Greenlight's Einhorn says cuts fund's long exposure in January -call NEW YORK (Reuters) - David Einhorn, chairman of reinsurer Greenlight Capital RE, said Wednesday that he has reduced his long positions in his investment portfolio and added to his short exposures. Einhorn, who also runs the $8 billion hedge fund Greenlight Capital, said on an earnings call for Greenlight Re that his investment fund lowered its net long exposure to 29 percent at the end of January from 39 percent at year-end. Einhorn added that the recent lawsuit against Standard & Poor's was "negative for the rating agencies" and that rating agency Moody's Corporation is "not immune." Reporting by Sam Forgione; Editing by James Dalgleish