People searching “Stuart Zimmer net worth” are usually trying to size up a hedge fund manager whose name shows up on SEC insider filings tied to two different companies. This article covers what’s documented about his career and holdings, and what nobody has confirmed. If you’ve seen wildly different dollar figures floating around, you’re not imagining things — we’ll explain why.
Background
Stuart J. Zimmer, sometimes listed in filings as Stuart Jason Zimmer, is the founder and Managing Member of Zimmer Partners LP, an investment firm that focuses on utilities, energy, and infrastructure-related companies. He’s also Chairman and CEO of Zimmer Energy Transition Acquisition Corp, a publicly traded special purpose acquisition company, and Chairman of Ategrity Specialty Insurance Company Holdings, a specialty insurance business.
He isn’t a household name the way a movie star or senator would be. People land on his name mostly through stock-tracking sites and SEC insider-trading databases, because his personal wealth is tied almost entirely to shares he holds in companies where he sits on the board or serves as an executive. That’s also exactly why net worth numbers about him bounce around so much — they move with the stock price, not with any confirmed personal statement about his finances.
Why this matters: Several finance data sites publish a “net worth” for Stuart Zimmer that is really just an estimate of his stock holdings on a given date. That is a very different thing from a confirmed personal net worth, which he has never publicly disclosed.
Latest Update
As of September 12, 2026, here is what’s currently known. There is no confirmed news of a scandal, legal trouble, health issue, or major life event involving Stuart Zimmer. His name is trending mainly because stock-tracking and insider-trading sites keep republishing updated estimates of his holdings as share prices move, which keeps pulling up new “net worth” headlines without any actual new development behind them.
Those tracking sites have shown his estimated holdings moving between roughly $737 million in April 2026 and over $1 billion by mid-2026, largely because of price swings in Ategrity Specialty Insurance Company Holdings (ticker ASIC) stock, which makes up the bulk of his disclosed position. No credible outlet has confirmed a specific, fixed net worth figure for him as a person — everything public is an estimate built from his known share count multiplied by a moving stock price.
Unconfirmed: Some low-quality “net worth” sites online describe a completely different biography for a “Stuart Zimmer” — a Silicon Valley tech founder who ran a data analytics company. That is not the same person as the hedge fund executive this article covers, and that alternate biography could not be verified against any credible source.
Full Profile
Family and Early Life
Detailed information about Stuart Zimmer’s childhood, siblings, or family background has not been published by any verifiable source. This is common for finance executives who keep a low public profile outside of required securities filings.
Career Path
Zimmer’s career traces back to 1991, when he joined Steinhardt Partners, a hedge fund led by Michael Steinhardt, widely regarded as one of the industry’s early influential figures. At Steinhardt, Zimmer worked as a research analyst covering energy names, including electric and gas utilities, and also gained experience trading equities, fixed income, currencies, and derivatives.
In 1993, he left to help start a utility-focused hedge fund backed by Commodities Corporation, where he eventually became the fund’s sole portfolio manager. In 1997, he co-founded Zimmer Lucas Capital (also referenced as Zimmer Lucas Partners LLC), which ran the same utility strategy until December 2012. From there, he became Managing Member of Zimmer Partners LP, the firm he still leads today. Separately, he took on the Chairman role at Ategrity Specialty Insurance Company Holdings in 2018, and became Chairman and CEO of Zimmer Energy Transition Acquisition Corp in 2021.
Age
A 2023 corporate filing listed Zimmer’s age as 52, and separate stock-tracking profiles have listed him as 57 to 58 years old in 2026. Together these point to a birth year somewhere around 1969 to 1970, but no source has published a confirmed birthdate, so his exact age should be treated as approximate.
Religion
Zimmer’s religious beliefs, if any, have not been publicly disclosed anywhere. This should be treated as unconfirmed rather than assumed one way or another.
Spouse/Partner
No verified source confirms whether Stuart Zimmer is married or has a partner. This detail is not covered in any of the SEC filings, corporate bios, or finance profiles that discuss his career.
Net Worth
This is the figure most people are searching for, and it’s also the messiest part of his public profile. Insider-trading trackers that pull from SEC Form 4 filings have estimated his holdings at figures ranging from about $737 million to more than $1.2 billion across different points in 2026, depending on the trading day used to price his shares in Ategrity Specialty Insurance Company Holdings and Zimmer Energy Transition Acquisition Corp.
These numbers are built entirely from public share ownership disclosures, not from a personal financial statement, tax filing, or independently audited wealth ranking like Forbes uses for its billionaire list. He does not currently appear on Forbes’ billionaires index. Because of that, any single number you see quoted as “his net worth” should be read as a snapshot estimate tied to a stock price on a specific day, not a fixed or confirmed fact.
Reader caution: A separate website using the same name describes a $10 million to $123 million net worth for a tech entrepreneur. That page cannot be verified as describing the same Stuart Zimmer covered in this article and should not be used as a source for his finances.
Parents
No confirmed information about Stuart Zimmer’s parents has been published in any credible outlet, biography, or filing reviewed for this article.
Height
Height is not something typically disclosed for finance executives, and Zimmer’s is not listed in any public record found for this article. Unconfirmed.
Education
Zimmer graduated from Harvard College with honors in mathematics and was inducted into Phi Beta Kappa, the academic honor society. This detail is repeated consistently across multiple independent finance-industry bios, which gives it stronger confirmation than most other personal facts about him.
Hometown/State of Origin
No source reviewed for this article confirms where Stuart Zimmer grew up or which state he originally calls home. Treat this as unconfirmed until an official biography states otherwise.
Official Social Media / Website
Zimmer does not appear to maintain a public personal social media account. The closest verifiable official source tied to his work is his firm’s regulatory presence on the SEC’s EDGAR filing system: SEC EDGAR — Zimmer Partners LP filings.
Key date to remember: September 12, 2026 — the date this profile’s “Latest Update” section was last verified.
Quick Facts Table
| Category | Detail |
|---|---|
| Full Name | Stuart J. (Jason) Zimmer |
| Known For | Founder, Zimmer Partners LP; Chairman & CEO, Zimmer Energy Transition Acquisition Corp; Chairman, Ategrity Specialty Insurance Co Holdings |
| Approximate Age (2026) | 57 to 58 (unconfirmed exact birthdate) |
| Education | Harvard College, Phi Beta Kappa, Honors in Mathematics |
| Career Start | 1991, Steinhardt Partners (research analyst, energy sector) |
| Firm Founded | Zimmer Partners LP, December 2012 (Managing Member since inception) |
| Estimated Holdings (2026, varies by date) | Roughly $737 million to over $1.2 billion, based on SEC insider filings |
| Confirmed Personal Net Worth | Not publicly disclosed — unconfirmed |
| Spouse/Partner | Unconfirmed |
| Hometown | Unconfirmed |
Reader Questions (FAQ)
How much is Stuart Zimmer actually worth?
There is no single confirmed figure. SEC-based insider-ownership estimates in 2026 have ranged from about $737 million to more than $1.2 billion, moving with the stock price of Ategrity Specialty Insurance Company Holdings and Zimmer Energy Transition Acquisition Corp. Zimmer has not personally confirmed a net worth figure, and he does not appear on major independently audited wealth rankings.
What company does Stuart Zimmer run?
He is the Managing Member and CEO of Zimmer Partners LP, an investment firm focused on utilities, energy, and infrastructure. He also serves as Chairman and CEO of Zimmer Energy Transition Acquisition Corp and Chairman of Ategrity Specialty Insurance Company Holdings.
Is Stuart Zimmer a billionaire?
Some insider-trading estimates have placed his stock-based holdings above $1 billion at certain points in 2026, but this is an estimate tied to share ownership, not a confirmed personal fortune verified by an independent wealth-tracking organization like Forbes. He does not currently appear on Forbes’ billionaires list, so calling him a confirmed billionaire would be premature.
Where did Stuart Zimmer go to college?
He attended Harvard College, graduating with honors in mathematics and earning membership in Phi Beta Kappa. This is one of the most consistently confirmed facts about his background across multiple independent finance profiles.
Is Stuart Zimmer married?
This has not been publicly confirmed. No credible source reviewed for this article discusses his marital status, so it should be treated as unconfirmed rather than assumed.
Why do net worth estimates for Stuart Zimmer keep changing?
Because the estimates are calculated from his disclosed share counts multiplied by the current stock price of the companies he’s tied to, mainly Ategrity Specialty Insurance Company Holdings. As that stock price moves up or down, the estimate moves with it, which is why you’ll see different numbers depending on which day a site pulled its data.
Is the “Stuart Zimmer, tech entrepreneur” net worth story about the same person?
No, it does not appear to be. That story describes a Silicon Valley founder of a data analytics company, which does not match any verified detail about the hedge fund manager Stuart J. Zimmer covered in SEC filings and finance profiles. Treat that version as unconfirmed and likely about a different individual, if it refers to a real person at all.
Wrap-Up
Stuart Zimmer’s public profile is a good example of how confusing online net worth reporting can get once a name is shared by multiple estimate-generating websites. What’s actually confirmed is fairly narrow: a decades-long career in utility and energy-focused investing, leadership roles at three specific companies, and a Harvard education. What’s presented as his “net worth” is really a moving estimate built from public stock filings, not a number he has ever confirmed himself.
If you searched his name because you saw a big dollar figure somewhere, the honest answer is that it depends entirely on which day’s stock price was used to calculate it. There’s no evidence of a scandal, life event, or new business move driving current search interest — just automated net worth trackers updating their pages.
As with most executives who aren’t household names, treat any personal detail beyond his professional record — family, relationships, religion, physical details — as unconfirmed unless a credible outlet reports it directly. This article will be updated if any of that changes.
Research completed and cross-checked on September 12, 2026, using SEC filing trackers, insider-ownership databases, and independent finance profiles. Figures involving stock-based net worth estimates will change as share prices move.
Thomas Andrew is the founder of Odubio.com, a digital platform sharing inspiring biographies, news, and stories about global icons and achievers.