AI Heavyweights Lift the Nikkei as a Stronger Yen Splits Tokyo

What Moved Tokyo

Monday looked spectacular through the Nikkei: a 1,378.90-point jump restored the index to 66,399.84. The broader evidence was less euphoric. TOPIX gained only 0.55%, one quarter of the Nikkei’s percentage move, because a small set of expensive AI and chip-linked shares—especially SoftBank Group, Advantest and Tokyo Electron—did much of the lifting.

Tuesday exposed that concentration. At the lunch break the Nikkei was up just 45 points while TOPIX had lost 23.75; only 430 Prime Market shares had risen against 1,070 decliners. The Nikkei strengthened after trading resumed, yet TOPIX remained negative. A seven-month high in the yen pressured autos, machinery and electronic components while selected AI names continued to dominate the price-weighted Nikkei.

Sector Pulse

Yen Watch

The yen reached ¥152.89 per dollar in morning trade, its strongest level since February, before easing toward ¥153.3. It has moved roughly 4.5% from levels near ¥160 early last week. Faster BOJ-tightening expectations, the unwinding of short-yen positions and speculation about the repatriation of Japanese capital all contributed.

That move redistributes rather than simply creates value. Importers and households may receive relief through cheaper yen costs for oil, food and industrial inputs. Exporters translate foreign revenue into fewer yen, and inbound visitors lose some purchasing power. Tuesday’s market split showed those channels operating in real time.

Rates / JGB Watch

The public 10-year JGB yield indication eased from roughly 2.93% Monday to about 2.89% Tuesday. A stronger currency can reduce imported inflation pressure, while the bond market also recovered from the previous week’s test of 3%.

That retreat did not produce a simple equity rally. Lower yields can help long-duration growth shares, but yen appreciation simultaneously hurt exporters. Banks lost some support from the prospect of wider lending margins. Japan’s revived interest-rate market now interacts with equities and currencies in more than one direction at once.

Global Handoff

Wall Street was closed Monday for Labor Day, leaving Tokyo without a fresh U.S. cash-market close. During Tuesday’s Asian session, the KOSPI gained about 1.2%, S&P 500 futures slipped 0.1%, and the U.S. 10-year Treasury yield stood near 4.788%.

Brent crude traded above $97 a barrel as tensions in the Gulf kept energy risk elevated. For Japan, a stronger yen offsets part of the dollar oil increase but cannot erase it. The next European and U.S. sessions will test whether the AI bid, high global yields and expensive energy can continue to coexist.

Policy / BOJ Watch

The BOJ held its overnight call-rate target near 1% in July, although board member Hajime Takata proposed 1.25%. The next meeting is scheduled for September 17–18. Tuesday’s revised second-quarter GDP figures and a 2.4% annual increase in July real wages strengthened the case that domestic conditions may tolerate another move.

Markets are already tightening the environment through the currency. If the yen rises too quickly, policymakers must consider not only inflation and wage persistence but also the financial impact of the move itself. That makes the path to the September decision less mechanical than the day’s rate-hike speculation suggests.