Shares in China’s lithium producers fell sharply on Tuesday after two of the largest miners warned that battery-metal woes had weighed on earnings for the first half of the year.

Tianqi Lithium Corp. forecast a negligible net income of up to 155-million yuan ($21.6-million) for the first six months, while Ganfeng Lithium Group Co. predicted a net loss of 300-million yuan to 550-million yuan for the same period. Chengxin Lithium Group Co. said its net loss could be as high as 850-million yuan.

The three producers, commenting in preliminary statements released late on Monday, cited lower lithium sale prices from January through June. Chengxin’s stock slid as much as 5.1% in Shenzhen. In Hong Kong, Ganfeng’s stock fell as steeply as 6.8% in morning trade, while Tianqi slid 3.3%.

Ganfeng said in a statement that the fall in prices of lithium salt and lithium battery products hit operating earnings “by a certain extent”, despite an orderly ramp up of battery capacity and an increase in sales. The company also said it had written down the value of assets including inventories, but provided no detail. Chengxin said it expected to take a 418 million yuan impairment on its inventory.

In better news, Tianqi said that it had made progress in digesting existing lithium concentrate inventory, meaning the cost of concentrates was now approaching procurement prices. The company also expects an increase in investment income from miner Sociedad Química y Minera de Chile, after projecting an year-on-year increase in SQM’s performance in the first half.

Still, even after two consecutive years of losses, spot lithium carbonate prices in China retreated by almost another fifth in the first half, battering an industry that has struggled with a supply glut and slower-than-expected electric-vehicle sales. Domestic prices have seen some signs of recovery in recent weeks, thanks to Beijing’s pledge to regulate “disorderly” price competition in oversupplied sectors.

The companies are due to report full reports for the six months in August.