The Session: A Tug-of-War That Ended in a Draw
Tuesday’s Tokyo session was a stalemate with a lot of movement underneath it. The Nikkei 225 closed at 63,484.10, down a rounding-error 0.01% — its third straight decline, but only just. The index opened more than 300 yen lower after Monday’s sharp sell-off in US AI and semiconductor names, then spent the day swinging between gains and losses. TOPIX, tracked here via the 1306 ETF proxy, fared better, adding 0.38% — a reminder that the pain was concentrated in the index heavyweights rather than the broad market.
The single biggest stabilizer was SoftBank Group (9984), which surged 7.54% on volume 1.5x its 20-day average — the session’s dominant stabilizing force among the index heavyweights. Set against that, Advantest (6857) fell 2.96% as afternoon selling in semiconductors intensified, Tokyo Electron (8035) lost 0.55%, and Sony (6758) dropped 1.66%. MUFG (8306) shed 1.40% amid weakness in banks. The yen offered no support to the bears: USD/JPY was quoted around 154.9 in Tokyo trade, up close to 1% on the day, as markets positioned for this week’s central bank decisions.
| Tuesday’s readings | Level | Change |
|---|---|---|
| Nikkei 225 | 63,484.10 | -0.01% |
| TOPIX (1306 proxy) | 421.30 | +0.38% |
| USD/JPY (late Tokyo quote) | ≈154.9 | up ~0.9% |
| Nikkei VI | 30.68 | -0.38 |
| 10y JGB (MOF, Sep 14) | 2.988% | +0.1bp |
Sectors and Movers
Using TOPIX-17 ETF proxies (Nomura NEXT FUNDS closes, which can deviate slightly from official sector indices), 9 of 17 sectors advanced. Pharmaceuticals led at +2.42%, with Takeda (4502) up 1.92% among the large caps. IT & Services rose 2.36% — the SoftBank effect writ large — and Financials ex-Banks added 1.23%. The laggards were unambiguous: Steel & Nonferrous fell 2.98% and is now down 5.8% over five sessions, Energy Resources lost 1.44%, and Trading & Wholesale slipped 0.79%, with Marubeni (8002) down 2.73%.
Within our fixed 95-name large-cap universe (not a full-market scan), the other notable gainers were Murata (6981) +3.24%, Lasertec (6920) +3.22% and Recruit (6098) +2.18% — semiconductor-adjacent names rebounding even as Advantest sank, underscoring how uneven the chip trade has become. On the losing side, SMFG (8316) fell 2.67%, Mitsubishi Estate (8802) 2.58% and Nitori (9843) 2.46%.
Positioning: The Short-Sell Ratio Eases Off the Highs
Our daily signature stat: short sales made up 39.9% of Tuesday’s JPY 8.22 trillion in TSE turnover (31.3% price-rule restricted plus 8.6% unrestricted). That sits in the lower third of the past eight sessions’ 38.1%–44.9% range, below the 41.5% average — in plain terms, still a defensive tape by historical standards, but noticeably less defensive than it has been recently. The Nikkei VI told a similar story, ticking down 0.38 to 30.68, though that is still the 84th percentile of the last 906 sessions. Nerves are calming at the margin, not gone.
The squeeze-cost side of the ledger remains hot. Per Monday’s JSF data (Tuesday’s is not yet published), 402 of 926 loanable issues — 43% — incurred gyaku-hibu premium charges, the extra daily fee short sellers pay when borrowable stock runs tight. JSF standardized margin balances from the same session showed loans for margin buying (leveraged long demand) at JPY 0.63 trillion against JPY 0.18 trillion of stock lending on the short side. Notably, SoftBank Group’s margin-loan balance jumped 234,400 shares to 3,050,800 on Monday — leveraged longs were building into the name a day before its surge — while Sony’s stock-lending balance rose 19,200 shares, a sign of fresh borrowing to short ahead of Tuesday’s 1.66% drop.
On the regulatory side, JPX published 1,033 large disclosed short positions across 686 issues on Tuesday. These are lagged position filings, not today’s selling: the biggest aggregate disclosed shorts sit in ReYuu Japan (16.7%), TOWA (14.6%) and Sanrio (11.3%), with Sanrio also showing the largest increase versus prior reports at +2.53pp. Worth flagging too: a +1.97pp build in disclosed shorts against the Nikkei 225 Leveraged ETF (1570), a common vehicle for index-level bearish positioning.
Weekly Flows
The latest JPX investor-type data covers the week of August 31 to September 4 — these are weekly figures published with a lag, not Tuesday’s flows. Foreign investors were net sellers of JPY 0.17 trillion on TSE Prime, and individuals net sold JPY 0.05 trillion. One caveat: MOF’s independent cross-border series for roughly the same week (Aug 30–Sep 5, different reporting basis) shows foreigners as net buyers of JPY 0.69 trillion of Japanese equities, so the foreign-flow picture is genuinely mixed rather than cleanly negative. Meanwhile, margin buying balances across Tokyo and Nagoya rose JPY 0.17 trillion week-on-week to JPY 6.65 trillion as of September 11 against just JPY 0.80 trillion of margin selling — retail leverage keeps leaning long.
The BOJ Looms
The macro overhang is Thursday-Friday’s Bank of Japan meeting (September 17–18), where markets are watching for whether the bank takes a further tightening step. The JGB curve is already priced for a tighter world: per MOF data through Monday, the 10-year sits at 2.988%, the 30-year at 4.040%, with the long end still drifting higher (+1.6bp on the day for the 30-year). The yen’s slide toward 155 despite those expectations of tighter policy is part of what keeps pressure on the BOJ to move.
What to Watch
- BOJ decision, Sep 17–18: whether the bank tightens policy further and, more importantly, the guidance around the pace of any additional moves, with USD/JPY around 154.9 and the 10-year JGB near 3%.
- Semiconductor follow-through: S&P 500 futures were up 0.46% overnight after Monday’s 0.48% cash decline — whether that stabilizes Advantest and Tokyo Electron will decide if Tuesday’s flat close was a floor or a pause.
- The short-sell ratio: at 39.9% it has slipped to the bottom third of its recent range; a further drift lower alongside a Nikkei VI retreat from the 84th percentile would signal the defensive crouch is genuinely unwinding.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.