IREN’s $3.65B Financing: The Customer Is the Collateral

$IREN secured 96% of the $5.81bn GPU capex for its Microsoft contract at a low single-digit all-in financing cost. This was enabled by by the Microsoft lease itself and carries investment-grade credit rating.

Management says it “essentially got the GPUs for next to nothing” and quotes an all-in cost of 3.31%, though I’d read that number with some caution. It treats Microsoft’s prepayment as free money, when a prepayment is really an advance IREN repays later in compute. The honest borrowing cost is the 6.00%. Which raises the real question: how does a company like this borrow billions at 6%, when the sector spent years shut out of the debt markets entirely? The answer is the credit rating.

The facility was rated A by Fitch and A (low) by DBRS. A credit rating is simply a grade for how likely a borrower is to repay, and each agency uses its own labels. Here’s how the “A” band lines up:

Anything at BBB (Upper B) or above is investment grade. Below that line, debt is considered high-yield, or speculative grade. The A band sits well inside the investment-grade zone.

Now the part that matters. IREN, on its own as a growth company, is nowhere near an A. But the lenders aren’t really betting on IREN. They’re betting on Microsoft who holds AAA long-term credit rating from the major rating agencies. That is about as safe as a borrower gets. Because the debt is secured by Microsoft’s contracted payments, the agencies looked past IREN and the fast-aging chips and graded the strength of Microsoft’s promise instead. Strip it down, and IREN borrowed against Microsoft’s balance sheet.

That single notch below perfect, an A instead of Microsoft’s AAA, is the agencies’ price for what Microsoft’s promise doesn’t cover: GPUs that lose value quickly, and the chance IREN stumbles on delivery.

An investment-grade stamp doesn’t just look good. It decides who is allowed to lend. The market IREN tapped is where insurers and pension funds put their money. They hold huge long-term pools against future claims and payouts, they want steady low-risk income, and the rules largely forbid them from holding anything below investment grade.

Clear the investment-grade bar and you open that door, to the deepest and cheapest capital available. Miss it, and you’re left with private-credit funds charging nearly double digits, which is where the sector sat a year ago. The rating is the door. Microsoft’s credit is the key.

CoreWeave got investment-grade GPU financing in March, closing an $8.5BGPU-backed deal at a nearly identical rating.

IREN’s rating is a notch higher, and it owns its data centers while CoreWeave mostly rents. You’d expect that to translate into cheaper money. It didn’t. Both priced at almost the same spread, around SOFR plus 2.13% (SOFR is the going benchmark rate). The rating edge and the owned buildings were nice to have. What actually got both deals done was the same thing: a customer creditworthy enough to rate. That’s the gate. Everything else is a tiebreaker.

So what should an IREN shareholder take away from all this?

The upside is real. Funding a $5.81B buildout with debt and a customer’s cash, rather than printing new shares, is the reverse of the sector’s usual playbook. No dilution, and capital cheaper than the company could find elsewhere.