SL Green, the city’s biggest commercial real estate landlord announced its founder and chairman, Stephen Green, is stepping down.

The firm’s CEO, Marc Holliday, will become chairman in January. SL Green made the announcement in a filing with the Securities and Exchange Commission Monday, Commercial Observer reports.

Green will remain as chairman emeritus, but he will no longer oversee the firm’s “long-term strategic direction,” SL Green said. He founded SL Green's predecessor, SL Green Properties, in 1980 before leading the company through an initial public offering in 1997.

Green is 80 years old, and has served as chairman since the IPO. Holliday joined the company in 1998, and has held the position of CEO since 2004. He was also previously the firm’s president, a role now held by Andrew Mathias.

In total, SL Green has interest in 119 Manhattan buildings spanning almost 50M SF, according to its website. Earlier this month, the firm entered into a contract with partner Ivanhoé Cambridge to sell their office condominium at 1745 Broadway to an Invesco-advised buyer for $633M.

On its first-quarter earnings call this month, the REIT's representatives said it is on track to fill more than a third of the office space at One Vanderbilt, its supertall office development in Midtown East. Last week, law firm McDermott, Will & Emory signed up for 106K SF in the building.