SoftBank has built a position in OpenAI worth tens of billions of dollars using a method that works well while valuations rise and poorly if they do not.
The pattern is consistent: sell assets, borrow against what remains, buy more OpenAI stock, then borrow against the higher marked value of that holding.
Masayoshi Son sold SoftBank's entire Nvidia stake for $5.83 billion and $12.73 billion of T-Mobile shares between June and December 2025, then arranged a $40 billion bridge loan.This week the group secured a $10 billion margin loan backed by its OpenAI stake, agreed with Goldman Sachs Bank USA, JPMorgan Chase Bank, Mizuho Securities USA, Apollo Global Funding and Sumitomo Mitsui Banking Corporation.SoftBank has now committed more than $60 billion to OpenAI and related infrastructure, and separately holds a $20 billion margin loan secured on its stake in Arm Holdings.
The terms of the newest facility make the dependency explicit.
The agreement requires SoftBank to post additional cash or repay early under adverse conditions, with a sharp fall in the value of OpenAI's preferred shares named as a trigger.
That links the group's near-term liquidity directly to a private-market valuation set by a small number of funding rounds rather than by daily trading.
The lenders priced that risk accordingly.
The loan carries a spread of 425 basis points over SOFR, nearly triple the 150 basis points SoftBank paid over LIBOR when it borrowed $8 billion against its listed Alibaba holding in 2018.The facility was originally sought at $10 billion, cut to $6 billion on valuation concerns, then restored once SoftBank added a corporate guarantee.S&P has moved its credit outlook on the group to negative.
The circularity is the risk. If OpenAI's valuation falls, SoftBank may be forced to sell shares into a weakening market, applying further downward pressure on the price of the asset securing its debt.
That outcome would damage both companies, which is why the timing of a listing matters so much.
OpenAI filed confidentially for a US initial public offering in June, which would convert illiquid private shares into stock the banks could actually sell.
Sentiment towards that flotation remains broadly positive, though it may be shaped by how Anthropic's listing is received first.
SoftBank is relying on the offering to mark its stake higher still.
