If your taxable income in retirement falls below roughly $94,050 (for married couples filing jointly in 2026), you may owe absolutely nothing in federal taxes on long-term investment gains — that’s the 0% capital gains rate, and it’s one of the most powerful and most overlooked tax moves available to retirees today. Used wisely, this single strategy can let you sell appreciated stocks, mutual funds, or ETFs completely tax-free, reset your cost basis, and keep more of your own money working for you in the years ahead.

What exactly is the 0% capital gains rate?

When you sell an investment you’ve held for more than one year, the profit is called a long-term capital gain. The IRS taxes those gains at 0%, 15%, or 20%, depending on your income — not at your regular income tax rate. For 2026, the 0% bracket applies if your total taxable income (after deductions) stays at or below approximately $47,025 for single filers and $94,050 for married couples filing jointly. Many retirees living on a mix of Social Security, modest withdrawals, and dividends land right in this sweet spot without even realising it.

How do retirees actually use this strategy?

The move is sometimes called a “tax-gain harvest,” and here’s how it works in plain English. Suppose you bought shares in an index fund years ago for $10,000, and they’re now worth $25,000. Normally, selling would trigger a $15,000 taxable gain. But if your income this year keeps you inside the 0% bracket, you can sell those shares, pocket the gain tax-free, and immediately buy them back (unlike tax-loss harvesting, there’s no wash-sale rule on gains). Your new cost basis is $25,000, meaning future gains are smaller. You’ve essentially reset the clock — for free.

This strategy works best when you have a year with lower-than-usual income: perhaps you’ve delayed Social Security, you’re between jobs, or you’re in the early years of retirement before required minimum distributions (RMDs) kick in and push your income higher.

When should I claim Social Security to maximise my benefit?

Timing your Social Security claim is directly connected to this tax strategy. Every year you delay claiming Social Security past your full retirement age (66–67 for most people reading this), your benefit grows by about 8%. But those pre-claim years are also golden windows for tax-gain harvesting, Roth conversions, and other low-income maneuvers — because your taxable income is naturally lower. If you can afford to live on savings or part-time income while delaying Social Security until 70, you may create several years of 0% tax opportunity. The right answer depends on your health and finances, but the tax math often favors delay.

How much of Social Security is taxable?

Here’s something that surprises many retirees: up to 85% of your Social Security benefit can be taxable at the federal level, depending on your “combined income” (that’s your adjusted gross income, plus any tax-exempt interest, plus half your Social Security). If your combined income exceeds $34,000 as a single filer (or $44,000 for couples), up to 85% of benefits are taxable. This is exactly why managing your other income sources — like timing Roth conversions or capital gains — matters so much. Keeping combined income below those thresholds reduces the portion of Social Security that gets taxed.

What are the RMD rules for 2025 and 2026?

Required minimum distributions are the IRS-mandated withdrawals you must take from traditional IRAs and 401(k)s once you reach age 73. For 2025 and 2026, the rules remain the same: starting at 73, you must withdraw a calculated minimum each year based on your account balance and IRS life-expectancy tables. Miss an RMD and the penalty is 25% of the amount you should have taken (reduced to 10% if corrected quickly). RMDs count as ordinary income, which can push you out of the 0% capital gains bracket — another reason to do tax-gain harvesting before RMDs begin, while your income is still low.

How do I avoid Medicare IRMAA surcharges?

IRMAA stands for Income-Related Monthly Adjustment Amount — it’s a surcharge added to your Medicare Part B and Part D premiums if your income from two years ago exceeded certain thresholds. For 2026, if your 2024 income was above $106,000 (single) or $212,000 (married), you’re paying more than the standard Medicare Part B premium, which is $185.00 per month for 2026. Every large Roth conversion, big capital gain, or RMD spike can trigger or worsen an IRMAA surcharge. The fix: plan your income in advance, keep large one-time moves spread across multiple years, and appeal your IRMAA if your income has since dropped due to a life-changing event like retirement or divorce.

What is the Medicare Part B premium for 2025 and 2026?

The standard Medicare Part B premium for 2025 was $185.00 per month. For 2026, it has risen to $185.00 — check Medicare.gov for the most current figures as these can adjust annually. Because IRMAA surcharges are layered on top of the base premium, a single year of high income can cost a couple thousands of dollars extra in Medicare costs two years later. This is known as the “two-year lookback,” and it’s one more reason why keeping your taxable income below key thresholds in your early retirement years pays dividends for years to come.

Putting it all together: your 0% tax action plan

Here’s a simple checklist to see if this strategy applies to you right now:

  • Estimate your 2026 taxable income. Add up Social Security (the taxable portion), IRA withdrawals, pension income, dividends, and other income — then subtract your standard deduction.
  • Check your bracket. If the result is below $47,025 (single) or $94,050 (married filing jointly), you may be in the 0% capital gains zone.
  • Identify appreciated investments in taxable brokerage accounts (not IRAs — those have different rules).
  • Calculate how much gain you can harvest without crossing into the 15% bracket.
  • Sell and repurchase to reset your cost basis — and consider whether a Roth conversion could fill any remaining room in the bracket.
  • Confirm IRMAA impact by checking whether the extra income will affect your Medicare premiums two years from now.

A fee-only financial planner or CPA can run these numbers precisely, but even a rough estimate can reveal surprisingly large tax savings hiding in plain sight.

FAQ

Frequently Asked Questions

When should I claim Social Security to maximise my benefit?

Delaying Social Security past your full retirement age (66–67 for most people) increases your monthly benefit by approximately 8% per year, up to age 70. If you’re in good health and can cover expenses from savings in the meantime, waiting until 70 typically produces the highest lifetime benefit — and creates low-income years ideal for tax-gain harvesting or Roth conversions.

How much of my Social Security income is taxable?

Up to 85% of your Social Security benefit can be subject to federal income tax if your combined income (AGI plus tax-exempt interest plus half your Social Security) exceeds $34,000 for single filers or $44,000 for married couples. Managing other sources of income carefully — such as timing capital gains and IRA withdrawals — can reduce how much of your benefit gets taxed.

What are the RMD rules for 2025 and 2026?

For both 2025 and 2026, required minimum distributions from traditional IRAs and 401(k)s must begin at age 73, calculated using IRS life-expectancy tables applied to your prior year-end balance. Missing an RMD triggers a 25% penalty on the amount not withdrawn, reduced to 10% if corrected promptly. RMD income counts as ordinary income and can affect your tax bracket and Medicare premiums.

How do I avoid Medicare IRMAA surcharges?

IRMAA surcharges are triggered when your income from two years prior exceeds $106,000 (single) or $212,000 (married), causing your Medicare Part B and Part D premiums to rise significantly above the standard rate. You can avoid or reduce IRMAA by planning large income events — like Roth conversions or capital gains harvests — carefully across multiple years, and by filing an appeal if your income has dropped due to retirement, divorce, or another qualifying life event.

What is the Medicare Part B premium for 2025 and 2026?

The standard Medicare Part B premium was $185.00 per month in 2025, with 2026 rates subject to annual adjustment by the Centers for Medicare & Medicaid Services — check Medicare.gov for the latest confirmed figure. Higher-income beneficiaries pay additional IRMAA surcharges on top of the base premium, which is determined by income reported on your tax return from two years earlier.