Nikkei rebounds above 64,000 as SoftBank leads AI stock recovery

Tokyo's stock market opened weak on the morning of September 15, but by midday had reversed course entirely. The Nikkei Stock Average closed up 589.37 points—a gain of 0.93%—at 64,082.36, ending a three-day slide that had rattled investors across Asia. The turnaround hinged almost entirely on a single stock: SoftBank Group, which had cratered more than 10% the day before but rebounded over 6% on the 15th, single-handedly contributing 428.81 points to the index's recovery. That outsized contribution revealed something important about the market's mechanics—a handful of high-priced names were doing the heavy lifting while the broader picture remained fractured.

The catalyst for the previous day's selloff had been a report that OpenAI would delay its planned year-end initial public offering. The news hit semiconductor and artificial intelligence stocks particularly hard, with the Philadelphia Semiconductor Index falling nearly 6% in U.S. trading. SoftBank, which has deep exposure to AI investments through its Vision Fund, bore the brunt of that panic. But by September 15, traders had begun to view the decline as overdone. The Tokyo market had already absorbed much of the U.S. tech weakness on the 14th, analysts reasoned, and the weak yen—trading in the low-154 range against the dollar—created an attractive entry point for export-focused companies. Buybacks began flowing into beaten-down semiconductor names, and the index reversed its opening deficit of 302.62 points within hours.

The recovery, however, was selective and uneven. On the Tokyo Stock Exchange Prime Market, advancing issues outnumbered decliners by a significant margin—887 stocks rose while 592 fell, with 68 unchanged. Trading volume reached 815.11 million shares, representing roughly ¥3.5593 trillion in turnover, or about $23 billion. Yet the broader TOPIX index actually declined 1.15 points to 4,057.06, a telling divergence that showed large-cap stocks were pulling the Nikkei higher while smaller and mid-cap names struggled. Of the 33 industry sectors tracked by the Tokyo Stock Exchange, only 13 advanced. Information and communications stocks led gainers, along with glass and ceramics, pharmaceuticals, and services. But banking, securities, and oil and coal sectors all fell, weighed down by rising crude prices and climbing interest rates in both Japan and the United States.

Beyond SoftBank, the recovery was anchored by other semiconductor and technology names. Advantest contributed 60.34 points, Recruit Holdings added 39.22 points, Kioxia Holdings contributed 32.38 points, and Ibiden added 30.17 points. On the losing side, Fast Retailing was the largest drag on the index at 26.55 points, followed by Toyota Tsusho, Konami Group, KDDI, and Nitori Holdings. The pattern illustrated a market in rotation—money flowing out of defensive and energy-sensitive names into technology and domestic-demand sectors.

Kentaro Shida, head of research at Yamawa Securities, offered a sobering assessment of the road ahead. The OpenAI IPO delay was one of several triggers that had pressured semiconductor stocks since late June, he noted, and the renewed confirmation that the listing had been shelved had accelerated selling. With earnings season having just concluded, Shida said, the market lacked clear catalysts for sustained gains. He expected semiconductor stocks to face "heavy upside resistance" until the next earnings cycle arrives. That forecast captured the underlying tension in the market: the rebound on September 15 was real, but it rested on thin ground. Macro headwinds—oil prices climbing amid Middle East uncertainty, interest rates rising in both Tokyo and Washington—continued to cap the broader market's upside. The Nikkei's recovery was a relief, not a resolution.