SoftBank's Record Market Cap Crown Faces a 260 Billion Yen Reality Check

SoftBank surpasses Toyota in market cap via Arm and OpenAI gains, but a 25% stock plunge and $1.9B hybrid bond sale test investor faith amid AI sector volatility.

Masayoshi Son just achieved what many thought impossible: SoftBank Group dethroned Toyota as Japan’s most valuable company, riding a wave of AI euphoria that pushed Arm Holdings to a near-quadrupling in 2026 and turned the OpenAI bet into a $25 billion profit machine. Yet the historic milestone arrives at an awkward moment. The stock has plunged more than 25% in seven trading days, and the conglomerate is in the middle of hawking 260 billion yen ($1.9 billion) in hybrid bonds to Japanese retail investors — a test of faith that pits ambition against a brutal AI sector sell-off.

The debt instrument carries a 5.12% coupon for the first five years, a 35-year maturity, and a face value of 1 million yen apiece. While it is booked as debt, both S&P and the Japan Credit Rating Agency treat 50% of the proceeds as equity, giving the company a marginal boost to its leverage profile. The yen-denominated notes will replace dollar-denominated hybrid bonds that become callable in July 2027, while SoftBank is simultaneously redeeming about $669 million in senior notes at par.

No one needed a reminder that AI valuations are fragile. Last week the Nasdaq shed more than 4.5% after Broadcom missed second-fiscal-quarter revenue estimates, sending the VanEck Semiconductor ETF down over 9% in a single session. Arm Holdings and Micron Technology each lost more than 13%. SoftBank absorbed a 6.1% hit in its regional trade and continued sliding on Wednesday to €33.49, marking another 5.45% daily drop. The annualized 30-day volatility now stands at 112%.

The financing push comes as SoftBank commits ever more capital to artificial intelligence. In March it raised a $40 billion bridge loan to fund follow-on investments in OpenAI and for general corporate purposes. The cumulative OpenAI stake, spread across multiple rounds, is expected to reach about $64.6 billion — roughly 13% of the ChatGPT developer. That bet alone contributed around $25 billion in profit, helping quadruple SoftBank’s net income to approximately 5 trillion yen. The group also holds 87% of Arm, whose stock surge has been a primary driver of SoftBank’s market cap ascent.

Debt watchers are divided on the sustainability of the strategy. S&P lowered its outlook on SoftBank from stable to negative after the $40 billion bridge loan, while analyst Gil Luria at Davidson describes the company as a highly leveraged wager on AI. Richard Kaye of Comgest counters that SoftBank’s loan-to-value ratio remains below 25%, providing a cushion. The 5.12% coupon on the new hybrid bond now serves as a visible benchmark for the market’s assessment of SoftBank’s credit story.

Shareholders will have a chance to shape the narrative at the annual general meeting on June 24. The agenda includes a formal amendment to the company’s charter to enshrine AI, semiconductors, and robotics as core business pillars, a proposed dividend of 5.5 yen per share, and the election of new independent directors aimed at strengthening oversight. For SoftBank’s investors, the question is whether the crown can withstand the weight of the debt needed to keep it there.