NEW YORK » An investment banker at a Manhattan firm and his father were charged in court papers unsealed Thursday with using inside information to earn over $1 million illegally by trading in securities of five health care companies.

The charges including conspiracy and securities fraud were contained in a criminal complaint unsealed in Manhattan federal court against 34-year-old Sean Stewart and his 60-year-old father, Robert. Sean Stewart, a Manhattan resident, is a managing director at Perella Weinberg Partners LP.

Federal prosecutors, consistent with a policy that often leads them not to identify financial institutions when employees are arrested, did not identify the firm. But the firm said in a statement it was cooperating with prosecutors.

"Today’s charges against an employee of the firm alleging insider trading activity are unprecedented in our history," Perella Weinberg Partners said. "The described rogue behavior, if true, violates not just the law, but our principles, our culture and the strict policies and procedures we have in place to protect our clients."

The firm said Stewart was suspended. He surrendered in Middleton, Wisconsin, and it was not immediately clear whether he made an initial court appearance. He was scheduled to appear Monday in Manhattan federal court. His father, who lives in North Merrick on Long Island, was released on $500,000 bail in Manhattan. Their attorneys did not immediately return messages seeking comment.

In a news release, U.S. Attorney Preet Bharara said that in one instance, "the son’s tip to his father became a gift to himself when his father kicked back some of the proceeds of the insider trading to pay for his son’s wedding."

A 2011 newspaper wedding announcement said Sean Stewart married an associate at a Manhattan law firm. It said Stewart graduated from Yale University and his father worked in Manhattan as an independent financial consultant.

Prosecutors said Sean Stewart began tipping off his father about upcoming mergers and acquisitions while he worked as vice president in the health care investment banking group of a global bank headquartered in Manhattan in 2011, a few months before leaving for Perella Weinberg. Consistent with their policy, prosecutors did not identify that bank either.

Prosecutors said Robert Stewart and a cooperating witness did not speak directly about their trading over the phone or in email, but sometimes chose instead to use golf-related code language.

They said the father also tried to avoid detection by discussing trades only at face-to-face meetings and by sharing illegal proceeds in small increments of cash over time.

According to prosecutors, the father told the cooperating witness once that his son had chastised him for failing to make use of a tip, saying: "I can’t believe I handed you this on a silver platter and you didn’t invest in it."