They Co-Own A $60 Billion Hedge Fund. They're Both Worth $8 Billion. They Hate Each Other… And One Is Getting Divorced With No Prenup

John Overdeck and David Siegel have run a hedge fund called Two Sigma for over two decades. Two Sigma manages $60 BILLION in assets. According to Wikipedia's list of the world's largest hedge funds, Two Sigma ranks as the eighth-largest hedge fund in the world. HOWEVER. Wikipedia lists Two Sigma's assets under management at $40 billion. The actual number is $60 billion. When you use $60 billion, Two Sigma is the fifth-largest hedge fund in America, just ahead of a firm called D.E. Shaw, which will feature again in this story in a moment.

As you might guess, John and David are both multi-billionaires. They are the only owners of Two Sigma. They have equal voting power over all company decisions, and they both have a net worth of $8 billion. Sounds hunkydory, right? Well, there's just one problem: John and David hate each other. They reportedly can't even communicate with each other over basic firm operational decisions.

Actually, there are two problems.

John Overdeck is going through a billion-dollar divorce, and his wife, Laura Overdeck, claims that employees at Two Sigma helped him shield billions in assets…

David Siegel, Michael Bloomberg, and John Overdeck (Photo by Craig Barritt/Getty Images for Bloomberg)

How do you split a $60 billion hedge fund?

John Overdeck is a math genius. Math is in his blood. His father was a senior mathematician for the NSA. His mother was a director at Computer Sciences Corporation, a pioneer in the IT field. In 1986, when he was 17, John won a silver medal at the International Math Olympiad. He earned a degree in math and statistics at Stanford before enrolling in Stanford's graduate school to earn a Ph.D in… get this… math.

John never got that Ph.D from Stanford. In the 1990s, he was recruited away from school to join a recently launched math-focused hedge fund called D.E. Shaw. At D.E. Shaw, John quickly rose to the position of managing director of risk management.

More importantly, while he was at D.E. Shaw, John caught the attention of the firm's youngest Senior Vice President, a 30-year-old fellow math nerd named Jeffrey Preston Bezos.

Jeff had recently married his research assistant, the future MacKenzie Scott. In 1994, the newlywed Bezos quit their respective jobs at D.E. Shaw, packed up their apartment, and drove across the country in a Volvo headed towards Seattle. MacKenzie drove while Jeff typed up a business plan for a new e-commerce business he was calling "Cadabra" (as in "abracadabra). After Jeff's lawyer misheard "Cadabra" as "cadaver," Jeff decided to pick a new name. He settled on Amazon.

One of the first people Jeff recruited to join him in Seattle was… John Overdeck. John's title said Vice President, but he was really Jeff Bezos's technical assistant.

John worked at Amazon for two crucial years, from roughly 1995 to 1997. I couldn't figure out exactly when he joined or when he left, but considering Amazon went public in May of 1997, it's probably safe to assume that John worked through the IPO, made a small fortune, and decided to take a few years off to enjoy his riches.

FYI, on the IPO date, Jeff Bezos ended the day with a net worth of $120 million. A year later, he was a billionaire. By late 1999, Bezos was worth $10 billion. After the dotcom bubble exploded in 2001, Bezos' net worth crashed all the way back down to $2 billion.

That same year, John and another D.E. Shaw alum named David Siegel decided to launch a hedge fund. They called it Two Sigma. There was actually a third founder named Mark Picard, but he retired in 2006.

Two Sigma

Right out of the gate, Two Sigma raised over $100 million from investors, including Jeff Bezos.

In its first decade of operation, Two Sigma returned an average of 30% per year to its investors. This was significantly higher than the average return generated by the average hedge fund in the same time period.

Two Sigma's success was due to its use of cutting-edge technology and its focus on quantitative analysis. The firm employed hundreds of mathematicians, physicists, and computer scientists to develop trading algorithms that could exploit market inefficiencies.

Based in Manhattan's SoHo neighborhood, Two Sigma cultivated a culture closer to Silicon Valley than Wall Street, complete with chess tournaments and a staff of more than 2,000 engineers, data scientists, and mathematicians. For years, the firm prided itself on secrecy. The two founders, especially, were obsessed with avoiding publicity.

As we stated previously, Two Sigma is one of the largest hedge funds in the world today with $60 billion under management. John and David's former firm, D.E. Shaw, manages around $50 billion.

And, for a variety of reasons, despite all their success, John and David hate each other.

Over the years, John and David have clashed plenty of times over everything from succession planning, promotions, and investment decisions. That's not abnormal. What is abnormal is when the animosity between the owners gets so bad that the fund is forced to make an SEC disclosure that basically says "our founders hate each other, they're unable to make basic decisions together, and that might turn into a risk for investors."

John and David haven't appeared at an event together in years. The photo at the top of this article, where they are separated by Michael Bloomberg, is from 2017. It's the most recent photo of them together I could find in Getty. Insiders claim they frequently "snipe" at each other during meetings in front of subordinates.

As the company itself admits, the friction is making it difficult "to retain or attract employees (including very senior employees) and could continue to impact the ability of employees to fully implement key research, engineering, or corporate business initiatives."

John and David each have equal voting rights (one vote per person), and they are using their votes to turn every single decision, no matter how trivial, into a stubborn stalemate. There's no mechanism for breaking the stalemate. And that's a huge problem considering what is going on in John's personal life.

John and Laura Overdeck via Getty

John & Luara

In 2002, John married Laura Anne Bilodeau. They did not sign a prenup. John and Laura would go on to have three children together. Laura studied astrophysics at Princeton.

In 2011, they established the Overdeck Family Foundation, which primarily focuses on STEM education charities and research. Guess what the "M" in "STEM" stands for… MATH. To date, their foundation has given away more than $450 million.

In 2012, Laura founded a non-profit called Bedtime Math, a free website and app with the goal of making "math a fun part of kids' everyday lives, as beloved as the bedtime story."

Unfortunately, that love of math is not helping David, John, and Laura figure out how to divide Two Sigma by two.

Their equity stakes in Two Sigma have given both John and David a net worth of $8 billion. John is one of the richest people in New Jersey.

After 20 years of marriage, WITH NO PRENUP, Laura filed for divorce in 2022. That divorce has been dragging on for over three years.

$8 Billion Divorce

Unfortunately, having a net worth of $8 billion that is largely based on the equity value of a private company doesn't mean you have billions in liquid cash lying around to pay out a divorce settlement. And that's where a new conflict has arisen.

Common sense would say that Laura is entitled to a payout of around $4 billion. But! John can't give her that payout without selling part of his stake in Two Sigma. He doesn't want to do this because selling some of his equity would give David majority ownership, and therefore full control. And in another twist, David doesn't even want to be in control. He wants to retire, but he also DOESN'T want John to be in charge.

Both men stepped back from day-to-day management in 2024, though Overdeck returned to the company's management committee earlier this year.

It all adds up to an extremely difficult problem that won't be easily solved, no matter how much you love math.

Hiding Billions?

This week, Laura asked a New Jersey court for permission to amend her lawsuit against Seward & Kissel, the law firm that handled the couple's estate planning. In the filing, she alleged that Two Sigma employees helped her husband "divorce-proof" billions in assets, including a significant portion of his ownership in the hedge fund, by transferring them into irrevocable Wyoming trusts he controls. Laura's filing also points out that John has no properties or other ties to the state of Wyoming.

According to Laura, the scheme began years before she filed for divorce and involved lawyers at Seward & Kissel working closely with Two Sigma staff who managed the couple's family office. Emails produced in discovery allegedly show coordination between a Two Sigma employee and Overdeck's attorney about maintaining his sole control over the family foundation.

The allegations have not been proven, and John Overdeck's lawyers have called them "baseless, if not frivolous and actionable." But if the court grants Laura permission to amend her lawsuit, Two Sigma could soon face subpoenas and depositions — dragging the $60 billion firm into a bitter domestic dispute between its co-founder and his wife.

These new claims come at a turbulent time for Two Sigma. In late 2023, Two Sigma disclosed that one of its employees had secretly altered key trading models, causing hundreds of millions in unreported gains and losses across several portfolios. The revelation led to an SEC investigation and ultimately a $90 million penalty in 2025.