SoftBank's $25 Billion Arm Loan Funds AI Bets That Haven't Paid Yet

Bloomberg reported on the morning of 18 September that SoftBank has raised its margin loan backed by Arm Holdings shares by another $5 billion, to $25 billion, the third upsizing since 2023 ¹. Lenders offered about $7 billion of demand against an initial ask of $3 billion to $5 billion ¹; if the cycle turns, the people on the hook are SoftBank's creditors and Arm's minority shareholders.

The facility began at $8.5 billion in 2023, rose to $13.5 billion in 2024 and $20 billion in 2025, with $20 billion already drawn as of December, so this raise is headroom, not decoration ¹. It is secured by 769 million Arm shares, 72% of the company, of the nearly 90% SoftBank owns ¹. Arm is up 142% this year ¹.

Public AI collateral is cheap; private needs the balance sheet

Strip the story down: Masayoshi Son is borrowing against the one AI asset in his portfolio with a public price to fund the ones without. Public collateral is cheap: the Arm facility costs roughly 225 basis points over SOFR, plus a 25-basis-point credit adjustment ¹. Private collateral gets the balance sheet.

When SoftBank sought a loan backed solely by its OpenAI stake↗, banks pushed back, because they would have had no claim on SoftBank beyond shares they could not easily value or sell; SoftBank had to add a corporate guarantee ². The pricing tells you which AI asset lenders actually trust.

The machine this cash feeds has no revenue yet

Follow the cash. SoftBank has committed $64.6 billion to OpenAI ³, and this week repaid the entire $25.9 billion balance of the $40 billion one-year bridge behind that investment ¹. Last week it sealed an $11.87 billion two-year loan↗ from about 20 banks ⁷; in August, $10 billion against the OpenAI stake ⁴. Apollo is now in talks to lift a Vision Fund 2 loan from $5.4 billion to $9 billion ³.

Then SB Energy: 8.8 gigawatts of US data centers estimated to need $174 billion of capex ¹, and an IPO filing↗ showing a $3.21 billion first-half net loss on $138.7 million of revenue, with no data center operational ⁸.

Creditors and Arm's minority owners hold the tail

Lenders priced this willingly and bid past the ask ¹, and Nvidia has agreed to guarantee up to $105 billion↗ of OpenAI's 20-year lease on the Ohio campus, whose first 800 megawatts arrive in 2028 ⁵. But the OpenAI loan states the mechanism: SoftBank must post cash or repay early if OpenAI's preferred shares drop sharply ⁴.

Every margin loan ties borrowing capacity to collateral value; capacity is largest exactly when it is needed least. Credit-default swaps on SoftBank hit a three-year high this week ³, and S&P downgraded the group in March, saying the OpenAI investment would "further reduce SoftBank Group's financial capacity" ⁶. The Arm facility's covenants are not public.

Arm's share price is now SoftBank's funding gauge

The binding constraint is not ambition or chips; it is cash that arrives before revenue. Debt buys time: only OpenAI's revenue, the IPO now pushed to 2027 ³, or SB Energy's first megawatts turn collateral marks into money.

Until then, watch Arm's price: it sets SoftBank's borrowing capacity and could support a fourth upsizing ¹. The asset that already worked now carries the assets that might: the AI sentiment gauge and SoftBank's funding gauge are the same dial.