CHICAGO--The law firm Dentons has announced that it will extend its lease in Willis Tower, formerly known as the Sears Tower, here for 15 years.

The law firm, formerly known as Sonnenschein and most recently SNR Denton, will relocate to 144,000 sq. ft. in the city's tallest tower. The company did not announce where it is moving to in the building, but the firm reportedly has about 177,000 sq. ft. in upper floors. Dentons will remain in its current space in the building until the new space is completely built out, according to Mike Kazmierczak, senior vice president of leasing for U.S. Equities Asset Management, which manages leasing at the tower.

The 4.5-million-sq.-ft. tower is home to more than 100 different companies, including the global headquarters of United Airlines.

“Willis Tower meets the technology, infrastructure and location needs of our global law firm,” said Mary G. Wilson, managing partner of the Chicago office of Dentons, in a statement. “We evaluated dozens of alternatives and concluded that reinventing our physical space within Willis Tower will best meet the needs of our professionals and clients.” 

Kazmierczak, Derek Rolison and Bob Wislow with U.S. Equities represented Willis Tower on behalf of the building’s ownership, 233 S. Wacker Drive LLC, during the transaction. Dentons was represented by  Stuart Eisenkraft, Andrew Sussman, Lewis Miller, Patrick Nelson, Paul Stimpfle, Todd Lippman and Lisa Konieczka with CBRE.