Sidley, one of Chicago’s largest law firms, has agreed to occupy more than half of a proposed 45-story West Loop tower at 725 W. Randolph St., a deal that developer Related Midwest says will enable construction of the first new downtown office skyscraper in years.
From Apartment Complex to Office Tower
Related Midwest first proposed a combined apartment and hotel complex at the site before switching to an office building in 2023. The firm still needs City Council approval before breaking ground. Financial institutions typically require anchor tenants before funding office skyscraper construction, and the Sidley agreement — covering more than 500,000 square feet — should secure the necessary financing. Completion is targeted for late 2030, according to the Chicago Tribune.
Brian Fahrney, chair of Sidley’s executive committee, said the firm expected downtown’s high vacancy rates would yield plenty of options, but “for the type of space we were looking for, there were surprisingly few options.” Other tenants had already claimed the best available trophy spaces.
Vacancy Reality Check
The vacancy rate for Class A properties was at a record 21.3% earlier this year, according to Colliers, while Class B buildings stood above 30%. Yet demand for premium space in the West Loop — Chicago’s premier submarket — remains strong enough to support new construction. Fulton St. Cos. completed a smaller 11-story, 400,000-square-foot mixed-use project at 919 W. Fulton St. in early 2026.
Related Midwest’s Broader Portfolio
The developer is simultaneously working on The 78 — the new home of the Chicago Fire’s 22,000-seat soccer stadium — plus a 72-story apartment tower at 400 N. Lake Shore Dr. and a new quantum computing campus on the South Side. Sidley will relocate more than 1,500 employees from 1 S. Dearborn St. in the Central Loop, where it has been based since 2005. Fahrney cited the West Loop’s proximity to transit, restaurants, and hotels, noting that “a lot of our talent lives over there.”
The Sidley deal also signals that demand for premium office space in the West Loop remains resilient despite the broader market weakness. The submarket’s proximity to transit — including Ogilvie Transportation Center and Union Station — plus its density of restaurants and residential options has made it the preferred location for professional services firms seeking modern amenities. Real estate analysts say that if Related Midwest successfully finances and breaks ground on 725 W. Randolph, it could unlock additional office tower proposals currently stalled by the financing gap between vacancy rates and construction costs.
