The People's Bank of China is injecting 250 billion yuan ($37 billion) through seven-day reverse bond repurchase agreements and 150 billion yuan through 28-day reverse repos, traders said.
Shanghai copper has flipped into backwardation amid a promise of value-added tax (VAT) cuts in China, which has increased near-term demand for physical copper, brokerage Jinrui Futures said in a note.
The tax reductions are not expected to be formalised until March but Jinrui Futures said their implementation could result in a 400 yuan a tonne boost to the ShFE copper price for every percentage point VAT decrease.
Prices at the close showed a 10 yuan a tonne backwardation between the March and April ShFE copper contracts and a 120 yuan a tonne backwardation from April to May.
FUNDAMENTALS
* COPPER: Three-month copper on the London Metal Exchange was up 0.2 percent at $5,979 a tonne, as of 0709 GMT, while the most-traded March contract on the Shanghai Futures
Exchange closed 0.5 percent firmer at 47,380 yuan ($7,003.28) a tonne.
* ZINC: The metal used to galvanise steel rose as much as 1.8 percent in Shanghai to 20,960 yuan a tonne, its highest since Dec. 12 before closing at 20,885 yuan, while LME zinc was up 0.1 percent to $2,500 a tonne after touching a one-week high.
"Spec positioning is largely flat now on our estimates on both LME and ShFE" zinc, Marex Spectron said in a note.
* ALUMINIUM: Aluminium led the rest of the LME complex lower, falling 0.6 percent to $1,849.50 a tonne after the U.S. Senate on Wednesday rejected legislation to keep sanctions on companies linked to Russian oligarch Oleg Deripaska, including aluminium firm Rusal.
* ALCOA: Top U.S. aluminum producer Alcoa Corp beat Wall Street estimates for quarterly profit on Wednesday, buoyed by strength in its alumina segment, but shares slipped after the company did not provide a closely watched profit measure for the full year.
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MARKETS NEWS
* Asian stocks nudged higher on Thursday after see-sawing through a subdued session on concerns over China's economic outlook, while an anti-climactic end to the latest chapter in the Brexit saga offered sterling a moment's peace.