On September 24, SoftBank Group completed a $11.1 billion bond issuance (about 746.2 billion yuan at current exchange rates) to fund the final $10 billion tranche of its follow-on investment in OpenAI and for general corporate purposes. According to Benzinga and Sina Finance, the bonds include $10 billion of dollar-denominated senior notes (with interest rates of 8.625%, 9.25%, and 9.75%) and two euro tranches of 500 million euros each (4-year at 7.125%, 6-year at 8%). The final $10 billion tranche is expected to close on October 1, bringing SoftBank's cumulative investment in OpenAI to $64.6 billion. SoftBank shares jumped more than 7% on Thursday.
[1][2]The nut graf: this is not an ordinary refinancing but a move that feeds AI with debt-market money — Masayoshi Son did not complete his commitment to OpenAI through further equity financing; he borrowed from the bond market at coupon rates as high as 9.75%. The rate itself is a pricing signal: in 2026, with benchmark rates already lower, the risk premium the market attaches to this SoftBank AI bet is not trivial. In other words, bond investors are being asked to carry the earnings risk of the OpenAI story, and SoftBank has transferred that risk onto its own balance sheet through leverage. 90 91 The transaction's details deserve a layer-by-layer read. Structurally, the $11.1 billion breaks into three parts: $10 billion of dollar-denominated senior notes in three tranches (8.625%/9.25%/9.75%), plus two euro tranches of 500 million each (4-year at 7.125%, 6-year at 8%). The proceeds are earmarked for two purposes: the third and final $10 billion tranche of SoftBank's $30 billion follow-on investment in OpenAI (expected to close October 1), with the remainder for general corporate purposes. On the timeline, SoftBank prepaid the entire $25.9 billion bridge facility arranged for the OpenAI follow-on on September 15 (per its official September 9 announcement), completing a bridge-to-bond swap within a month. On scale, a $64.6 billion cumulative investment makes SoftBank the deepest external financial anchor on OpenAI's balance sheet — in the previous Stargate era SoftBank treated compute and data centers as its main battlefield; this round the battlefield is OpenAI equity plus debt leverage. 92 93 The implications for AI capital markets run three ways. First, funding sources for frontier AI are expanding from equity to the bond market: OpenAI's expansion no longer depends only on capital increases from major shareholders, but is supplied indirectly through its largest investor's debt financing, lengthening the transmission chain from the AI story to bond yields to SoftBank's stock. Second, Sina Finance's headline flags financing pressure: high-yield rates are the market's real pricing of SoftBank's leverage, and euro tranches above 7% plus dollar tranches near 10% say investors demand substantial risk compensation; a single-day stock gain above 7% coexisting with high bond coupons reflects a market that simultaneously endorses the AI narrative and worries about leverage. Third, for the OpenAI ecosystem, SoftBank's role deepens from largest investor to continuous capital supplier, and the cost of that supply eventually feeds back into the pace of AI infrastructure spending across the industry. 94 95 The measured judgment worth keeping: completing a bond issue is not investment landing; any change before the October 1 close would rewrite this balance-sheet story; SoftBank's leverage strategy amplifies in both directions when rates rise or OpenAI's valuation adjusts; and for simplified narratives like SoftBank as OpenAI's biggest backer, the $64.6 billion figure is a book-value view — actual cash deployment pace and exit arrangements are the harder metrics. The key variable in this round of the AI capital war has partly shifted from who has the model to who has the money to keep supplying capital, and how much interest they are willing to pay for the risk.
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