Adds details on outlook, results, background Feb 10 (Reuters) - Newell Brands Inc NWL.O said its top boss Ravi Saligram will retire effective May 16 and forecast annual results below analysts' estimates, sending the Sharpie maker's shares down 11% in premarket trading. Newell has been grappling with a rise in costs that has hammered its profits amid an inflation-induced slowdown in consumer spending. "The business continued to be impacted by a tough operating environment, including slowing consumer demand for general merchandise categories, as well as inventory reductions at retail," Saligram said.