Our Team
William C. Thompson
Co-Founder & Senior Advisor
Bill is a Co-Founder and Senior Advisor of American Triple I. Bill was previously the 42nd Comptroller of New York City, serving eight years from January 2002 to December 2009. Bill’s experience in managing the finances of the nation’s largest city has afforded him insight into the infrastructure needs of local and state governments and gives him keen sensitivity to the expectations and requirements of large institutional investors. As Comptroller, Bill served as fiduciary to the five New York City Pension Funds, where he oversaw a combined portfolio for the five plans. While serving as the Comptroller, the New York City plan invested billions of dollars across various strategies including real assets and infrastructure. During his tenure, Bill also worked with leaders of the financial services industry to reform the operations of the New York Stock Exchange and spearheaded the City’s innovative Banking Development District program. Prior to his work as Comptroller, he had served as Brooklyn Deputy Borough President and as a Member and five-term President of the New York City Board of Education. Bill also served as a Senior Vice President in Public Finance in the mid-1990s.
In addition to his role as Senior Advisor for ATI, Bill is Chief Administrative Officer and an equity owner of Siebert Williams Shank & Co.
Bill has a Bachelor of Arts degree from Tufts University.
Bill is a Co-Founder and Senior Advisor of American Triple I. Bill was previously the 42nd Comptroller of New York City, serving eight years from January 2002 to December 2009. Bill’s experience in managing the finances of the nation’s largest city has afforded him insight into the infrastructure needs of local and state governments and gives him keen sensitivity to the expectations and requirements of large institutional investors. As Comptroller, Bill served as fiduciary to the five New York City Pension Funds, where he oversaw a combined portfolio for the five plans. While serving as the Comptroller, the New York City plan invested billions of dollars across various strategies including real assets and infrastructure. During his tenure, Bill also worked with leaders of the financial services industry to reform the operations of the New York Stock Exchange and spearheaded the City’s innovative Banking Development District program. Prior to his work as Comptroller, he had served as Brooklyn Deputy Borough President and as a Member and five-term President of the New York City Board of Education. Bill also served as a Senior Vice President in Public Finance in the mid-1990s.
In addition to his role as Senior Advisor for ATI, Bill is Chief Administrative Officer and an equity owner of Siebert Williams Shank & Co.
Bill has a Bachelor of Arts degree from Tufts University.