The law firm of Rosenberg & Estis is expanding at 733 Third Ave. to 51,778 square feet. The lawyers renewed their entire 12th and 14th floors and signed a new, 10-year lease for the entire 15th floor of 16,456 square feet.

The firm also enjoys a 2,009-square-foot terrace overlooking Third Avenue.

Rosenberg & Estis was represented by its members, Michael E. Lefkowitz and William Byers. The Durst Organization ownership was represented by Tom Bow and Ashley Mays.

Founded in 1975, Rosenberg & Estis is focused on real estate. It moved to the building in 1993, when it occupied just the 14th floor.

This year, the building was certified “LEED Gold,” and the Energy Star-certified tower ranks in the top 20 percent of the most energy efficient in the US.