Billionaire investor Bill Ackman has four children, all daughters, from his two marriages. Three were born during his marriage to landscape architect Karen Ann Herskovitz, while his youngest child arrived after he married designer and former MIT professor Neri Oxman.
Ackman is one of Wall Street’s most outspoken investors, but his daughters have generally grown up far removed from the attention surrounding his business career.
That separation between public and private life changed significantly in 2026 when Ackman revealed that his 26-year-old daughter, Lucy Ackman, had experienced a devastating brain hemorrhage.
Her remarkable progress during rehabilitation subsequently became the inspiration for one of the biggest philanthropic projects Ackman and Oxman have undertaken.
Four Daughters
Bill Ackman is the father of four daughters.
He shares three children with his former wife, Karen Herskovitz, whom he married in 1994. The couple separated in 2016 after more than two decades together and later divorced.
Ackman subsequently married Neri Oxman in January 2019 at Central Synagogue in Manhattan.
The couple welcomed their first daughter together in the spring of 2019.
While Ackman’s financial activities regularly generate international headlines, he has generally avoided making his children central to his public identity.
Karen Herskovitz
Ackman’s first wife, Karen Ann Herskovitz, is a landscape architect.
Their marriage began years before Ackman became the billionaire investor recognized around the world today.
The couple had three daughters together.
Their family life developed alongside Ackman’s increasingly prominent financial career, which included establishing Gotham Partners and later founding Pershing Square Capital Management.
Herskovitz was also involved in the family’s philanthropic activities. Ackman and Herskovitz established the Pershing Square Foundation in 2006.
They ultimately separated in 2016.
Neri Oxman
Ackman’s second wife, Neri Oxman, has an internationally recognized career of her own.
Born in Israel, Oxman became known for combining architecture, biology, engineering and computational design.
She was a professor at the Massachusetts Institute of Technology and founded the Mediated Matter research group at MIT Media Lab. Her multidisciplinary approach has made her an influential figure across architecture, technology and material design.
Ackman and Oxman became engaged in 2018 and married the following year.
Their daughter was born in spring 2019, giving Ackman his fourth child.
The couple have kept details about their young daughter’s everyday life largely private.
Lucy Ackman
One of Ackman’s adult daughters, Lucy Ackman, became the focus of public attention in 2026 because of an extraordinary medical emergency.
Lucy was 26 when she experienced a severe brain hemorrhage in February 2026.
Ackman later explained publicly that his daughter was found unconscious in her apartment many hours after the medical emergency began.
Her condition was extremely serious.
According to Ackman’s account of the experience, pressure caused by the hemorrhage produced extensive neurological injuries and severely affected important functions, including her vision and ability to communicate.
What followed was an intensive period involving hospital treatment, specialist care and rehabilitation.
Lucy’s Recovery
Lucy’s progress profoundly affected her father.
Ackman has spoken about doctors pursuing advanced approaches during her treatment and the family’s determination to explore options that could improve her outcome.
Although she faced enormous challenges, her condition gradually improved.
Her experience exposed Ackman to the complexities of neurological medicine, particularly the enormous gap between emergency intervention and the long process of rehabilitation after serious brain injuries.
For an investor accustomed to examining industries and identifying structural problems, the experience prompted a new question: could substantially greater resources accelerate innovation in neuroscience and recovery?
That question became the foundation of an ambitious new project.
Brain Institute
In 2026, Ackman and Oxman announced plans for the Ackman Oxman Institute, known as AOI.
The nonprofit Manhattan institution is intended to bring together research, clinical expertise, technology and rehabilitation under a broad brain-science mission.
Its planned areas of work include neuroscience, brain recovery, rehabilitation, brain-computer interfaces, human performance and longevity.
Ackman has said he wants the organization to help bridge gaps between academic research, medical institutions and technologies capable of reaching patients.
The initiative is expected to work with Mount Sinai as well as other hospitals, medical schools and researchers.
Lucy’s experience was a central catalyst for the project.
$400 Million Gift
Ackman and Oxman provided extraordinary financial backing for their plans in August 2026.
A regulatory filing shows that 10 million shares of Pershing Square Inc. were transferred on August 17 as a gift.
At market prices around the announcement, those shares were valued at approximately $400 million.
Rather than simply providing money intended for immediate spending, Ackman has described the shares as a financial foundation capable of generating long-term value and dividend income for the organization.
He has also indicated that another contribution of similar or potentially greater value is planned, although that additional commitment will not take the form of Pershing Square stock.
If fully realized, the scale of the project could make AOI a significant privately backed institution in neurological research.
Manhattan Campus
The Ackman Oxman Institute is being developed on Manhattan’s Upper West Side.
The Pershing Square Foundation acquired an approximately 400,000-square-foot building for the project.
Ackman has also said the foundation is under contract to purchase another roughly 130,000-square-foot property nearby, along with an adjoining vacant lot and associated development rights.
The goal extends beyond constructing another conventional research laboratory.
Ackman has described ambitions for a multidisciplinary environment bringing scientists, physicians, engineers and other specialists together around problems involving the human brain.
Family Privacy
The attention surrounding Lucy is unusual for the Ackman family.
Despite Bill Ackman’s exceptionally public personality, most of his daughters have maintained comparatively private lives.
His youngest daughter with Oxman is still a child, making that privacy particularly important.
Even Lucy’s increased public visibility has largely resulted from Ackman’s decision to explain the personal motivation behind his new neuroscience initiative rather than an attempt to turn his family into public personalities.
The distinction has allowed Ackman’s children to remain largely separate from his frequent appearances in financial and political discussions.
Family And Philanthropy
For readers searching for Bill Ackman children, the basic answer is straightforward: the billionaire investor has four daughters, three from his marriage to Karen Herskovitz and one with Neri Oxman.
In 2026, however, his family story became unexpectedly intertwined with his philanthropy.
Lucy’s February brain hemorrhage exposed Ackman and Oxman to the immense challenges surrounding neurological treatment and rehabilitation. Her subsequent progress helped motivate them to commit hundreds of millions of dollars toward building an institution designed to advance those fields.
The result is a project considerably larger than one family’s medical experience.
Through the Ackman Oxman Institute, Ackman and Oxman are attempting to turn what they learned during their daughter’s medical crisis into research and treatments that could eventually benefit many other patients and families facing serious neurological injuries.
