higher-certainty, lower-volatility business model that trades merchant upside for contracted revenue.

Allocators should watch for two follow-on developments. First, whether Microsoft replicates this structure with other operators, potentially including Core Scientific or Applied Digital, both of which have signaled interest in pivoting capacity toward AI workloads. Second, whether other hyperscalers — notably Amazon Web Services and Google Cloud — adopt similar off-balance-sheet financing strategies as AI infrastructure spending accelerates beyond internal capital allocation comfort zones. Both developments would likely surface within the next two to three quarters as Q2 and Q3 earnings calls clarify capital deployment priorities.

IREN's equity has traded up approximately 34% since the financing was first rumored in early April, but the real signal is in the debt markets: project finance at this scale requires syndication across infrastructure funds, sovereign wealth vehicles, and pension allocators who typically demand visibility into contracted cash flows extending ten to fifteen years. Microsoft provided that visibility. The hyperscaler now has a replicable template.