Activist hedge fund manager Dan Loeb is another all star that struggled big time in 2018.: His firm Third Point lost about 6 percent in December alone, bringing its yearly loss to about 11 percent, according to figures obtained by CNBC's Leslie Picker. Loeb is not alone in losing big money last year. Billionaire manager David Einhorn had a tougher year, with his main hedge fund losing 34 percent in 2018, the worst performance since Einhorn started the firm in 1996.