American businessman, philanthropist, political activist, and chemical engineer, David Hamilton Koch, had a net worth of $50.5 billion at the time of his death. He was best known as co-owner (with older brother Charles), and an executive vice president of Koch Industries, a conglomerate that is the second-largest privately held company by revenue (with more than $100 billion in sales) in the United States according to a 2010 Forbes survey. Koch was the second-richest resident of New York City in 2010. David and his brothers Charles, Frederick, and William inherited Koch Industries from their father after his death. Their father, Fred C. Koch (d. 1967), invented the method of turning heavy oil into gasoline. Today the company, in which David had 42% stakes which have now passed to his wife Julia Flescher Koch, has investments in pipelines, refineries, fertilizer, fibers and polymers, forest and consumer products, chemical technology.

He was a major patron of the arts; a funder of conservative and libertarian political causes, including some organizations within the American Tea Party movement. Among other charities, he has contributed to Lincoln Center, Sloan Kettering, a fertility clinic at New York-Presbyterian Hospital, and the American Museum of Natural History's David H. Koch Dinosaur Wing.

Born in Wichita, Kansas in the United States, Koch's parents were Mary Clementine and Fred Chase Koch. His paternal grandfather was a Dutch immigrant who was a founding shareholder of the Quanah, Acme, and Pacific Railway. Koch went to school at the Deerfield Academy in Massachusetts, graduating in 1959 and moving on to the Massachusetts Institute of Technology (MIT). He left MIT in 1963 with both a bachelor's and a master's degree in chemical engineering.

In 1970 he joined the family firm Koch Industries, founding the company's New York office. In 1979 he became president of his own division, Koch Engineering. In 1983 Charles and David bought out their brothers Frederick and Bill for $1.1 billion following a complex and acrimonious legal battle, making Charles and David the majority owners of the company. The case was not completely settled until 2001 when Bill accused the company of taking oil illegally and Koch Industries settled for $25 million.

David Koch was heavily involved in conservative politics. He was the Libertarian Party's vice-presidential candidate in the 1980 election, alongside Ed Clark. Their campaign gained 1% of the nationwide vote - a good result for the Libertarian Party compared to other election years. Koch left the Libertarian Party in 1984 after it began supporting the elimination of all taxes. After this, he donated to various political campaigns, the majority of which were Republican, including putting $100 million behind a failed bid to oppose the re-election of Barack Obama in 2012.

In 2006 Koch founded the David H. Koch Charitable Foundation. He was a trustee of the American Ballet Theatre, pledging over $6 million to its upkeep, and in 2008 he donated $100 million over 10 years to the New York State Theater in the Lincoln Center for the Performing Arts - home of the New York City Ballet.

In 1992, Koch was diagnosed with prostate cancer. He underwent radiotherapy, surgery, and hormone therapy, but cancer repeatedly returned. His largest philanthropic donations went towards cancer research, and between 1998 and 2012 he contributed at least $395 million to the cause.

Koch had a real estate empire worth at least $143 million, with homes in New York City, the Hamptons, Aspen, and Florida. In 1994, following her death, he purchased Jacqueline Kennedy Onassis' 15-room apartment at 1040 Fifth Avenue for $95. million, selling it to billionaire Glenn Dubin in 2006. At the time of his death, he lived primarily in an $18 million 18-room duplex at 740 Park Avenue, Manhattan. It's reported that residents must have a liquid net worth of at least $100 million to live at the address.

He also owned a $40.25 million Manhattan townhouse, which he bought in 2018; an $18.8 million waterfront home in the Hamptons, and a $10.5 million villa in Pam Beach.

Koch was married to Julia Flescher since 1996 and the couple had three children together: David Jr, Mary Julia, and John Mark. They met on a blind date set up by friends in 1991 and she is the president of the David H. Koch Foundation. She is now estimated to be the third richest woman in the world, with a net worth of $43 billion.

David Koch died at his Southampton, New York home on August 23rd, 2019 at the age of 79 from prostate cancer.

Sources: Forbes, Wikipedia, Business Insider

This article was updated on April 13, 2021 by Poppy O'Neill

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