The Session
The Nikkei 225 finished Thursday, September 17 at 64,136.25, up 213.25 points (+0.33%) — a respectable close that conceals a much stronger open. The index surged more than 700 points in the morning on relief that the Federal Reserve’s policy action had been fully priced in, then spent the afternoon giving most of it back as attention shifted to the Bank of Japan’s decision due Friday and an extended holiday weekend. The broader market held up better: the TOPIX-tracking 1306 ETF closed +0.83% at 427.40, comfortably ahead of the headline index.
The yen did its part for exporters, with USD/JPY at 155.79 (+0.34%) at Tokyo’s close after trading a 155.50–156.40 range on post-Fed dollar strength. The overnight lead was mixed: the S&P 500 fell 0.45% to 7,551.81 in Wednesday’s US session, but S&P futures were up 1.54% at 7,673 during Tokyo hours — the tailwind behind the morning pop.
Among the megacaps, SoftBank Group rose 1.04% to 6,247, Fast Retailing added 1.00% to 67,700, Sony gained 0.94% to 3,754, and Toyota closed +0.60% at 3,034. MUFG was flat at 3,652 (-0.08%). The soft spot was chip equipment: Tokyo Electron fell 1.39% to 50,970 and Advantest lost 1.50% to 30,240.
Sectors and Movers
Fourteen of seventeen TOPIX-17 sectors advanced, per Nomura NEXT FUNDS ETF proxies (which can deviate slightly from official sector indices). Real Estate and Pharmaceuticals shared the lead at +2.35% each, both roughly 1.5 points ahead of TOPIX, with IT & Services close behind at +2.01%. Energy Resources (-0.53%) and Retail (-0.52%) lagged.
Within our fixed 95-name large-cap universe (not a full-market scan), the leaderboard read:
| Gainers | Losers |
|---|---|
| Nintendo +4.29% | INPEX -3.23% |
| MOL +4.04% | SCREEN -2.76% |
| Mitsubishi Heavy +4.01% | Panasonic -2.72% |
| Chugai +3.69% | Nomura -2.69% |
| Eisai +3.51% | Murata -2.65% |
Chugai and Eisai carried the pharma leadership; INPEX’s slide matched the Energy Resources lag at the sector level. Nomura’s 2.69% drop stood out for its volume — 1.6x the 20-day average, the heaviest turnover ratio on either list.
Positioning: The Short-Selling Tape
Short sales accounted for 41.4% of Thursday’s TSE trading value (33.8% under the price rule plus 7.6% unrestricted), against total turnover of JPY 7.83 trillion. That is an elevated, defensive reading in absolute terms — but it sits in the middle third of the last eight sessions’ 38.1%–44.9% range, right around the 41.9% average. Hedging remains heavy; it did not escalate into the BOJ meeting.
The Japan Securities Finance standardized-margin data (September 16 — the previous session; today’s figures publish later) showed loans for margin buying at JPY 0.65 trillion against JPY 0.17 trillion of stock lending on the short side. The SoftBank Group detail is worth a look: stock-lending balances fell by 85,000 shares (short covering) while margin-loan balances jumped 213,600 shares — leveraged longs adding exposure into the BOJ decision. Sony, Advantest and Tokyo Electron each saw modest stock-lending increases, small in absolute size.
Squeeze costs remain broad: 375 of 882 loanable issues — 43% — incurred gyaku-hibu premium charges, the extra daily fee short sellers pay when borrow is tight. JSF also has 330 issues under new-application suspension and 160 under caution alerts; notably, the TOPIX-17 Real Estate ETF (1633) drew a caution alert on September 15, two days before that sector topped Thursday’s leaderboard.
On the regulatory side, JPX published 819 large disclosed-short-position reports across 575 issues on Thursday. These are lagged position filings — positioning context, not today’s selling. The largest single change was GA technologies, where disclosed shorts fell 1.82 percentage points versus prior reports.
The Nikkei Volatility Index eased 0.29 to 28.15, still the 75th percentile of the last 908 sessions — options are pricing meaningful event risk into Friday.
Rates
The JGB curve rallied modestly into the meeting, per MOF data through September 16: the 10-year at 2.998% (-3.0bp on the day) sits just under the 3% line, the 2-year at 1.852%, and the 30-year at 4.075% (-3.1bp).
Weekly Flows
For the week of September 7–11 — weekly data, not Thursday’s flows — JPX reported foreign investors as net buyers of JPY 0.73 trillion in TSE Prime cash equities, with individuals modest net sellers at JPY 0.05 trillion. A caveat this week: MOF’s cross-border securities data for roughly the same window (September 6–12, major reporters, a different reporting basis) showed foreigners as net sellers of JPY 1.52 trillion. When the two series disagree on direction, we treat the foreign-buying signal with caution rather than taking either number at face value. Margin buying balances (Tokyo+Nagoya, through September 11) rose JPY 0.17 trillion week-on-week to JPY 6.65 trillion against JPY 0.80 trillion of margin selling — retail leverage still leans long.
What to Watch
- BOJ decision, Friday September 18. Consensus per Thursday’s reports looks for a hike to 1.25%. With USD/JPY at 155.79 and officials reiterating currency-volatility monitoring, the yen reaction is the main event.
- The short-sell ratio’s 38–45% band. A post-decision break above the recent 44.9% high would signal fresh defensiveness; a slide toward 38% would suggest hedges unwinding.
- Holiday-weekend gap risk. With Japan heading into an extended weekend and S&P futures up 1.54% during Tokyo hours, the re-opening print could inherit several sessions of offshore moves at once.
Disclaimer: This is an information and analysis publication, not investment advice. See our Methodology for data sources, standards, and our corrections policy.