Former Treasury Official Warns Americans Need To Worry About Not Just About Soaring US Debt, But Also About Who Is Buying It: Report Rounak Jain Mon, December 29, 2025 at 5:16 PM GMT+5:30 3 min read Geng Ngarmboonanant, managing director at JPMorgan Chase & Co., and former deputy chief of staff to former Treasury Secretary Janet Yellen, on Friday warned that Americans need to worry about the changing profile of U. S. debt holders. Changing Profile Of Debt Holders In an opinion piece for the New York Times, Ngarmboonanant stated that the changing profile of U. S.