Zinc TC Collapse Deepens: Treatment Charges at Multi-Year Lows as Concentrate Crunch Tightens Its Grip

The zinc concentrate market is tightening further, with treatment charges sliding to multi-year lows in both the domestic Chinese and seaborne markets. FocusEconomics, in its latest commodity overview, cites "limited raw material availability" as the primary driver, while SMM reports a "continuous decline in zinc concentrate TC" across Chinese spot markets. The TC compression is the direct result of a structural imbalance: mine supply growth has consistently underperformed expectations, while global smelter capacity — particularly in China — has continued to expand. (FACT: FocusEconomics; SMM/Metal.com)

LME inventories tell the story. Exchange-registered zinc stocks stand at approximately 156,000 tonnes, a level that appears comfortable only against the terrifying lows of 2023 but is historically tight. Critically, the net build since the start of 2026 is just 21,125 tonnes — a paltry increase compared with the enormous stock overhang of 400,000 tonnes that weighed on prices through much of 2024. The fact that inventories have barely risen despite bearish macro sentiment and a widely forecast surplus underscores the severity of the concentrate bottleneck. (FACT: LME data; Reuters, May 20, 2026)

The concentrate crunch explained. The TC collapse traces back to a multi-year under-investment in zinc mine capacity. After the price crash of 2023, several high-cost mines closed or deferred expansion, and new greenfield projects have been slow to reach commercial production. The ILZSG data for 2025 showed global mined output rising by 4.8% year-on-year after three consecutive years of decline, but that recovery has been uneven and insufficient to replenish depleted concentrate stocks. SMM notes that Chinese smelters, which account for roughly half of global refined zinc output, have been competing aggressively for seaborne concentrates, driving spot TCs in China below levels that cover full production costs. (FACT: SMM/Metal.com; ILZSG, April 2026)

Smelter margins under siege. The TC compression creates a perverse dynamic for zinc supply. At current TC levels, many smelters — particularly in Europe and China — are operating at or below breakeven on the smelting margin alone, relying on by-product credits (sulphuric acid, silver, germanium) to stay cash-positive. A sustained period of low TCs will inevitably trigger rationalisation: smelter closures, maintenance outages accelerated, or outright capacity idling. This creates a self-limiting mechanism whereby low TCs eventually reduce refined metal output, tightening physical availability and pushing LME prices higher — which in turn exacerbates the squeeze on consumers. (FACT: Fastmarkets; SMM/Metal.com)

The global distribution of the crunch is uneven. European smelters face the most adverse conditions — low TCs combined with high energy costs and carbon compliance expenses. Several European zinc smelters have already idled or reduced operating rates since 2024. Asian smelters, particularly in China and South Korea, have fared somewhat better due to lower energy costs and government support, but the continuous decline in domestic Chinese TCs is now testing breakeven levels there as well. (FACT: Reuters, May 20, 2026; Fastmarkets)

Price implications. The disconnect between concentrate market conditions and LME prices is narrowing. Zinc's year-to-date rally of approximately 13% has been driven primarily by supply concerns — the Kazzinc blast, the Cajamarquilla fire (now partially resolved), and the general TC malaise. But demand-side weakness in galvanizing and construction applications suggests that the price rally is running ahead of physical consumption fundamentals. If smelter margins deteriorate further and trigger output cuts, the LME price would need to rise higher still to equilibrate the refined metal market — a bull case that depends on demand not collapsing entirely. (FACT: Reuters, May 20, 2026; FocusEconomics)