Tokyo reopened from an extended three-day holiday with a distinctly two-speed session on Thursday, September 24. The Nikkei 225 climbed 0.76% to 65,513.99, briefly crossing 66,000 intraday, powered by a catch-up rally in AI and semiconductor names. The broad market told a different story: our TOPIX proxy (1306 ETF) slipped 0.35% to 424.80, and only 7 of 17 sector proxies advanced. Part of that gap is mechanical — this is the fiscal half-year-end ex-dividend cluster week, and dividend drop-offs distort index arithmetic — but the leadership concentration in chips was real either way. The yen added its own edge to the session, with USD/JPY up 0.59% to 158.40 and intervention chatter never far from traders’ minds.
The Day’s Tape: Chips Up, Yield Names Down
Semiconductor-adjacent names did the heavy lifting. Advantest gained 3.15% to 33,060 and Tokyo Electron 1.53% to 53,920 on persistent demand tied to AI test systems and wafer fabrication equipment. Within our fixed 95-name large-cap universe, the top movers were Renesas (+5.47% on 1.7x average volume), Panasonic (+5.16%, 1.6x), SCREEN (+3.87%), TDK (+3.85%, 1.7x) and SMC (+3.29%). On the TOPIX-17 ETF proxies, Electric & Precision led at +2.27% (+2.62pp versus TOPIX, +5.3% over five days), followed by Machinery (+1.59%) and Raw Materials & Chemicals (+1.04%).
The losing side of the ledger was dominated by high-dividend financials, utilities and trading houses — consistent with ex-dividend mechanics, though not all of it reduces to that. Recruit fell 7.78% on 1.4x volume, the day’s standout idiosyncratic decline. MS&AD lost 4.73% on heavy 1.9x volume, TEPCO 4.42%, Itochu 3.73% and Tokio Marine 3.27%. At the sector level, Power & Gas (-2.78%), Financials ex-Banks (-1.78%) and Trading & Wholesale (-1.75%) lagged. Among the megacaps, Toyota shed 1.85% to 2,969 despite the weak yen’s nominal support for exporters, while Sony fell 0.92% and MUFG 1.30%. SoftBank Group added 0.59%. Fast Retailing edged up 0.35%.
Notably, the Nikkei Volatility Index jumped 3.88 points to 28.11 — the 74th percentile of the last 910 sessions — an unusual pairing with an up day for the headline index, and a hint that options markets are not treating this rally as low-risk.
Positioning: Short Ratio Mid-Range at 41.0%
The TSE short-selling ratio — this site’s daily positioning signature — came in at 41.0% of Thursday’s JPY 10.04 trillion turnover (33.6% under the price rule, 7.4% unrestricted). That sits in the middle third of the last eight sessions’ 38.1%–44.9% range, almost exactly on the 41.1% average: neither the defensive crouch an elevated reading would signal, nor any real short-covering relief.
The latest JSF standardized-margin data (September 18 session; today’s print is not yet published) showed leveraged long demand of JPY 0.65 trillion against JPY 0.19 trillion of stock lending on the short side. The single most interesting line: Advantest’s stock-lending balance jumped 37,300 shares while its margin-buy balance fell 92,700 — shorts were leaning into chip strength going into the holiday, which makes Thursday’s 3.15% gain expensive for them. Toyota saw the opposite: margin buying up 157,500 shares. Squeeze costs remain broad, with 380 of 900 loanable issues (42%) incurring gyaku-hibu premium charges — the extra daily fee short sellers pay when borrow gets tight. The wider JPX margin data (to September 11) showed retail leverage still long-skewed: JPY 6.65 trillion of margin buying versus JPY 0.80 trillion of margin selling.
For completeness, the September 18 batch of large disclosed short positions ran to 761 reports across 567 issues, led by ReYuu Japan (12.4% aggregate) and TOWA (10.5%). These are lagged regulatory position filings — a map of where shorts are camped, not a driver of today’s move.
Rates and the Yen
Markets are still metabolizing the Bank of Japan’s September 18 hike to 1.25% — the highest short-term policy rate since 1995 — with dissents from board members Ayano Sato and Toichiro Asada read as a signal that further normalization will be measured. MOF’s last official fixings (September 18) had the 10-year JGB at 2.981% and the 30-year at 4.044%. Against that backdrop, USD/JPY at 158.40 keeps the intervention question live. The overnight US handoff was soft — the S&P 500 fell 0.76% to 7,706.03 on Wednesday — and S&P futures traded around 7,726 during Tokyo hours, a -0.60% setup.
Weekly Flows
The latest JPX investor-type data covers the week of September 7–11 — weekly figures published with a lag, not today’s flows. On TSE Prime, foreign investors were net buyers of JPY 0.73 trillion while individuals net sold JPY 0.05 trillion. A caveat worth flagging: MOF’s cross-border securities data for essentially the same week (September 6–12, a different reporting basis) showed foreigners as net sellers of JPY 1.52 trillion of Japanese equities. When the two series disagree on direction, we treat the foreign-flow read as unresolved rather than picking a side.
What to Watch
- Ex-dividend mechanics through half-year-end week. Nikkei–TOPIX divergence and weakness in high-yield financials, utilities and trading houses may be partly optical — watch whether those names recover the drop-off.
- USD/JPY near 158.40. Any official rhetoric escalation is the swing factor for exporters, with Toyota already trading defensively despite the currency tailwind.
- The Advantest short build. The pre-holiday stock-lending build in the September 18 JSF data, which preceded Thursday’s 3.15% gain, with gyaku-hibu charges already touching 42% of loanable issues, sets up either an orderly unwind or squeeze fuel — the next JSF prints and the daily short ratio will tell.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.