The Internal Revenue Service attributed $6.5 billion in revenue to its examination function in fiscal 2025, down 35% from the previous year, as enforcement staffing fell sharply, according to the Treasury Inspector General for Tax Administration. Employees in the IRS Examination and Collection functions declined from 27,217 in fiscal 2024 to 19,612 in fiscal 2025 and 17,517 as of Jan. 10, 2026. Examination starts fell 30%, including a 27% decline for taxpayers reporting more than $400,000 in income. Large-corporation examination starts rose 7% from fiscal 2023 to fiscal 2025, reaching 1,491, while partnership starts fell 76% to 1,589 from 6,709. The IRS also issued 3.16 million nonfiler notices in fiscal 2025, compared with none in fiscal 2023. Collection-function revenue rose 17% from fiscal 2023 to fiscal 2025 as automated notices resumed after pandemic-related pauses. Total federal tax revenue paid to the IRS increased 4.2% to $5.3 trillion. TIGTA said staffing losses challenge taxpayer service and enforcement, while IRS officials cited artificial intelligence and advanced analytics as tools for identifying noncompliance. The report made no recommendations.