The founder of Citron Research faces up to 25 years in prison after a U.S. federal jury found he used misleading social media posts and public commentary to manipulate stock prices tied to his trading positions. (Bloomberg)

Talking point: Left previously targeted Shopify with a series of bearish reports. In 2017, he accused the company of operating a “get-rich-quick scheme” akin to the multi-level marketing company Herbalife, prompting Shopify’s stock to fall more than 12 per cent. Shopify CEO Tobi Lütke fired back, calling Left a “short-selling troll.” Left has also taken aim at companies including Tesla, Nvidia, Meta and Canadian cannabis distributor Cronos. A 2018 Citron report on Cronos triggered a 30 per cent one-day drop in its stock price. The ruling is expected to reverberate across Wall Street’s activist-investing community, with legal experts and market observers warning it could make short sellers and other market commentators more cautious.