Nomura sees AI・半導体株ラリー pausing through late October

Nomura's view rests on a pattern it has tracked since mid-September, when the AI and semiconductor rally gained momentum. The weaker September US jobs report, published on October 2, pushed back expectations of US rate hikes and added to the rally, but Nomura notes that such initial boosts rarely last — in past cases, US and Japanese stock gains tended to run their course in about 20 business days.

The firm also points to political and reputational factors. US midterm elections have historically been followed by stock gains regardless of outcome, but Nomura notes markets can be vulnerable to unexpected negative surprises, and says stocks tend to move sideways before the vote. It flags the 1994 and 2018 rate-hike concerns and the 2002 accounting scandal as cases where post-midterm stock performance was weak.

Separately, Nomura says concerns about AI development slowdown and circular transactions have recurred periodically since autumn 2025. A BIS report published on October 1, 'Circular relationships among AI firms,' renewed focus on circular transactions in AI and semiconductors, warning of a risk that stock drops and sales declines occur simultaneously after a negative shock. Nomura says this is not new but, alongside rising interest rates and AI slowdown worries, could weigh on price-to-earnings ratios. In Japan, Nomura sees a rotation market with repeated reversals, and says AI and semiconductor shares have somewhat less valuation appeal now.