The 79% market-implied probability of no further US sovereign credit rating downgrade before 2027 is driven primarily by the stable outlooks assigned by Moody’s, S&P, and Fitch following Moody’s May 2025 one-notch cut to Aa1, which aligned all three major agencies at AA+/Aa1 levels. Persistent fiscal deficits and debt-to-GDP ratios above 120%—with the Congressional Budget Office projecting continued primary shortfalls near $1.9 trillion for fiscal 2026—have already been incorporated into current ratings without triggering negative watches. Absent acute political shocks, debt-ceiling standoffs, or abrupt fiscal policy reversals since mid-2025, rating agencies have maintained stable outlooks, supporting trader consensus that another downgrade is unlikely over the next 18 months despite elevated interest costs and structural debt dynamics.