The 30-year-old son of a hedge fund founder has been charged with second-degree murder in the killing of his 70-year-old father.
Thomas Gilbert Jr was also charged with criminal possession of a weapon and criminal possession of forgery devices.
Thomas Gilbert Sr was shot in the head in his New York apartment after the two argued over the son's allowance, police said.
The son went to his parents' home on Manhattan's East Side on Sunday and asked his mother to go out to get him some food, according to police. About 15 minutes later, she got a "bad feeling" and went back, said Robert Boyce, New York Police Department's chief of detectives.
"She found (Gilbert) Senior on the floor with a bullet hole in the head," Mr Boyce said. "She also found a gun resting on his chest with his left hand covering it."
But Mr Boyce said it was a staged suicide - his son was trying to cover up the killing.
Gilbert Jr was in debt and had argued with his father over his allowance, police said.
A lawyer for the younger Gilbert did not immediately return a call for comment. His next court appearance was set for Friday.
According to the criminal complaint, Mr Gilbert Sr was found dead on the floor near the window of a bedroom. A .40-calibre Glock firearm was loaded with an additional live round, it said.
Authorities found more ammunition at the defendant's apartment, including two magazines loaded with a total of 17 rounds, loose bullets and empty shell casings, the complaint said. A skimmer device and 21 blank credit cards were also found.
In 2011, Mr Gilbert Sr, a graduate of Princeton University and Harvard Business School, founded Wainscott Capital Partners Fund, which has 200 million dollars (£131 million) in assets.
Gilbert Jr also attended Princeton, graduating in 2009 with a degree in economics. Authorities said he had no recent work history.
Mr Gilbert Sr worked on Wall Street for more than 40 years, according to his profile on Wainscott's website, and he previously co-founded Syzygy Therapeutics, a biotech asset acquisition fund. He was also founder and CEO of an online teacher education company called Knowledge Delivery Systems.
Wainscott, which invests in biotechnology and healthcare stocks, had no comment.
The shooting was a rare act of violence in the Sutton Place neighbourhood, a wealthy enclave just north of the United Nations.
Neighbour Pierre Gazarian remembered Mr Gilbert Sr as "incredibly courteous, elegant", and praised his "civility (and) caring".