This bill grants the Secretary of the Treasury the authority to direct the Federal Deposit Insurance Corporation (FDIC) and the National Credit Union Administration (NCUA) to establish emergency transaction account guarantee programs . These programs are designed to fully insure deposits held in non-interest-bearing transaction accounts at insured depository institutions and credit unions during times of significant financial instability. Activation of such a program requires a determination by the Secretary of the Treasury, in consultation with the President, that a "banking stress event" or "credit union stress event" exists. This event must present serious adverse effects on economic conditions or the stability of the respective financial system, and the program must be deemed necessary to avoid or mitigate these effects. The bill imposes strict limitations on these emergency programs. The Secretary must determine a maximum cost for the program, which can only be increased with further approval and a report to Congress. Furthermore, each program is limited to an initial duration of six months, with a single possible extension for an additional three months, also requiring approval and a congressional report. To ensure accountability, the Secretary of the Treasury is required to testify before Congress within 30 days of a program's establishment. Additionally, the Government Accountability Office (GAO) must review the program and report its findings to Congress within 90 days of its termination. Any losses incurred by the Deposit Insurance Fund or the National Credit Union Share Insurance Fund due to these guarantees would be recovered through special assessments on insured financial institutions.