William Singer is the youngest son of Paul Singer, the billionaire founder of Elliott Management Corporation, and his ex-wife Mary Singer. Unlike his older brother Andrew, who has been more publicly active in philanthropy and advocacy, particularly in LGBTQ+ causes, William maintains a lower profile. He is known to be involved in the family's philanthropic endeavors through organizations supported by the Singer family foundation, though specific roles or initiatives attributed directly to him are not widely documented in public sources.