Chinese state-owned commodities house Citic Resources has announced that over half of its alumina stock at Qingdao Port is missing, as the investigation into the alleged metals financing fraud continues.

In a statement issued to the Hong Kong Stock Exchange, Citic said it "has been unable to sequester about 123,446 megatons of alumina which the group has stored at Qingdao Port". In total, the group had held 223,270 megatons in Qingdao.

The investigation continues, as authorities attempt to establish whether traders used single instances of metals cargoes to secure multiple bank loans, with HSBC this week becoming the latest financial institution to increase its vigilance of Qingdao activities.

Commodity prices have bombed on the continued probe – billed the "commodity Ponzi probe" by influential financial website Zero Hedge, which also suggests that "the day when the commodity funding deals finally end is fast approaching".

"There's been a reaction in those metals that have high exposure to collateral financing, for instance copper is highly concentrated in those financing deals, also iron and aluminium, Casper Burgering, a senior metals economist at ABN Amro told IBTimes UK. He said that as investigations intensify, he expects jitters to increase and "price volatility for copper, aluminium and iron ore".

Citi and Standard Chartered have already confirmed they will investigate whether loans they disbursed were pledged against stocks that have been collateralised more than once.

Qingdao-based trader Decheng Mining is believed to be at the centre of the investigation, however authorities have yet to confirm the identity of the "whale".