The country's biggest apartment developer, Chicago-based Equity Residential, has filed preliminary paperwork with the city for a 5-story, 275-unit complex on a half-block site in South Lake Union.

The property, on Minor Avenue North between John and Thomas streets, is owned by Seattle developer Touchstone. It put the site on the market earlier this year and a sale is pending, according to the Commercial Brokers Association database.

The city's Queen Anne/Magnolia Design Review Board is tentatively scheduled to consider Equity's project Jan. 4.