SoftBank Group Corp. shares climbed sharply on Monday, reaching a record intraday price as investor optimism tied to artificial intelligence helped push the conglomerate past Toyota Group to become the most valuable company in Japan by market capitalization.
The stock rallied more than 13% to a record 8,546.0 yen. SoftBank was among the largest contributors to gains in the Nikkei 225, which rose about 1% on the session.
Monday’s advance placed SoftBank’s market value at about 48 trillion yen, or $305.8 billion, a peak level for the company.
Why investors moved into the shares
Market enthusiasm centered on SoftBank’s exposure to chipmaking and AI processors through its majority stake in Arm Holdings. Arm’s technology platform is slated to be used in a range of new processors unveiled earlier on Monday by NVIDIA Corporation, and Nvidia has developed Arm-based chips for Windows devices in collaboration with Microsoft Corporation.
The structure of Arm’s business model is important to the calculus: the British chip designer earns most of its revenue from licensing fees for its chip architecture. Because Arm’s technology can be licensed broadly, analysts and investors view successful product integrations as likely to translate into material revenue streams for Arm and, by extension, for SoftBank as the primary owner.
SoftBank retains roughly 90% ownership of Arm. Arm’s shares have more than tripled in value so far in 2026, following a substantial rally over the prior two years. That performance has been a major factor in the upward momentum of SoftBank’s stock this year; SoftBank shares are trading up more than 80% so far in 2026.
Other contributors to the rally
In addition to Arm-related optimism, SoftBank disclosed a sizable gain tied to its investment in AI startup OpenAI, a disclosure that has been cited as another recent catalyst for the company’s share-price strength.
Separately, over the weekend SoftBank pledged about 75 billion euros, equal to $87.3 billion, to build AI infrastructure in France over the next five years. That commitment forms part of the broader narrative that has supported investor interest in the group.
Market context and limitations
The jump in SoftBank’s share price on Monday was driven chiefly by market optimism around AI and chip-related assets in its portfolio, particularly Arm. While those factors have produced dramatic price moves in 2026, the future trajectory of returns remains tied closely to the commercial performance of licensed chip technology and gains from the company’s AI-related investments.