NEW YORK - Mark Haines, 65, the coanchor of CNBC's morning Squawk on the Street show and one of the business news network's most recognized faces, died unexpectedly Tuesday evening at his home, the network said. It did not specify the cause of death.

Mr. Haines, a onetime anchor for Philadelphia's KYW-TV, worked at CNBC for 22 years. He was founding anchor of the Squawk Box morning show. In 2005, he started coanchoring Squawk in the Morning from 9 to 11 a.m. with Erin Burnett, while Squawk Box was pushed to an earlier slot. Burnett recently left CNBC for CNN.

"He was a very dear friend, and a ferocious and fearless questioner," she told CNBC Wednesday.

CNBC president Mark Hoffman said Mr. Haines was "always the unflappable pro."

Traders on the floor of the New York Stock Exchange observed a spontaneous moment of silence when they learned of his death, NYSE spokesman Richard Adamonis said. The exchange called him "an outstanding professional and pioneer in business journalism."

Mr. Haines is also remembered for calling a bottom to the stock-market decline on March 10, 2009, his first call of the recession. The Dow Jones industrial average never closed below its level of March 9.

Barry Ritholtz, head of the research firm Fusion IQ and a frequent guest on CNBC, said the biggest complaint about CNBC in the 1990s was that its anchors cheered on the stock-market bubble. The exception, he said, was Mr. Haines, who was always skeptical.

"He was trained as an attorney," Ritholtz said. "He brought that keen lawyer's eye to everything he did. It wasn't something often seen in the financial media."

Mr. Haines earned a law degree from the University of Pennsylvania and was a member of the New Jersey State Bar Association, CNBC said.

He worked at KYW-TV from 1984 to 1985. He had also worked as a news anchor at WABC-TV in New York and WPRI-TV in Providence, R.I. He joined CNBC in 1989.

Mr. Haines is survived by his wife, Cindy Voron Haines; a son, Matt; and a daughter, Meredith.

CNBC, which is owned by Comcast Corp., said funeral arrangements had yet to be made.