Marble Ridge Capital accused Neiman Marcus of 'corrosive conduct' over a plan to transfer luxury online retailer MyTheresa to the department store’s private equity owners. NEW YORK, United States — Neiman Marcus is once again feeling the heat. On Monday, one of its creditors — distressed debt investor Marble Ridge Capital — delivered an urgent letter to to the department store group's board of directors, calling the company's plan to transfer ownership of e-commerce venture MyTheresa “corrosive conduct."