"We sold Macy's for a loss after the company announced a significant reduction in full-year 2016 guidance," Einhorn said in a letter seen by Reuters. Macy's and Apple .O> were "material losers" for the firm as it lost 2.6 percent in the second quarter, the letter said.

Greenlight sold Macy's at $32.08 a share after having told investors in January that it had bought the stock at $45.69.

(Reporting by Svea Herbst-Bayliss; Editing by Jeffrey Benkoe)