They Co-Own A $80 Billion Hedge Fund. They're Both Worth $10 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.

According to Wikipedia's list of the world's largest hedge funds, Two Sigma ranks as the eighth-largest hedge fund in the world with $51 billion in assets under management (AUM). HOWEVER. Wikipedia is extremely out of date. Two Sigma actually manages $80 billion worth of assets. How do we know that specific number? John recently had to reveal it in court testimony. More on this in a moment.

I just did some research, and here is a current list of the 10 largest hedge funds in the world:

1. AQR Capital Management — $1115 billion
2. Bridgewater Associates — $102 billion
3. BlackRock hedge fund strategies — $98 billion
4. Millennium Management — $92  billion
5. Man Group — $90 billion
6. Two Sigma — $80 billion
7. Elliott Investment Management — $80 billion
8. TCI Fund Management — $77 billion
9. D.E. Shaw — $75 billion
10. Citadel — $71 billion

So there you go. Two Sigma is the sixth-largest hedge fund in the world. And as you might guess, being co-founders of the world's sixth-largest hedge fund has turned John and David into multi-billionaires. They both have a net worth of $10 billion. They are the only owners of Two Sigma. They have equal voting power over all company decisions. Sounds hunkydory, right? Well, there are just two tiny problems:

Problem #1: John and David hate each other.

Their relationship is so bad that Two Sigma actually had to disclose to its investors that the feud between its co-founders poses a "material risk" to the firm. Insiders say the two men rarely speak directly, avoid appearing together, and often require intermediaries to handle even routine decisions.

Problem #2) John Overdeck is currently in the middle of a bitter, multi-year divorce with no prenuptial agreement.

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

How do you split an $80 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.

In 2001, as the technology bubble deflated, Overdeck returned to finance. He reunited with another D.E. Shaw alumnus, David Siegel, to launch a new hedge fund built entirely around data, probability, and computing power. They named it Two Sigma, a statistical reference that reflected their core belief: markets could be understood and exploited through math.

There was technically a third founder, Mark Picard, but he retired in 2006. From that point forward, Two Sigma belonged to just two people.

Two Sigma

Two Sigma launched in 2001 with more than $100 million in seed capital, including an early investment from Jeff Bezos. From the beginning, the firm was designed to look less like a traditional hedge fund and more like a research lab, built around the idea that markets could be understood and exploited through data, probability, and computing power rather than human intuition.

During its first decade of operation, Two Sigma reportedly generated average annual returns of around 30%, far outpacing the broader hedge fund industry. Its edge came from an obsessive focus on quantitative analysis and technology. The firm hired mathematicians, physicists, engineers, and computer scientists to build trading models capable of identifying subtle patterns and inefficiencies across global markets.

Headquartered in Manhattan's SoHo neighborhood, Two Sigma cultivated a culture that felt closer to Silicon Valley than Wall Street. Chess tournaments, internal coding challenges, and an emphasis on academic-style research became part of its identity. Over time, the firm grew to employ more than 2,000 people across offices around the world. For years, Two Sigma prided itself on secrecy. Both founders, especially, worked hard to avoid publicity and public scrutiny.

Today, Two Sigma manages roughly $80 billion in assets, making it one of the largest hedge funds in the world. John and David's former firm, D.E. Shaw, manages closer to $50 billion. On paper, Two Sigma is an extraordinary success story.

And yet, despite all of that success, John Overdeck and David Siegel cannot stand each other.

Over the years, the two co-founders have clashed over succession planning, promotions, compensation, governance, and strategic direction. Disagreements at that level are not unusual in finance. What is unusual is when the animosity becomes so severe that the firm is forced to warn investors about it.

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

John Overdeck married Laura Anne Bilodeau in 2002. They did not sign a prenuptial agreement. Over the course of their marriage, they had three children together. Laura studied astrophysics at Princeton and later earned an MBA from Wharton.

In 2011, the couple founded the Overdeck Family Foundation, which focuses primarily on STEM education and research. To date, the foundation has donated more than $450 million. The following year, Laura founded Bedtime Math, a nonprofit website and app designed to make 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 $10 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.

$10 Billion Divorce

In August 2026, John and Laura Overdeck's divorce finally went to trial in New Jersey Superior Court. Laura's attorney described it as the biggest contested divorce in New Jersey history.

Here's the central question: Is John's ownership stake in Two Sigma marital property at all?

John's attorneys say no. Their argument is that he co-founded Two Sigma in 2001, nearly two years before he married Laura. According to his legal team, the company had already developed its trading systems, raised money, and was managing hundreds of millions of dollars before the wedding. Therefore, they argue, John acquired his stake before the marriage and Laura is not entitled to a percentage of it.

Laura's lawyers see things very differently. They claim Two Sigma was barely more than a concept before the marriage, did not begin actively trading until afterward, and that John's ownership interest did not actually vest until after the couple wed.

There's also the question of when the enormous value was created.

Two Sigma had less than $100 million in assets under management around the time it was founded.

Today, according to John's own testimony this week, Two Sigma manages $80 billion.

Laura's argument is essentially that even if John planted the seed before their marriage, nearly the entire forest grew while they were married.

$723 Million Vs. Billions

The opening statements also revealed for the first time how much John is actually offering Laura.

According to John's attorney, he has proposed giving Laura $723 million in equitable distribution, tax-free.

Laura says it isn't nearly enough. She is seeking 35% of the value of John's ownership stake in Two Sigma.

And, naturally, they can't even agree on what that stake is worth.

Laura's lawyers value John's Two Sigma stake at approximately $6.2 billion. Thirty-five percent of $6.2 billion is around $2.17 billion.

John's side values the stake at a considerably lower $4.9 billion. Even at that valuation, 35% would be around $1.7 billion.

And that's not everything Laura is seeking.

Her attorneys are also asking for hundreds of millions of dollars in Treasury bonds held in a revocable trust.

Then there's the Overdeck Family Foundation.

According to its 2024 tax filing, the foundation held approximately $920 million in assets. Laura wants to be restored to equal control of the foundation. Alternatively, she wants John ordered to contribute an amount equal to half of the foundation's value to a charity of her choosing.

John's attorney argues that the $723 million offer is more than sufficient to maintain the lifestyle Laura enjoyed during their marriage. He also claims John earned $685 million during the marriage and deposited all of it into the couple's joint account.

Laura's lawyers accuse John of spending years making sure she would receive as little as possible if the marriage ever ended.

Which brings us back to those Wyoming trusts.

Hiding Billions?

Laura has separately accused John of taking steps years before their breakup to "divorce-proof" billions of dollars in assets.

According to court filings, John kept a notebook in his New Jersey home in which he wrote the words "divorce-proof." Laura later found the notebook while searching his home office.

Laura's attorneys point to that note as evidence that John had been planning for the possibility of divorce years before she actually filed.

John disputes that interpretation. He has testified that the note referred to estate planning for younger relatives and the possibility that their own future marriages could someday end in divorce.

Laura is also separately suing Seward & Kissel, the law firm involved in the couple's estate planning. She alleges that the firm worked with John to restructure assets in ways that would exclude her if she filed for divorce, despite her belief that the firm represented both spouses.

According to Laura, billions of dollars in assets, potentially including a significant portion of John's Two Sigma holdings, were transferred into irrevocable Wyoming trusts. She has also alleged that Two Sigma employees involved with the family's investment office assisted with aspects of the planning.

John emphatically denies those allegations. He has testified that "not one dime" of marital property was improperly transferred into the Wyoming trusts and says the structures were established for legitimate estate-planning purposes benefiting his children and future generations.

Those claims remain heavily disputed.

For three people who have spent much of their lives obsessed with mathematics, they have somehow arrived at an equation with no obvious solution.