Reuters reported that shares in Aluminum Corp of China Ltd dived by 8% t to their lowest since March as investors fled on fears of mounting costs including for electricity and dwindling margins.

Analysts this week called attention to soaring production costs, particularly for alumina Chalco's main product and falling prices as supply swells. The surprise move raised the possibility that other provinces would follow suit in relaxing state set electricity prices.

According to the report Chalco shares dived nearly 8% its biggest percentage loss since January 22nd to a low of HKD 10.88 before bouncing back to stand 6.9% lower at midday, underperforming a slightly weak market.

Investment bank CICC's Shenwei Ding said "China's alumina refineries could see their gross margins further squeezed by surging bauxite import prices, ocean freight rates, coal prices and other input prices."