SoftBank plans a record 1 trillion yen retail bond sale, about $6.3bn, the largest by any issuer in Japan, to fund investment commitments to OpenAI. Analysts say banks were reluctant to take the risk, leaving the deal dependent on retail investors.

SoftBank has found a lender of last resort for its AI bet, and it is Japanese households. The group plans a record ¥1 trillion retail bond sale, about $6.3bn and the largest by any issuer in Japan, to fund its investment commitments to OpenAI.

International raters see it differently. S&P has SoftBank at BB+, one notch below investment grade, having revised its outlook to stable from negative in July.

The reason it is going to retail is not enthusiasm. “Banks are finding it difficult to take on the risk given weak deposit growth, the credit rating and the seven-year duration, leaving the deal more reliant on retail investors,” said Yuuki Fukumoto of NLI Research Institute, in a pattern that has already forced Oracle to find anchors outside the banking system.

It is also becoming routine. This is SoftBank’s third retail bond of the year, after raising ¥418bn in April and ¥260bn in June.