The wealth that Simons has accumulated finances his many philanthropic pursuits. Simons is a benefactor of the mathematical sciences, supporting research projects, chairs, and conferences in the United States and overseas.
James Harris Simons and his second wife, Marilyn Hawrys Simons, founded the Paul Simons Foundation, a charitable organization which supports projects related to education, health and scientific research. Marilyn serves as the foundation’s President, while Jim functions as its Secretary and Treasurer. In memory of his son Paul he established the Avalon Park, a 130-acre (0.53 km2) nature preserve in Stony Brook, New York. In 1996, 34-year-old Paul was killed in a car accident while riding his bicycle near the Simons’ home. Simons’ son, Nick, drowned at age 23 while on a visit to Bali in Indonesia in 2003. Nick had worked in Nepal and the Simonses have donated large contributions to help Nepalese healthcare through the Nick Simons Institute.
On February 27, 2008, then Gov. Eliot Spitzer announced a $60 million donation by the Simons Foundation to establish the Simons Center for Geometry and Physics at Stony Brook, the largest gift to any public university in the history of New York State.
The family’s charitable foundation has committed $38 million to find the causes related to autism. It plans to spend another $100 million in what is becoming the largest private investment in autism research. At the same time, Simons personally exerts extraordinary control over where and how his money is spent. When MIT asked him to fund brain research, he stipulated that the project focus on autism and include scientists of his choosing.
Simons earned about $2.5 billion in 2008, and had an estimated net worth of $8.5 billion. Forbes ranked him as the 80th-richest person in the world and the 29th-richest person in America. In 2006, the Financial Times named him “the world’s smartest billionaire”