SoftBank Group Corp. (TYO:9984) continued its sharp rebound on Monday, with shares climbing 8.26% by the midday break to ¥6,052, extending a two-session gain to 21.02%. The surge, which began on Friday, has added approximately ¥5.99 trillion in equity value based on the company's June share count, underscoring renewed investor enthusiasm for its AI-related holdings.
The rally coincides with the opening of subscriptions for a ¥1 trillion retail bond offering, carrying a 4.75% coupon and maturing in September 2033. The bond sale, aimed primarily at Japanese retail investors, is part of SoftBank's broader financing strategy to support its expanding artificial intelligence portfolio, including recent investments in OpenAI and its stake in Arm Holdings.
Two-Day Surge Outpaces Bond Proceeds
The magnitude of the stock move is notable: the two-day increase in market capitalization is nearly six times the face value of the new bond. On Friday, SoftBank shares jumped 11.78% to ¥5,590, buoyed by gains in Arm Holdings and a strong performance in the PHLX Semiconductor Index. Monday's rally continued in Tokyo, with the Nikkei 225 adding 2.21%, although market breadth was negative, with more decliners than advancers on the Prime Market.
SoftBank alone contributed roughly 372 points to the Nikkei's rise, according to Minkabu's index-contribution calculation. The concentrated move highlights the market's focus on SoftBank as a bellwether for AI and semiconductor sentiment.
Higher Financing Costs Ahead
The new bond's 4.75% coupon represents a significant step-up from SoftBank's existing debt. Japan's seven-year government bond yields 2.493%, meaning SoftBank is paying a premium of 225.7 basis points. The company plans to use part of the proceeds to redeem existing domestic bonds, including two retail bonds totaling ¥497.9 billion with 1.38% coupons that mature this month.
This refinancing comes at a time when SoftBank's interest expenses are already rising sharply. In the June quarter, interest expense surged 98.9% year-over-year to ¥265.8 billion, driven by higher borrowing costs and new loans, including a margin loan backed by Arm shares. Consolidated cash fell by ¥1.44 trillion to ¥3.93 trillion during the quarter, though the company raised ¥5.56 trillion and repaid ¥3.94 trillion across the group.
Arm's Influence Remains Central
SoftBank's adjusted stake in Arm Holdings was valued at ¥49.91 trillion at the end of June, representing 60% of its adjusted holdings and 69% of net asset value. This concentration means that fluctuations in Arm's stock price have an outsized impact on SoftBank's valuation. While higher Arm prices boost collateral value, they also amplify downside risk if semiconductor valuations reverse.
Beyond Arm, SoftBank continues to deploy capital into AI ventures. The company reported $44.6 billion in investments by June 30, with an additional $10 billion in July, and plans a further $10 billion tranche on October 1, subject to terms.
Key Tests Ahead
The Tokyo close on Monday will be the first test: a finish at ¥6,001 or higher would preserve a two-session gain of at least 20%. The second test will be the bond subscription period, which runs until September 16. Strong demand would confirm access to Japan's deep household savings, but it also locks in a higher coupon for SoftBank's AI expansion.
As the market digests these developments, investors are weighing the benefits of SoftBank's aggressive AI strategy against the rising cost of financing. The two-day surge suggests optimism, but the sustainability of this momentum will depend on continued strength in Arm and broader tech sentiment.
