NEW YORK — The parent company of Saks Fifth Avenue has signed a deal to buy upscale rival Neiman Marcus Group, which owns Neiman Marcus and Bergdorf Goodman stores, for $2.65 billion, with online behemoth Amazon holding a minority stake. The new entity would be called Saks Global, which will comprise the Saks Fifth Avenue and Saks OFF 5TH brands, Neiman Marcus and Bergdorf Goodman, as well as the real estate assets of Neiman Marcus Group and HBC, a holding company that purchased Saks in 2013.