Irving Kahn, who made his first stock trade in June 1929 — turning a tidy profit from the stock market crash four months later — and persevered for more than eight decades to become Wall Street's oldest living active professional investor, died this week at his home in Manhattan. He was 109.

His son Thomas confirmed his death.

A disciple and later partner of Benjamin Graham, the contrarian advocate of "value investing," Kahn would go on to work at Abraham & Co. and Lehman Bros., which he left in 1978 to open Kahn Bros. Group with two of his sons, Alan and Thomas. When he died, he was chairman of Kahn Bros., a privately owned investment advisory and brokerage firm, which manages $1 billion through its subsidiaries.

He also was the last surviving member of what had been described as the oldest living sibling quartet. Sister Lee Kahn died in 2005 at 101. Sister Helen Reichert was nearly 110 when she died in 2011. Brother Peter Keane died last year after turning 103.

Until late last year, Kahn was still commuting by taxi to his Midtown office from his Upper East Side apartment three days a week.

Kahn continued to devour newspapers and magazines until a few hours before he died. His grandson Andrew had been reading an Economist cover article to him on Vladimir Putin.

Thomas Kahn, who is 72 and president of Kahn Bros. Group, said that studies of centenarians, including his father, by Dr. Nir Barzilai at the Institute for Aging Research at the Albert Einstein College of Medicine in the Bronx conclude that the secret to longevity is a mix of DNA, healthy living and luck.

"My father smoked until he was 50, and he didn't watch what he ate," Thomas Kahn said. "So the preponderance of his case was DNA and luck."

He said he received an e-mail from Barzilai the other day suggesting that his father will remain forever young. "Irving's not dead," the doctor said, "because we have his cells and his DNA, and they're working every day in our laboratory."

Dori J. Maynard, a journalist at the forefront of the campaign to make the American news media a more accurate mirror of American diversity, died Tuesday at her home in Oakland, Calif. She was 56.

The cause was lung cancer, said her mother, Liz Rosen.

Maynard was the president and chief executive of the Robert C. Maynard Institute for Journalism Education, a nonprofit organization based in Oakland. There, she continued her lifelong interest in exploring the often rocky landscape where race, class, ethnicity and the news media converge.

The journalism institute is named for her father, a former editor and publisher of the Oakland Tribune. Among his accomplishments, Robert Maynard was the first black person in the United States to own a general-circulation daily newspaper.