A minority press release from the U.S. Senate Committee on Banking, Housing and Urban Affairs reports that Senators Elizabeth Warren and Jeanne Shaheen, the ranking members of the Senate Banking and Senate Foreign Relations committees, sent a letter to Treasury Secretary Scott Bessent and Secretary of State Marco Rubio seeking answers and greater transparency on the Trump Administration’s use of the Exchange Stabilization Fund (ESF) to support Argentina’s financial markets, involving more than USD 20 billion in taxpayer-backed resources. The letter argues that Treasury has not provided Congress or the public with meaningful details on the terms, conditions and safeguards for the support, including the terms of a USD 20 billion swap line with Argentina’s central bank and details on related ESF transactions. It also notes that Treasury has declined to release the agreement publicly on national security grounds, which the senators describe as a departure from past precedent, and cites disclosure requirements under the Gold Reserve Act and the Case–Zablocki Act. The lawmakers requested responses by January 9, 2026 and referenced prior efforts to scrutinise or limit the support, including proposed legislation and inquiries into reported New York Fed purchases of more than USD 2 billion of Argentine pesos on Treasury’s behalf.