Rex Sinquefield is an American businessman and philanthropist, best known for his contributions to the fields of finance and chess. He co-founded the investment firm Dimensional Fund Advisors and has played a significant role in promoting chess in the United States, particularly in his home state of Missouri. Sinquefield is also known for his support of various educational initiatives and cultural projects. He has funded the construction of the Saint Louis Chess Club, which has become a prominent venue for chess tournaments and events, helping to elevate the profile of the game in the country.