In 2014, global metals markets were jolted by a massive fraud centered on the Chinese port city of Qingdao. At the heart of the matter lay allegations that duplicate warehouse receipts had been used to post the same pile of metal as collateral for multiple loans from different banks. The fiasco forced Citi, Standard Chartered and Standard Bank to record hundreds of millions of dollars' worth of losses, and it unleashed a torrent of lawsuits that are still being sorted out today.

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