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 $10 billion. Sounds hunkydory, right? Well, there’s just one problem: John and David hate each other. Their relationship has deteriorated so badly that Two Sigma has disclosed to 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.
Actually, there are two problems.
John Overdeck is in the middle of a bitter, multi-year divorce with no prenuptial agreement. His wife, Laura Overdeck, claims that billions of dollars in marital assets, including a significant portion of his stake in Two Sigma, were deliberately structured to be “divorce-proof” with the assistance of trusted lawyers and, she alleges, employees at the hedge fund itself. Those claims are fiercely disputed. But if they are allowed to proceed in court, they could drag one of Wall Street’s most secretive firms into subpoenas, depositions, and forced disclosures.
In other words, this is no longer just a story about two billionaires who hate each other.
It is a story about what happens when personal warfare, corporate deadlock, and an $60 billion financial institution collide.
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.
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.
And that ownership structure is the reason this story exists at all.
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 $60 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 “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
Unfortunately, having a net worth of $10 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 $5 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.
Here’s where the math gets especially cruel. David Siegel does not want control. He has reportedly wanted to retire for years. At the same time, he also does not want John Overdeck to run the firm unchallenged. The result is a bizarre stalemate where neither man can move forward without empowering the other in ways they both reject.
In 2024, both founders stepped back from day-to-day management in an attempt to stabilize the firm. The truce did not last. In 2025, Overdeck returned to the company’s management committee, arguing that the post-step-down governance structure had produced paralysis rather than resolution. Siegel did not follow him back.
What might have once been a private marital dispute had now become an existential corporate problem.
Hiding Billions?
The conflict escalated dramatically when Laura Overdeck 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 her filing, she alleged that her husband worked with lawyers at the firm and, she claims, with employees at Two Sigma to “divorce-proof” billions of dollars in assets.
According to Laura, the strategy involved transferring substantial assets, including a significant portion of Overdeck’s ownership in Two Sigma, into irrevocable trusts based in Wyoming. She alleges that these trusts were structured to exclude her in the event of divorce, despite the assets being marital property. Her filings note that John Overdeck has no meaningful personal or business ties to Wyoming.
Laura further claims that the scheme began years before she filed for divorce and that emails produced in discovery show coordination between a Two Sigma employee involved in the family office and Overdeck’s legal counsel. One of the allegations centers on efforts to preserve Overdeck’s sole control over the family foundation.
The claims have not been proven. John Overdeck’s attorneys have called them “baseless, if not frivolous and actionable,” and he has denied that any marital assets were improperly transferred. Still, if the court allows Laura to expand her lawsuit, Two Sigma could be subjected to subpoenas and depositions that expose internal communications, governance practices, and family office operations.
All of this is unfolding against an already turbulent backdrop. In late 2023, Two Sigma disclosed that a former employee had secretly altered key trading models, leading to hundreds of millions of dollars in unreported gains and losses. The episode triggered an SEC investigation and ultimately resulted in a $90 million civil penalty in 2025.
For a firm built on precision, probability, and control, Two Sigma now finds itself at the mercy of the least predictable variables of all: human conflict, litigation, and divorce.
