Chicago developer Sterling Bay reportedly is poised to purchase the bulk of the office and parking space at 875 N. Michigan Ave., the iconic skyscraper better known to Chicagoans as the John Hancock Center.

Sterling Bay and an unnamed partner reached a deal to buy the space from a group led by the developer Hearn for more than $300 million, Crain’s Chicago Business reported Thursday afternoon.

The deal includes 900,000 square feet of office space on floors 13 to 41, and 700 parking spaces from floors 4 to 12, according to Crain’s.

Representatives for the developers did not immediately return messages seeking comment.

Condominiums, retail space, the 360 Chicago Observatory and the television and radio antennae on the building’s trademark antennas have numerous separate owners.

Perhaps the most recognizable figure on the Chicago skyline besides the Willis Tower, the building dropped its John Hancock title in February at the request of Manulife Financial, the insurance giant that acquired John Hancock Financial in 2004.

The 1,128-foot building — the city’s fourth tallest — officially goes by its address at 875 N. Michigan Ave. — at least until a long-term naming rights deal is reached.

It had been known as the John Hancock Center since it was completed in 1968, when its 100 stories were enough to make it the second-tallest building in the world.