IRMAA (Income-Related Monthly Adjustment Amount) was enacted in 2003 and implemented in 2007. For single filers, the lowest threshold (where surcharges begin) remained fixed at (based on 2-year prior income) until 2019, but inflation indexing started in 2020, with the 2026 threshold reaching 109000.
Key Historical Thresholds for Single Filers (Lowest Tier):
- 2007–2019: 85000
- 2020: 87000
- 2021:
88000 - 2022: 91000
- 2023: 97000
- 2024: 103000
- 2025: 106000
- 2026: 109000
Important Context:
- Calculation: IRMAA is based on your Modified Adjusted Gross Income (MAGI) from two years prior.
- Income Type: Included in MAGI are capital gains, which can trigger the surcharge.
- Evolution: Originally only for Part B, it expanded to Part D in 2011. The threshold for paying higher premiums remained stagnant for over a decade before adjusting annually for inflation starting in 2020.
2026年的各个tiers可查“2026 IRMAA”。
