Copper prices headed for their biggest quarterly rise in ten years on Tuesday, as resurgent Chinese demand, supply disruption and massive global stimulus powered a rebound from four-year lows hit in March.

Benchmark copper on the London Metal Exchange (LME) was up 1% at $6,022 a tonne at 1116 GMT and up almost 22% in the last three months.

The metal used in power and construction is now just below its January high of $6,343, before the coronavirus spread worldwide.

Behind the gains are “supply fears driven by coronavirus spreading in major copper producing countries like Chile and Peru (and) the recovering economy, above all in China,” said Commerzbank analyst Daniel Briesemann.

A close above $6,000 could fuel further buying, but supply and demand fundamentals justify a level around $5,500 and prices will eventually fall, he said.

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STOCKS: On-warrant copper inventories in LME-registered warehouses fell by 1,200 tonnes to 111,650, the lowest since Jan 17.

Stocks in Shanghai Futures Exchange (ShFE) warehouses at 99,971 tonnes are the lowest since January 2019.

CHINA: Factory activity in China quickened in June, beating expectations. The total new orders index also brightened, but export orders continued to contract and factories cut jobs.

SUPPLY: Freeport Indonesia’s production of copper concentrate and copper ore were both below its initial targets this year. Chile’s mines minister warned last week the country’s output would be lower as the coronavirus spread.

POSITIONING: Speculators are betting on higher copper prices, with a net long on the LME equal to 3.6% of active contracts by Friday, the biggest since January, brokers Marex Spectron said.

OTHER METALS: LME aluminum was up 0.7% at $1,620.50 a tonne, zinc rose 0.5% to $2,072, nickel added 0.3% to $12,850, lead slipped 0.1% to $1,800.50 and tin was 0.5% higher at $16,850 – all up between 4% and 15% this quarter.