SoftBank shares surge as OpenAI’s GPT-5.6 launch fuels Asian rally

SoftBank Group shares surged more than 11% on Friday, briefly clearing ¥6,400, as investors cheered OpenAI's public release of its GPT-5.6 model family a day earlier. The rally made SoftBank the largest single contributor to Japan's Nikkei 225, which staged a sharp rebound of more than 1,400 points in morning trading.reuters

GPT-5.6 Sparks AI Optimism

OpenAI launched GPT-5.6 on Thursday, July 9, following weeks of delay prompted by U.S. government requests for safety evaluations of the advanced models. The release includes three variants — Sol, the flagship; Terra, a mid-tier option; and Luna, a lower-cost model — which CEO Sam Altman described as "orders of magnitude more efficient" than previous versions.cnbc+2

The company said Sol is 54% more token-efficient for coding tasks and called GPT-5.6 its "strongest cybersecurity model yet." OpenAI had initially limited access to a "small group of trusted partners whose participation has been shared with the government" in late June before receiving the green light for a broader rollout.techcrunch+2

Semiconductor Stocks Join the Wave

The AI enthusiasm rippled across Asian markets on Friday. In South Korea, SK Hynix and Samsung Electronics extended gains after a strong rebound session on Wednesday, when SK Hynix jumped nearly 9% and Samsung rose about 4% following a surge in the Philadelphia Semiconductor Index.finance.biggo

Kioxia Holdings, the Japanese memory chipmaker whose shares have risen roughly 600% in 2026 amid the AI-driven memory boom, also advanced. The company recently began shipping next-generation memory samples from its fabrication facility in northern Japan as data center demand continues to outstrip supply.reuters+1

SoftBank's AI Bet Pays Off

SoftBank's outsized move reflected its deep ties to OpenAI. The Tokyo-based conglomerate has been negotiating a $10 billion loan backed by its stake in the ChatGPT developer and recently launched a cybersecurity service built on OpenAI technology targeting Japan's largest companies. The company overtook Toyota Motor to become Japan's most valuable firm earlier this year on the strength of its AI investments.investing+2

The Nikkei briefly touched 69,184 during Friday's session, tracking overnight gains in the U.S. Philadelphia Semiconductor Index.finance.biggo