An army of South Korean retail traders has sparked a nine-fold rise in the shares of a battery materials producer as it takes on hedge funds betting against the company’s stock.

The individual investors — known locally as “ants” — have bought a net Won3.1tn ($2.45bn) of shares in EcoPro and its subsidiary, cathode producer EcoPro BM, in an episode with echoes of the US “meme stock” craze, where small traders used platforms such as Reddit to whip up enthusiasm for previously unloved stocks.

EcoPro’s rally of 833 per cent this year has come as bigger investors ramp up their short positions, or bets that the stock will fall. Short positions in EcoPro shares have surged from Won54bn at the beginning of the year to Won1.3tn, according to data from Korea Exchange. EcoPro BM shares have gained about 200 per cent year to date.