The Financial Post reports in its Saturday edition that U.S. authorities have accused short-seller Andrew Left of committing fraud through stock trades, social media posts and research reports. A Bloomberg dispatch to the Post says the Securities and Exchange Commission on Friday alleged Mr. Left used his firm, Citron Research, to generate $20-million (U.S.) in profits from illegal trading involving almost two dozen companies. The Justice Department also announced a criminal case against Mr. Left, accusing him of securities fraud. The cases against Mr. Left stem from a wide-ranging U.S. effort to examine relationships between hedge funds and skeptical researchers. The probes have been rattling the industry for three years as investigators have sought information on dozens of money managers and activists. According to the SEC, Mr. Left would make recommendations about a stock, on which he had short or long positions, sometimes giving a target price at which he thought the stock would trade. The Justice Department said Mr. Left would create a false perception that his public comments on a stock were in line with his trading activity. According to the SEC, his misconduct included Roku, American Airlines and Nvidia.