Meet Julia Flesher Koch, the Iowa-born socialite who's now one of the world's richest women after inheriting a chunk of her late husband David Koch's $53 billion fortune

Julia Flesher Koch is the wife of late billionaire industrialist David Koch, who died in August 2019 as the seventh-richest person in America.

When he died, Koch controlled a fortune estimated at $53.5 billion, making him the seventh-richest American in a tie with his brother, Charles Koch, according to the Forbes 400 ranking.

Flesher Koch and Koch were married for 23 years.

After her husband's death, Flesher Koch became one of the world's richest women.

Bloomberg pegs Flesher Koch's net worth at $61.6 billion, which would make her the richest woman in the world.

Forbes, on the other hand, estimates her wealth to be significantly less, at $43 billion, which would make her the third-richest woman in the world after Francoise Bettencourt Meyers and Alice Walton.

The discrepancy could be explained by different estimates of how much Koch left to his wife versus his three children, as well as fluctuations of the valuation of Koch Industries. A spokesperson for Koch Industries told Business Insider that Koch's shares of the company remained with the family after his death, but declined to offer any more details on her net worth.

Born and raised in Iowa, Flesher Koch moved to New York in 1984 and became part of the high society scene.

In the early 1990s, she was photographed at high-profile events such as the opening of the Metropolitan Museum of Art's Costume Institute Exhibition.

She worked as an assistant to fashion designer Adolfo.

Flesher Koch met David Koch on a blind date set up by friends in January 1991.

But they didn't immediately hit it off, 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.

After their marriage, Flesher Koch became an esteemed fixture on the New York social scene, according to the Times.

"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."

In 1998, Vogue editor picked Flesher Koch to serve as co-chairwoman for that year's Met Gala.

The New York couple had three children together: David Jr., Mary Julia, and John Mark.

The oldest of their children is college-aged.

Koch's nephew, Chase Koch, has reportedly been taking over his uncle's duties as a key figure at Koch Industries.

Flesher Koch and her husband together owned at least $143 million worth of real estate in New York City, the Hamptons, Aspen, and Florida at the time of his death.

For years, they lived in a 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 Times.

In 2004, the couple's primary residence became a massive 18-room duplex in a ritzy Manhattan building that John D. Rockefeller, private equity billionaires, and other business magnates have called home.

Koch paid $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 at the Art Deco co-op, which opened in the 1930s, applicants reportedly must be able to show a liquid net worth of at least $100 million, as Business Insider reported in 2017.

The couple also owned a $40.25 million Manhattan townhouse.

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, includes a 1,500-square-foot master suite, a gym, and a rooftop terrace.

Then there's the oceanfront mansion on "Billionaire Lane" in the Hamptons, the ritzy vacation destination for New York City's wealthy elite.

The seven-bedroom Southampton home, where Koch and Flesher Koch were married, has a tennis court, an outdoor swimming pool, and a current estimated value of more than $30 million, according to Zillow.

The Hamptons street where the house sits, Meadow Lane, was nicknamed "Billionaire Lane" for its ultra-wealthy residents, who have reportedly included investor David Och, real estate mogul Aby Rosen, fashion designer Calvin Klein, and hotelier Ian Schrager.

The couple also purchased homes in Aspen, an upscale Colorado ski town, and Palm Beach, Florida.

Property records for the county show that Koch bought his first Aspen house for $1.9 million in 1989. Two years later, in 1991, he paid $1.75 million for another home on the same street.

Today, the first home has an estimated value of almost $18 million, and the second is valued at $8.6 million, according to Zillow.

The Kochs also had a 30,000-square-foot mansion in Palm Beach, Florida, called the Villa el Sarmiento, that they reportedly bought for $10.5 million in 1998 and spent another $12 million renovating.

Today, the mansion is worth an estimated $37 million.

A representative for Koch Industries declined to comment on the couple's real-estate holdings.

Flesher Koch is the president of the David H. Koch Foundation, which has given more than $200 million to various causes including science and medical research, education, and the arts, according to its website.

With his brother, Charles, David Koch donated at least $100 million to help the rise of the Tea Party movement and to bolster the Republican Party since the 1970s, according to The New York Times.

Before she was president of her late husband's foundation, Flesher Koch, now 57, previously served on the Board of Directors for the School of American Ballet. She also chaired events for Memorial Sloan Kettering Cancer Center, Food Allergy Research & Education, and American Ballet Theater.

A representative for Koch Industries declined to comment on Flesher Koch's philanthropic endeavors or other activities.