On 15 October 2026, the Nikkei Stock Average fell ¥3,318.34 to ¥64,425.95, marking a sixth straight decline. US CPI, corporate bond trends and instability during earnings season were cited as the three factors behind the sharp fall in Japanese equities.
In the Tokyo stock market on 15 October 2026, the Nikkei Stock Average closed at ¥64,425.95, down ¥3,318.34 from the previous day, marking a sixth consecutive decline. At one point, the decline exceeded ¥3,600.
Following the decline in US equities, AI-related stocks, particularly semiconductor stocks, were sold in Japan. Three factors were cited behind the sharp fall. The first was the release of the September consumer price index (CPI), whose core index exceeded expectations and triggered the stock market decline.
The second was the sharp fall in bonds issued by neocloud companies, particularly CoreWeave bonds, which intensified concerns about the cost of AI infrastructure investment. The third was market nervousness over the start of earnings season and the performance of AI-related companies. The fact that TSMC was scheduled to announce its results on the 15th was also a source of concern.
The market's focus is shifting toward earnings from US hyperscalers. The Nikkei's forward 12-month P/E ratio is expected to be 15.0 times. Although this is below its historical range, there was a view that signs of excess in the AI boom remained limited.