SoftBank shares jump over 7% after $11.1 billion bond issuance

SoftBank Group shares jumped more than 7% on Thursday, the first trading session in Japan after a three-day holiday, as the technology investor announced an $11.1 billion bond issuance to bankroll its expanding stake in OpenAI.

SoftBank said it issued $10 billion in dollar-denominated senior notes and 1 billion euros ($1.14 billion) in euro-denominated notes. The company will use the proceeds to fund a $10 billion payment for the third and final tranche of its $30 billion follow-on investment in OpenAI, which is expected to close Oct. 1. The remainder goes to general corporate purposes.

The bond sale underscores the scale of CEO Masayoshi Son's push into artificial intelligence. SoftBank agreed to the $30 billion investment in February. Once the final tranche closes, its cumulative investment in the ChatGPT maker will reach $64.6 billion, giving the Japanese conglomerate an approximately 13% stake.

The stakes are considerable for both SoftBank and the broader AI investment climate. Son has staked the company's future on OpenAI and the artificial intelligence buildout, and the market's 7% vote of confidence on Thursday suggests investors are, for now, comfortable with that concentration of risk in a single private AI company.

The welcome was not guaranteed. The latest fundraising comes as investors have increasingly scrutinized how SoftBank will finance its sprawling AI ambitions and the impact of rising leverage on its balance sheet. Debt-funded commitments of this size leave SoftBank exposed if OpenAI's valuation or commercial prospects deteriorate, and the Oct. 1 closing date puts a hard deadline on the capital.

The structure of the raise — a split between dollar and euro tranches — also signals SoftBank's willingness to tap multiple debt markets to meet its AI funding needs. With the $30 billion follow-on now nearly complete, attention shifts to how Son finances any further commitments and whether OpenAI's growth justifies a $64.6 billion concentrated position.