The California-based ride-hailing company would become the largest tenant in the hulking structure at 433 West Van Buren Street, which is in the midst of an $800 million overhaul, according to the Chicago Tribune.
An Uber spokesperson declined to confirm the lease negotiations to the Tribune.
If it signs the deal, Uber will join several other firms who have already committed to space in the 2.8 million-square-foot building formerly known as the Old Main Post Office.
Walgreens last year was the first company to announce a lease in the building, taking 200,000 square feet. Other confirmed tenants are ad agency AbelsonTaylor, Ferrara Candy and the Chicago Metropolitan Agency for Planning, which agreed to lease 49,000 square feet.
Two companies owned by the Kroger grocery store chain, Home Chef and data analytics firm 84.51, last month announced they’re taking a combined 132,000 square feet in the building.