David Einhorn’s hedge fund bucked last month’s equity-market slump, posting a 5.7% gain as competitors including Dan Loeb’s Third Point slipped. The advance brings Greenlight Capital’s increase for the year to 20%, according to a person familiar with the matter who asked not to be identified discussing private information. August was more muted at Third Point, where the main fund fell 0.2% in August and is down 20% for the year, according to an investor letter seen by Bloomberg. Greenlight’s results also far outstripped the S&P 500, which ended August down more than 4%.