Greenhill & Co Inc
Jeffrey Buckalew, 45, head of Greenhill's North American advisory activities, was believed to have been on the plane together with his wife and two children.
Also on board was Rakesh Chawla, 36, a Greenhill financial services sector banker, the firm said.
New Jersey State police Trooper Christopher Kay said five people were confirmed dead, but could not comment on their identities as the investigation was continuing.
The single-engine Socata plane took off from New Jersey's Teterboro Airport and was headed for DeKalb Peachtree Airport near Atlanta, Federal Aviation Administration spokesman Jim Peters said.
The plane belonged to Buckalew, who joined Greenhill in 1996 from Salomon Brothers. He was an experienced pilot with a passion for flying, Greenhill said, adding it had no further information on the crash.
Before the crash, the plane made contact with an air traffic controller asking for permission to seek higher altitude, which it was granted, Peters said. Following this, the transmission became garbled and the plane fell off the radar, he added.
Jeff was one of the first employees of Greenhill. He and Rakesh were extraordinary professionals who were highly respected by colleagues and clients alike, Greenhill Chairman Robert Greenhill and Chief Executive Scott Bok said in a joint statement. They will be sorely missed and our sympathies go out to their families and friends.
(Reporting by Greg Roumeliotis in New York; Editing by John Wallace and Richard Chang)