Platts Australian alumina assessment closed the week at $310.50/mt FOB, decreasing $1.50/mt from Thursday, weighed by sluggish demand, the higher cost of credit in China, and concerns relating to counter-party risk. The assessment was down $1.75/mt on the week, and $10.50/mt on the month.

Bid, ask levels centered $309-312/mt FOB Australia.

A trade financing probe at China's Qingdao port has spooked market participants, raising the cost of borrowing from local and offshore banks, and prompting certain prospective Chinese alumina importers to step back.

At the same time, a few sellers may be experiencing pressure to offload tons before the northern summer holiday season takes participants out of the market in July and August.