Law Firm Simpson Thacher Finalizes 916K-SF Lease at Extell’s 570 Fifth Avenue
The new lease is more than 200,000 square feet larger than the law firm's original deal
By Amanda Schiavo June 1, 2026 12:59 pm
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Global law firm Simpson Thacher & Bartlett has finalized the largest Manhattan office deal signed in May.
The law firm, which specializes in corporate transactions and private equity, signed a 916,000-square-foot lease at Extell Development’s office development at 570 Fifth Avenue, according to a memorandum of lease filed in property records and a new Manhattan office report from Colliers.
The new lease is more than 200,000 square feet larger than the law firm’s original deal. In September, Simpson Thacher was in talks to lease roughly 700,000 square feet at the Midtown skyscraper, Commercial Observer reported. The details of the change in square footage were unclear, but the lease memorandum noted an “execution of lease” date of May 8.
It is unclear when the law firm will move to 570 Fifth Avenue, as Extell’s planned office and retail building anchored by Scandinavian furniture giant Ikea is still under construction and has an expected delivery date of 2028. The law firm has a current address of 425 Lexington Avenue listed on its website.
CBRE represented Simpson Thacher in this deal. CBRE did not immediately respond to a request for comment.
Extell’s Gary Barnett signed the lease agreement for the developer, according to records, while Kelly Stevens, chief operating officer for Simpson Thacher, signed on behalf of the law firm. Spokespeople for Extell and Simpson Thacher did not immediately respond to requests for comment.
Once 570 Fifth Avenue is complete, the law firm’s space at the building will span 26 stories of the 29-story tower, almost certainly making it the property’s office anchor tenant. The tenant has the option to extend the lease term for two periods of 10 years, according to records.
The asking rent was not immediately available, but the average asking rent for office space in Midtown Manhattan was $84.15 per square foot in May, according to the Colliers data.
Amanda Schiavo can be reached at aschiavo@commercialobserver.com.
