China's metals markets enter National Day with sharply lower aluminium ingot inventories, tight copper cathode availability and deeply negative zinc treatment charges. But the picture is not uniformly tight: aluminium billet remains abundant, zinc galvanising activity is weakening and nickel continues to carry substantial physical buffers. The first post-holiday inventory readings will separate seasonal restocking from more persistent tightness.
TL;DR
- Primary aluminium-ingot social inventories fell 118,000 tonnes in two weeks, including 55,000 tonnes in the week to 24 September.
- Aluminium billet inventory stood at 149,000 tonnes, still 26,000 tonnes above last year, while cast aluminium-alloy inventory fell 2,700 tonnes to 31,800 tonnes, ending a six-week build.
- Nationwide mainstream-region copper social inventory fell 16,500 tonnes week on week to around 70,000 tonnes, with much of the draw concentrated in south China.
- Guangdong high-quality cathode premiums rose from RMB700/t last week to RMB900/t on 18 September and held around that level through 21 September, surviving the contract roll.
- Zinc's imported concentrate TC fell to −$130.40/dmt, while domestic Zn50 TC remained around −RMB2,100 per metal tonne. Galvanising operating rates fell to 53.39%.
- Secondary-lead finished-product inventory fell from 12,400 tonnes to 8,000 tonnes ahead of the holiday.
- China imported 19,331.99 gross tonnes of tin ore and concentrate in August, up 88.4% year on year, although refined-tin inventories remain low.
China Metals Signal Board
| Metal | Key physical signal | Latest reading | Weekly direction | What changed |
|---|---|---|---|---|
| Copper | Mainstream-region social inventory | ~70,000t | ↓ 16,500t | Bulk of national draw concentrated in south China |
| Shanghai social inventory | 46,300t | ↑ 2,400t | Small regional rebuild | |
| Jiangsu social inventory | 18,200t | ↓ 2,400t | Regional draw | |
| Guangdong high-quality premium | ~RMB900/t | ↑ | Up from RMB700/t last week; held through contract roll | |
| Shanghai #1 cathode premium | ~RMB1,315/t | ↓ | Off weekly peak near RMB1,375/t as restocking faded | |
| SHFE inventory | ~47,100t | ↓ | Exchange stocks remain tight | |
| Aluminium | Primary ingot inventory | n/r | ↓ 55,000t | ↓118,000t over two weeks |
| Billet inventory | 149,000t | ↓ | Still 26,000t above last year | |
| Billet outbound volume | 45,100t | ↑ 6,200t | Second consecutive weekly increase | |
| Cast aluminium-alloy inventory | 31,800t | ↓ 2,700t | Six-week inventory build ended | |
| Zinc | Imported concentrate TC | −$130.40/dmt | ↓ $1.55 | Concentrate conditions tightened further |
| Domestic Zn50 TC | ~−RMB2,100/metal t | → | Remains deeply negative | |
| Galvanising operating rate | 53.39% | ↓ 1.1pp | Downstream demand weakened | |
| SHFE/LME ratio | ~6.8 | — | Export window remains open, but profitability has narrowed | |
| Lead | Secondary finished-product inventory | 8,000t | ↓ 4,400t | Strong pre-holiday destocking |
| Primary lead inventory | 2½-year low | ↓ | Holiday stockpiling reduced available stocks | |
| Nickel | IMIP affected RKEF load | −30–40% | ↓ | Water constraints reduced Indonesian NPI production |
| China NPI 10–12% | ~$137.43/Ni unit | ↓ | Disruption has not produced a strong price response | |
| Imported Indonesian NPI | ~$137.82/Ni unit | — | Chinese physical buffers remain ample | |
| Tin | Ore & concentrate imports | 19,331.99 gross t | ↑ 14.0% MoM | August imports ↑88.4% YoY |
| Myanmar ore supply | 7,395.46 gross t | ↑ 61.84% MoM | ↑253.55% YoY | |
| Refined tin imports | 2,746.85t | ↑ 21.04% MoM | ↑111.88% YoY | |
| Refined tin exports | 2,202.10t | ↑ 26.18% MoM | China remained a ~545t net importer |
n/r = the weekly change is published without a corresponding inventory level; it does not mean zero. Inventory series cover different products and geographies and should not be aggregated.
Weekly Signal
Tightening: Copper cathode, aluminium ingot, zinc concentrate, lead inventories and refined tin.
Improving supply/inventory: Aluminium billet outflows, the reversal in cast aluminium-alloy inventories and tin ore and concentrate imports.
Weak demand / ample buffers: Zinc galvanising, nickel/NPI and construction aluminium.
Key change: Aluminium. The 118,000-tonne two-week ingot draw is the strongest new inventory signal, while cast alloy has finally broken its six-week accumulation. Billet remains sufficiently abundant to prevent a broad aluminium-scarcity conclusion.
Copper
China's physical copper market remains tight, although the pre-holiday restocking impulse is beginning to fade.
The nationwide SMM mainstream-region social-inventory reading fell 16,500 tonnes week on week to around 70,000 tonnes. Shanghai itself moved the other way, rising 2,400 tonnes to 46,300 tonnes, while Jiangsu fell 2,400 tonnes to 18,200 tonnes. Those two regions therefore broadly offset one another; SMM attributes the bulk of the national draw to south China.
That regional distinction matters because Guangdong has been one of the strongest physical signals in recent editions. High-quality cathode premiums there, which stood around RMB700/t last week, rose to roughly RMB900/t on 18 September and held around that level through 21 September. The premium therefore survived the contract roll rather than collapsing afterwards, answering one of last week's principal monitoring points in favour of continued physical tightness.
Shanghai premiums have subsequently begun to ease. Shanghai #1 cathode reached roughly RMB1,375/t during the week before falling towards RMB1,315/t by 24 September as downstream companies completed much of their National Day purchasing. SHFE exchange inventory has separately fallen to roughly 47,100 tonnes; it is a different inventory pool from SMM's social series and should not be combined with it.
Upstream conditions remain constrained. The China Smelters Purchase Team did not set a Q4 copper-concentrate TC guidance price at its latest meeting, against deeply negative spot treatment charges and restricted concentrate availability. The physical picture is therefore tight but increasingly specific: low cathode availability and constrained concentrate supply, rather than evidence of an indiscriminate Chinese demand boom.
Aluminium
Aluminium produced the largest inventory move of the week. SMM primary aluminium-ingot social inventories fell 55,000 tonnes in the week to 24 September, following a 63,000-tonne draw the previous week. The cumulative 118,000-tonne two-week reduction is the steepest comparable pre-National Day draw in SMM's 2020–26 data.
Billet is considerably less tight. Social inventory stood at 149,000 tonnes on 24 September, and warehouse outbound volumes increased by 6,200 tonnes week on week to 45,100 tonnes during 15–21 September, but billet stocks remain 26,000 tonnes above last year and are the highest for this point of the year in three years.
There is, however, a new downstream improvement. Cast aluminium-alloy social inventory fell 2,700 tonnes to 31,800 tonnes, ending the six-week accumulation tracked in the previous two editions. It is the clearest sign this week that the improvement is beginning to extend beyond primary ingot.
Leading processor operating rates have also continued to improve, particularly for industrial profiles, while construction profiles remain weak, and primary aluminium-alloy producers are operating at around 60%. Temporary production interruptions affected rod supply in Guangxi and Yunnan, but most lasted only five to ten days and the majority of affected capacity has restarted.
The next test is National Day. SMM's 2020–25 data show primary aluminium-ingot inventories increasing 4.0–17.3% over the holiday and billet stocks rising 12.7–66.0%. A rebuild is normal; its magnitude will be more informative than its direction.
Zinc
Zinc continues to show severe upstream tightness alongside weak downstream demand.
SMM's imported zinc-concentrate treatment-charge index fell another $1.55/dmt to −$130.40/dmt, while domestic Zn50 concentrate TC remained around −RMB2,100 per metal tonne. Downstream conditions remain considerably weaker. SMM's latest galvanising survey puts operating rates at 53.39%, down 1.1 percentage points week on week, with producers largely taking delivery of previously purchased zinc rather than placing substantial new orders, and some businesses have already begun holiday shutdowns.
The SHFE/LME zinc ratio remains around 6.8, and China's zinc-ingot export window remains open. However, SMM reported on 21 September that profits from shipments to Southeast Asian delivery warehouses had narrowed sharply, so the arbitrage remains available but is less profitable than earlier in the move.
That distinction matters. Zinc concentrate remains exceptionally scarce, but downstream demand is weak and the incentive to move Chinese refined metal offshore is diminishing. The post-holiday inventory reading should help establish which force is dominating.
Lead
Lead has undergone a substantial pre-holiday inventory draw. Secondary-lead finished-product inventory fell to 8,000 tonnes on 24 September, down 4,400 tonnes from the previous comparable reading of 12,400 tonnes, as battery manufacturers accelerated rigid-demand purchasing while some smelters had limited spot availability. Primary lead inventories have also fallen to their lowest level in more than two and a half years, according to SMM.
The draw remains heavily influenced by National Day purchasing. Battery manufacturers have largely completed holiday procurement and spot premiums have begun falling, while around 60% of 25 secondary-lead smelters surveyed by SMM plan to maintain normal production through the holiday. A post-holiday inventory reversal is therefore plausible and will be the more useful test of underlying tightness.
Nickel
The Indonesian NPI disruption has yet to create physical scarcity in China. Water constraints at parts of the Indonesia Morowali Industrial Park have reduced output from affected RKEF lines by roughly 30–40% from previous loads, and a half-month disruption could affect around 50,000–70,000 tonnes of high-grade NPI product.
Chinese buffers remain substantial. Port inventories continue to rise, stainless-steel demand is weak and mills have been reluctant to undertake aggressive pre-holiday restocking. SMM 10–12% Chinese NPI was around $137.43 per nickel unit on 24 September, while imported Indonesian NPI delivered into China was around $137.82. Refined nickel remains similarly comfortable, with Jinchuan premiums easing and imported refined metal trading at almost no premium.
The production disruption is real; physical scarcity in China is not yet evident.
Tin
Tin's latest trade data show a significant improvement in raw-material availability. China imported 19,331.99 gross tonnes of tin ore and concentrate in August, up 14.0% month on month and 88.4% year on year. Myanmar supplied 7,395.46 tonnes, up 61.84% month on month and 253.55% year on year, while the Democratic Republic of Congo supplied 3,762.79 tonnes, up 46.49% month on month. These are gross ore tonnes rather than contained tin and should not be interpreted as equivalent increases in usable metal.
Constraints remain in Wa State because of the rainy season, explosives availability and restart approvals. Low treatment charges are also limiting smelters, with operating rates around 90% in Yunnan but only roughly 30% in Jiangxi.
August refined imports reached 2,746.85 tonnes, up 21.04% month on month, while exports increased to 2,202.10 tonnes, leaving China a net importer by roughly 545 tonnes and around 2,582 tonnes across January to August. Despite improving ore imports, SMM reports that Chinese refined-tin inventories remain low. Raw-material availability is improving faster than refined-metal availability.
What to Watch After National Day
The current board shows selective physical tightness rather than a broad Chinese metals-demand recovery.
The strongest developments this week are the 118,000-tonne two-week aluminium-ingot draw, the end of the six-week cast-alloy inventory build and the persistence of Guangdong copper premiums through the contract roll. Zinc concentrate has tightened further, but weak galvanising activity and a less profitable export arbitrage provide important counterweights.
The first meaningful post-National Day readings will be more informative. Aluminium inventories normally rebuild over the holiday; copper will lose the support of pre-holiday purchasing; and zinc enters the break with already weak downstream activity. If those markets remain unusually tight once those seasonal effects pass, the physical signal will be considerably stronger.
FAQ
Which Chinese metal changed most this week? Aluminium. Primary-ingot inventories have fallen 118,000 tonnes in two weeks, while cast aluminium-alloy inventory has finally ended a six-week accumulation.
Is copper still tight? Yes. Nationwide social inventory fell around 16,500 tonnes, largely because of south-China draws, while Guangdong high-quality cathode premiums held around RMB900/t through the contract roll.
Why are Shanghai copper inventories rising if national inventories are falling? Shanghai rose 2,400 tonnes and Jiangsu fell 2,400 tonnes, broadly cancelling one another. The majority of the national decline occurred elsewhere, particularly in south China.
Why isn't zinc simply bullish? Concentrate availability is exceptionally tight, but galvanising activity has weakened and the export arbitrage remains open at reduced profitability.
Is nickel becoming scarce because of Indonesia? Not yet. The production disruption is real, but Chinese inventories and weak stainless-steel demand continue to provide substantial buffers.
Is tin supply improving? Raw-material availability is improving sharply, but the increase in ore imports has not yet translated into comfortable refined-metal inventories.
Data and source note: Chinese physical-market data are from Shanghai Metals Market releases through 24–25 September 2026. Inventory series cover different products, geographical areas and methodologies and should not be aggregated unless explicitly stated. Tin ore and concentrate import figures are gross physical tonnes rather than contained tin. International ratios are included only where SMM uses them to explain Chinese trade or physical-market conditions.
Sources
- Shanghai Metals Market — Copper physical-market and inventory releases, September 2026
- Shanghai Metals Market — Aluminium ingot, billet and cast-alloy inventory releases, September 2026
- Shanghai Metals Market — Zinc concentrate, galvanising and export-arbitrage releases, September 2026
- Shanghai Metals Market — Lead inventory and secondary-lead releases, September 2026
- Shanghai Metals Market — Nickel and NPI physical-market releases, September 2026
- Shanghai Metals Market — Tin ore, refined-metal and inventory releases, September 2026
- Bloodstone Research — China Metals Intelligence — The Physical Signal Strengthens, September 2026
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