SoftBank expands Arm-backed margin loan to $25 billion as AI bets surge

SoftBank Group has expanded the margin loan secured against its stake in ARM to $25 billion, a $5 billion increase on the prior $20 billion facility, according to reporting on September 18, 2026. The figure is consistent across every outlet carrying the story, including the Bloomberg wire copy that most of them are running.

The structure is worth naming plainly, because a margin loan is not ordinary corporate debt. SoftBank is borrowing against shares it already owns rather than issuing new equity or unsecured paper, which preserves its stake and avoids dilution but ties the facility's headroom to Arm's share price. A sharp drawdown in Arm would tighten that headroom precisely when SoftBank would least want it to.

The proceeds sit behind SoftBank's AI commitments, the largest of which is its $60 billion commitment to OpenAI. One outlet reports that part of the increase repays a short-term OpenAI-related loan, though that detail appears in a single source and is not corroborated elsewhere. The number of Arm shares pledged against the enlarged facility has not been disclosed in any of the September 18 reporting.

What to watch is leverage against a single holding. The questions that decide whether this is prudent financing or concentrated risk are how much of SoftBank's Arm position is now encumbered, what the facility's loan-to-value triggers are, and whether the capital converts into deployed AI investment rather than refinancing of existing obligations.