Critical Income Thresholds to Watch in Bonus Years
Income thresholds affected by bonus income — 2025 approximate levels
| Threshold | Approximate Level (2025) | What Happens When Crossed |
|---|---|---|
| 22% to 24% tax bracket | $103,350 (single) | Bonus income above this taxed at 24% instead of 22% |
| Additional Medicare Tax | $200,000 (single), $250,000 (MFJ) | Extra 0.9% on all wages above this |
| ACA subsidy cliff (400% FPL) | ~$60,240 (single), ~$124,800 (family of 4) | Excess premium tax credits must be repaid fully |
| Roth IRA phase-out begins | $150,000 (single), $236,000 (MFJ) | Roth IRA contribution limit begins phasing down |
| IRMAA Medicare premium surcharge | $106,000 (single), $212,000 (MFJ) | Higher Medicare Part B/D premiums for 2027 |
| Alternative Minimum Tax (AMT) | Varies widely by income/deductions | AMT may apply if regular deductions reduce tax below AMT threshold |
The ACA Subsidy Cliff: Biggest Risk for Many Earners
For individuals or families who receive ACA marketplace insurance subsidies (premium tax credits), crossing 400% of the federal poverty level can require full repayment of those credits at filing. A $5,000 bonus that pushes household income $100 above the 400% FPL threshold could require repaying thousands in subsidies. This is one of the most financially dangerous threshold crossings caused by bonuses.
Unlike tax bracket phaseouts that affect only the income above the threshold, the ACA subsidy repayment can require repaying the full excess subsidy if your income exceeds 400% FPL. Before accepting or spending a bonus that might push you across this level, calculate your exact MAGI including the bonus.
IRMAA: The Medicare Premium Surcharge for High Earners
IRMAA (Income-Related Monthly Adjustment Amount) increases Medicare Part B and Part D premiums for higher-income beneficiaries. The look-back period is two years — IRMAA for 2027 is based on your 2025 MAGI. A large bonus in 2025 could trigger higher Medicare premiums for two full years starting in 2027. For retirees or near-retirees, this is a significant consideration.
- IRMAA threshold: $106,000 (single) / $212,000 (MFJ) triggers first tier premium increase in 2025
- Higher income tiers: $133,000, $167,000, $200,000, $500,000 for single filers — each with higher surcharges
- Two-year look-back: 2025 income affects 2027 IRMAA premiums
- One-time income events: you can appeal IRMAA surcharges using Form SSA-44 for retirement or life-changing events
- Strategy: maximize 401(k) contributions to reduce MAGI below IRMAA thresholds when a bonus approaches the line
Using Pre-Tax Contributions to Stay Below Key Thresholds
The most practical tool for managing threshold crossing is maximizing pre-tax contributions before a bonus is processed. 401(k) contributions, HSA contributions, and NQDC plan deferrals all reduce your Modified Adjusted Gross Income (MAGI). For each threshold concern, calculate exactly how much pre-tax contribution is needed to keep your MAGI below the critical level.
Project Your Bonus Income vs Key Thresholds
Calculate your estimated annual income with and without your bonus to identify which thresholds you may cross.