Gary Barnett’s Extell Development has filed plans for a 32-story, 875,720-square-foot office tower at 574 Fifth Avenue in Manhattan’s Diamond District. The building will feature offices and nearly 98,000 square feet of retail space. Extell is partnering with Ingka Investments, which will own 80,000 square feet of retail and hold a one-third stake in the project. Initially, Barnett envisioned a 78-story, 1.1 million-square-foot supertall at the site, with mixed-use options including residential, hotel, or office space. Extell recently secured a $340 million refinancing deal with IGIS Asset Management for the development.