Nikkei 225 Loses 9.25% in Week to Nov 6, 2026 as AI Stocks Slump

Key takeaways

• The Nikkei 225 lost 9.25% in the week to Nov 6, 2026, closing at 57,434.77 at the 15:30 JST close (06:30 UTC) on Friday, down 5,855.34 points from 63,290.11 on Oct 30, according to Jiji Press closing data.
• Friday alone took 3,643.13 points (−5.96%) off the index, its third-biggest one-day point drop on record and its first close below 60,000 since May 20, Jiji Press reported.
• The broader TOPIX fell 6.48% over the week to 3,707.99 at the 06:30 UTC close on Nov 6, a smaller drop because the selling was concentrated in heavyweight chip and AI-linked shares.
• AI-linked stocks led the decline: Kioxia fell 36.82% over the week, SoftBank Group 20.80% and Advantest 19.64%, based on Yahoo Finance daily closes; Toyota Motor rose 8.73% after its Nov 5 results.
• Bonds drew haven demand: Investing.com data put the 10-year JGB yield at 2.628% on Nov 6, down from 2.776% on Oct 30, while USD/JPY was little changed at 158.29 at 09:31 UTC.

Week in review

Tokyo stocks had a four-session week, with the market shut on Tuesday, Nov 3 for Culture Day, and the Nikkei 225 fell in every session. The selling was driven by fears that the Democratic gains in the Nov 3 US midterm elections would bring tighter rules on AI data centres, Jiji Press reported. For the wider picture, see Asian and global market closes, last week's Nikkei 225 brief for Oct 30 and the Nikkei 225 brief for Nov 5.

The TOPIX intraweek high and low were not available from the sources reviewed. The USD/JPY prior-week figure is Yahoo Finance's Oct 30 daily close and the week figure is its 09:31 UTC Nov 6 quote, not a settled close; Jiji Press quoted the dollar at 157.94-96 yen at 5 p.m. in Tokyo.

Day by day

• Monday, Nov 2: the Nikkei 225 slipped 208.25 points (−0.33%) to 63,081.86 and the TOPIX lost 0.88% to 3,930.28, Jiji Press data show. Kioxia dropped 15.78% to 11,345 yen, according to Yahoo Finance; the sources reviewed did not give a reason.
• Tuesday, Nov 3: Tokyo was closed for a national holiday while US voters went to the polls.
• Wednesday, Nov 4: the Nikkei fell 893.23 points (−1.41%) to 62,188.63 after briefly losing more than 3,000 points, as vote counts pointed to Democratic majorities in both chambers of Congress. About 70% of Prime Market stocks declined, Jiji Press reported.
• Thursday, Nov 5: the Nikkei dropped 1,110.73 points (−1.79%) to 61,077.90, its lowest close since May 20, while the TOPIX rose 1.16% to 3,940.39. Jiji Press said technology stocks pulled the Nikkei down by about 1,800 points; Advantest fell 14.71% and Toyota jumped 16.68%, per Yahoo Finance closes.
• Friday, Nov 6: the Nikkei plunged 3,643.13 points (−5.96%) to 57,434.77 and the TOPIX fell 232.40 points (−5.90%) to 3,707.99. SoftBank Group lost 10.83% and Kioxia 8.72%, Jiji Press reported.

What drove it

US midterms and AI regulation fears

The main driver was politics in the United States. Jiji Press reported that investors sold AI- and data-centre-related shares on concern that tighter regulation favoured by Democrats could curb data-centre capital investment. On Friday, Reuters reported, in a story carried by Yahoo Finance, that the rout reflected fears of more regulatory scrutiny of AI and slower data-centre build-out, plus margin calls and forced selling among retail investors and hedge funds. Masahiko Loo of State Street Investment Management told Reuters: "This looks more like a reassessment of AI policy risk than a reassessment of the AI cycle."

Wall Street's tech sell-off

Friday's drop followed a heavy US session on Thursday, Nov 5. The Nasdaq Composite closed down 5.52% at 24,315.00 and the S&P 500 lost 4.36% to 7,353.73, according to Yahoo Finance closes, figures that match an Investing.com report. Losses spread across Asia: Taiwan's TAIEX closed down 4.51% at 39,701.64 on Nov 6, per Yahoo Finance, in line with the 4.5% drop reported by Reuters.

Index weights magnified the fall

The Nikkei 225 is price-weighted, so expensive chip and AI names carry outsized influence. Over the week Advantest fell from 34,860 yen to 28,015 yen and Tokyo Electron from 9,514 yen to 8,263 yen (−13.15%), Yahoo Finance data show. That is why the TOPIX, which is weighted by market value, fell less, and even rose on Thursday. Readers can compare the two benchmarks in our explainer on Nikkei 225 vs TOPIX.

Earnings: Toyota stood out

Toyota Motor was the week's main exception. Investing.com reported that its July-September operating profit rose 34% to 1.13 trillion yen, above a median analyst estimate of 992 billion yen, and that it raised its full-year operating profit guidance to 3.9 trillion yen from 3.4 trillion yen. Its shares closed at 3,533 yen on Nov 5, up 16.68%, and ended the week at 3,338 yen, according to Yahoo Finance.

Bonds and the yen

Equity losses pushed investors into government debt. Investing.com reported that the 10-year JGB yield hit its lowest level since June on Nov 6, in its steepest one-day decline since July. The yen moved far less than stocks: USD/JPY moved in a range of 157.60 to 158.77 during the week, Yahoo Finance data show.

Political & policy watch

• United States: after the Nov 3 midterms, Reuters reported that Texas Governor-elect Gina Hinojosa said the state will introduce laws to protect residents, amid rising local opposition to data centres. How Congress acts on AI rules is still unclear.
• Bank of Japan: the BoJ kept its policy rate at around 1.25% on Oct 30, according to its statement. Investing.com said the Nov 6 bond rally outweighed hawkish signals in the minutes of the BoJ's September meeting.
• Regional market support: Reuters reported that South Korea eased rules on retail leveraged investing and that Taiwan's finance ministry reportedly told state-owned banks to support the market. No similar step by Japanese authorities was reported in the sources reviewed.
• For how the election result fed into Southeast Asian assets, see US midterm results and ASEAN markets.

What to watch next

Risk checklist for readers

• The Nikkei 225 is price-weighted, so a few high-priced stocks can move it far more than the TOPIX; check both before drawing conclusions.
• Policy risk abroad can hit Tokyo quickly. This week, US election results moved Japanese AI and chip shares before any rule had been written.
• Forced selling, such as margin calls, can make price swings larger than the news itself; Reuters cited it as a factor this week.
• Scheduled events, including the Nov 16 GDP release and the BoJ's Dec 17-18 meeting, can shift yields, the yen and equities.
• For overseas investors, yen moves change returns in their home currency even when local prices are flat.
• Different data providers can show different yields and closing quotes; check official sources such as JPX, the Ministry of Finance and the Bank of Japan.

This article is for information only and is not investment advice.