Meet Julia Flesher Koch, the billionaire philanthropist who's one of the world's richest women

Julia Flesher Koch pictured in 2018. Patrick McMullan/Patrick McMullan via Getty Images Julia Flesher Koch, the widow of billionaire industrialist David Koch, is one of the richest women in the world.Forbes estimated that Koch and her family were worth $84.6 billion in 2026, making her the third-richest woman in the world.She inherited her fortune from her husband, David Koch, who died at age 79. At the time, Forbes ranked him among the 20 richest people in the world.Flesher Koch is now a philanthropist and has more recently ventured into sports ownership. Here's a look at Flesher Koch's life, real estate, and finances. Julia Flesher Koch's billionaire husband died in August 2019. Julia Flesher Koch was married to David Koch for 23 years. Getty Images/Chance Yeh/FilmMagic At the time of his death, David Koch was worth $42.5 billion, according to a Forbes estimate, making him one of the richest people in the world.They were married for 23 years. After her husband's death, Flesher Koch became one of the world's richest women. Julia Flesher Koch and David Koch in 2017. Dia Dipasupil/Getty Images for Lincoln Center Forbes pegged Flesher Koch's net worth at $84.6 billion as of October 7, 2026. This makes her the third richest woman in the world, after Alice Walton and Françoise Bettencourt Meyers.Alongside her children, Flesher Koch inherited a 42% stake in Koch, Inc. after her husband's death in 2019. Born in Iowa, Flesher Koch moved to New York in 1984 and became part of the high society scene. Julia Flesher attends the Costume Institute Exhibition Opening at the Metropolitan Museum of Art on December 9, 1991. Ron Galella, Ltd./Ron Galella Collection via Getty Images In the early 1990s, she was photographed at high-profile events, including the opening of the Metropolitan Museum of Art's Costume Institute Exhibition.She worked as an assistant to Adolfo, a fashion designer. Flesher Koch met David Koch on a blind date set up by friends in January 1991. David H. Koch and Julia Flesher at a charity benefit on May 23, 1995 in New York City. Ron Galella, Ltd./Ron Galella Collection via Getty Images However, they didn't hit it off immediately, according to The New York Times."Afterward, we shook hands, and I said, 'I'm glad I met that man because now I know I never want to go out with him,''' Flesher Koch told the Times in 1998.Six months later, they met again and started dating. After five years of dating, they were married in May 1996 at Koch's home in the Hamptons. David Koch and Julia Flesher Koch at the International Fine Art and Antique Dealers Show on October 10, 1996, in New York City. Ron Galella/Ron Galella Collection via Getty Images After their marriage, Flesher Koch became a fixture on the New York social scene, according to a 1998 profile in The New York Times. In 1997, Vogue editor picked Flesher Koch to serve as co-chairwoman for that year's Met Gala. Julia Flesher Koch in 1996 Ron Galella/Ron Galella Collection via Getty Images "Julia's one of those people who occur in New York every few years," fashion editor Patrick McCarthy told the Times in 1998. "She's beautiful, she loves fashion, she knows how to entertain, she's married to an extraordinarily rich man." The New York couple had three children together: David Jr., Mary Julia, and John Mark. Julia Koch (right), and two of her children, Mary Julia Koch and David Koch Jr., in 2024. Jared Siskin/Patrick McMullan via Getty Images Mary Julia Koch works as an associate editor of Free Expression, a daily opinion newsletter by The Wall Street Journal.David Jr. Koch is the special assistant to the general manager of the Brooklyn Nets, according to his LinkedIn page.John Koch, the youngest of the three siblings, keeps a lower public profile. BSE Global described him as high-school-aged when it announced the family's investment in 2024. Flesher Koch and her husband owned at least $143 million in real estate in New York City, the Hamptons, Aspen, and Florida at the time of his death. A Fifth Avenue intersection in New York. Smith Collection/Gado/Getty Images Business Insider estimated in 2019 that David Koch's known real-estate holdings were worth at least $143 million, based on purchase prices and then-current property estimates.For years, they lived in a Fifth Avenue apartment once owned by former first lady Jacqueline Kennedy Onassis that Koch bought in 1995 for $9.5 million, according to The New York Times. In 2004, the couple's primary residence became a massive 18-room duplex in a ritzy Manhattan building. The duplex at 740 Park Avenue. STAN HONDA/AFP via Getty Images Koch paid about $18 million for the duplex at 740 Park Avenue in 2004, according to The Real Deal.740 Park Avenue is notoriously exclusive and expensive. To live in the Art Deco co-op, which opened in the 1930s, Business Insider reported in 2017 that at the time prospective buyers reportedly needed at least $100 million in liquid assets.Flesher Koch sold the duplex in 2025 for $45 million, The Wall Street Journal reported, citing property records. The couple also owned a $40.25 million Manhattan townhouse. A row of townhouses in the Upper East Side neighborhood of New York (not the property in question). Richard Levine/Corbis via Getty Images Sources told the New York Post in August 2018 that Koch and Flesher Koch paid cash for the property.The eight-bedroom Upper East Side home, which was originally listed for $51 million, included a 1,500-square-foot primary suite, a gym, and a rooftop terrace.The Wall Street Journal reported that Flesher Koch sold the property for $41 million in an off-market deal in 2023. Flesher Koch bought two Upper East Side apartments in 2022 worth $101 million. The two apartments were part of Microsoft cofounder Paul Allen's estate. Dave M. Benett/Getty Images In 2022, Flesher Koch bought two apartments at 4 East 66th Street from the estate of Microsoft cofounder Paul Allen for a combined $101 million, The Real Deal reported.At the time, The Real Deal reported that this was the most expensive co-op sale in New York's history. Flesher Koch also owns two neighboring oceanfront properties on Meadow Lane in the Hamptons. Oceanfront homes in Southampton. Getty Images/Kirkikis One is the longtime mansion she has owned since the 1990s; in 2021, she bought the adjoining oceanfront estate for $70 million, The Wall Street Journal reported.In 2025, she expanded her holdings again, paying $33.5 million for a property on the bayfront, according to property records cited by the Journal. The Kochs also had homes in Aspen and Palm Beach. Palm Beach in Florida. Bloomberg/Getty Images David Koch bought two neighboring Aspen properties in 1989 and 1991 for $1.9 million and $1.75 million, respectively, according to Pitkin County property records previously reviewed by Business Insider.Julia Koch still has a residence in Palm Beach. The Wall Street Journal reported in 2026 that she was the wealthiest property owner in the town. Flesher Koch is the president of the David H. Koch Foundation, which funds science and medical research, education, and the arts. Julia M. Flesher Koch attends the 2012 New York City Ballet fall gala at David H. Koch Theater, Lincoln Center. Getty Images/Charles Eshelman/FilmMagic Through the David H. Koch Charitable Foundation and personal giving, the couple had donated more than $1.3 billion, according to the Julia Koch Family Foundation website.Flesher Koch remains president of the David H. Koch Foundation, according to its latest tax filing for 2024. She sits on the boards of Koch, Inc., Memorial Sloan Kettering Cancer Center, The Metropolitan Museum of Art, and Venetian Heritage. Julia Flesher Koch and Home Depot cofounder Ken Langone at the BCNY Annual Luncheon in 2025. Sylvain Gaboury/Patrick McMullan via Getty Images Flesher Koch has also donated to NYU and NYU Langone Health. She gave $3 million to establish an endowed professorship in orthopedic surgery and $1.4 million to create an endowed scholarship that covers the full tuition of at least one medical student at a time. In 2023, Flesher Koch set up the Julia Koch Family Foundation. Julia Koch pictured in Miami in 2025. 305pics/GC Images Julia Koch is the founder and chair of the foundation. The foundation has committed $75 million to an NYU Langone ambulatory-care center in West Palm Beach, pledged $50 million to The Metropolitan Museum of Art, and made grants to several Brooklyn nonprofits." In 2024, Julia Koch and her children purchased a 15% stake in BSE Global. The Barclays Center is the home stadium for the Brooklyn Nets. Photo Italia LLC/Getty Images BSE Global owns the Brooklyn Nets, New York Liberty, and the Barclays Center. Forbes reported that the deal was worth almost $700 million. In 2025, Flesher Koch and her children acquired 10% of the NFL's New York Giants. Deonte Banks of the New York Giants celebrates after the game against the Arizona Cardinals at MetLife Stadium in October 2026. Al Bello/Getty Images The deal valued the team at over $10 billion, according to Forbes."My family and I are honored to join the Giants organization, a storied franchise with deep roots in New York," Julia Flesher Koch said in a New York Giants press release announcing the deal. Read next Roya is a reporter on Business Insider's Editorial Partnerships team. She is based in London. Before joining Business Insider, she worked as a reporter at financial newswire Alliance News and was an intern at The Wall Street Journal. Roya graduated from City St George's, University of London with an MA in International Journalism. Katie was a senior reporter on Business Insider's Features team, based in New York City. 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