Copper's Violent Week: Record High, Then Sharp Reversal

September 14, 2026 – Copper markets saw extreme volatility last week. On September 10, LME copper hit a record $14,858.50/t, with Shanghai copper above 111,000 yuan/t. The next day, LME copper plunged 4.25% and COMEX fell nearly 5% — the biggest single-day drop since July 2025.

Why It Surged: No Copper Outside the US

The rally was driven by extreme inventory mismatch, not demand.

• Mine supply tight: Chile's H1 concentrate output fell 7%. Global major miners' H1 production dropped 4.6%. Copper concentrate TC/RCs have fallen to negative $200/t — smelters are effectively paying to secure raw material.

• LME stocks critical: LME copper inventory is only ~210,000t, with cancelled warrants above 50%. China's social inventory is just 85,000t.

• US hoarding: COMEX inventory exceeds 690,000t, about 70% of global visible stocks. Copper has been pulled into US warehouses, draining non-US markets.

Why It Crashed: Tariff Doubts

On September 11, Bloomberg reported the White House is hesitating on refined copper tariffs. This undermined the core logic of the rally — traders had stockpiled copper in the US specifically to avoid future duties. If tariffs are delayed or dropped, that metal could flow back into global markets.

Adding to the sell-off: US PPI came in hot, Fed rate-hike odds rose above 70%, the dollar strengthened, and technical indicators had been overbought for days (RSI above 70 since September 9). Profit-taking was inevitable.

What It Means for Magnet Wire

First, policy risk now outweighs supply and demand as the key price driver. The tariff decision is unresolved — any headline can trigger another violent move.

Second, non-US tightness has not actually eased. LME inventories remain near historic lows, and China's smelter output is expected to fall further in September. The crash was sentiment-driven; physical tightness persists.

Third, downstream demand is highly price-sensitive. Above 110,000 yuan/t, Chinese buyers are purchasing hand-to-mouth only. The "Golden September" restocking season may disappoint.

Bottom line: The copper supply story isn't over — but the tariff script can be rewritten at any moment.

Disclaimer: This analysis incorporates data from publicly available market sources. Please independently verify all data before making business decisions.