A lot of people assume their tax bill will shrink once they stop working. And in some cases, it does. But retirement also introduces a new set of tax rules that didn't apply during your career — and if you're not aware of them, they can add up fast.
Withdrawals from retirement accounts, Social Security taxation, Medicare premium surcharges, and investment income taxes don't operate in isolation. They interact with each other in ways that can push your effective tax rate higher than you'd expect. The good news is that most of these traps are avoidable with proactive planning. Here are five of the most common ones.
The Social Security "Tax Torpedo"
Many retirees assume their Social Security benefits are tax-free. They're not — at least not entirely. Depending on your income, up to 85% of your benefits may be subject to federal income tax.
The IRS determines this using something called provisional income, which includes your adjusted gross income, any tax-exempt interest, and half of your Social Security benefits. For married couples filing jointly, benefits can start becoming taxable once provisional income crosses $32,000, and up to 85% becomes taxable above $44,000.
Where it gets complicated is the interaction with traditional retirement account withdrawals. Every dollar you pull from a Traditional IRA or 401(k) increases your provisional income — which can simultaneously trigger taxes on that withdrawal and cause more of your Social Security to become taxable. This compounding effect is what people call the "tax torpedo."
A retiree who withdraws $10,000 from an IRA may not just owe tax on that $10,000. The withdrawal could also push several thousand dollars of Social Security benefits into taxable territory — creating a higher effective tax rate than expected.
Without modeling these interactions inside a detailed retirement plan, it's easy to trigger higher taxes without realizing it.
IRS reference: Social Security Benefits · SSA reference: Taxes and Your Benefits
The Net Investment Income Tax (NIIT)
If your modified adjusted gross income exceeds $200,000 (single) or $250,000 (married filing jointly), certain investment income gets hit with an additional 3.8% surtax. For investors already in the 20% long-term capital gains bracket, that brings the federal rate to 23.8% before state taxes.
The NIIT applies to capital gains, dividends, interest income, rental income, and passive business income. What surprises many retirees is how broadly it reaches:
- Brokerage account portfolios
- Bank accounts and CDs
- Rental properties
- Home sale gains above the primary residence exclusion ($250,000 single / $500,000 married)
Some income sources are exempt — Social Security, municipal bond interest, and retirement account withdrawals don't count toward the NIIT directly. But they do increase your MAGI, which can push your other investment income over the threshold.
A large IRA withdrawal might not itself be subject to the NIIT — but it could raise your MAGI enough that your dividend and capital gains income suddenly is.
IRS reference: Net Investment Income Tax
Medicare IRMAA Surcharges
Taxes aren't the only costs tied to retirement income. Higher-income retirees face something called IRMAA — Income-Related Monthly Adjustment Amounts — which increases your Medicare Part B and Part D premiums based on income from two years prior.
What makes IRMAA particularly tricky is that the thresholds operate like cliffs. A relatively small increase in income can push you into the next premium bracket for the entire year. Income that can trigger IRMAA includes:
- Required Minimum Distributions
- Capital gains from investments
- Roth conversions
- Real estate or business sales
For retirees managing withdrawals across multiple accounts, these surcharges can quietly add thousands of dollars in annual healthcare costs — costs that don't show up on a tax return but absolutely affect your bottom line.
SSA reference: Medicare Part B Costs
Required Minimum Distributions
If you have a traditional retirement account, at some point the IRS will require you to start taking money out — whether you need it or not. Under current law, RMDs generally begin at age 73 (rising to 75 for younger generations) and apply to Traditional IRAs, 401(k)s, SEP IRAs, and SIMPLE IRAs.
The required amount is based on IRS life expectancy tables, and it increases as a percentage of the account each year. For retirees with significant savings, this can add up quickly.
A retiree with $1.5 million in traditional retirement accounts would have an initial RMD of roughly $56,000 at age 73. As the years go on, that number grows.
Large RMDs don't just create a tax bill on their own — they can stack on top of Social Security income, push you into a higher bracket, trigger IRMAA surcharges, and bring investment income into NIIT territory all at once. This is exactly why tax diversification across account types matters so much heading into retirement.
IRS reference: Required Minimum Distributions
The Tax-Deferred Illusion
There's a reason tax-deferred accounts are so popular — contributions reduce your taxable income today, and investments grow without being taxed each year. But tax-deferred is not the same as tax-free. The bill is coming. The question is when, and who's paying it.
This becomes especially relevant for estate planning. Under the SECURE Act, most non-spouse beneficiaries must withdraw an inherited retirement account within 10 years. Those withdrawals are generally taxed as ordinary income.
A $1 million inherited IRA spread evenly over 10 years means roughly $100,000 in annual withdrawals. If your beneficiary is in their peak earning years, that income stacks on top of their salary — potentially pushing them into a significantly higher bracket.
In other words, the taxes deferred during the original owner's lifetime don't disappear. They often get transferred to the next generation at an even higher rate. This dynamic comes up often in retirement planning conversations, and it's worth thinking through before it becomes someone else's problem.
IRS reference: Retirement Topics — Beneficiary
How to Plan Around Them
The goal of tax planning in retirement isn't to minimize taxes in any single year — it's to manage the total tax burden across your entire retirement timeline. Here are four strategies that help.
Strategic Roth Conversions
Moving assets from a Traditional IRA into a Roth IRA means paying tax now — but future growth and qualified withdrawals are tax-free. Conversions are often most effective in the early years of retirement, before Social Security and RMDs begin adding to your income. Done carefully, they can reduce future RMDs, lower lifetime taxes, and leave a more tax-efficient inheritance for your heirs.
Tax-Loss Harvesting
Selling investments that have declined in value lets you realize a capital loss, which can offset capital gains or up to $3,000 of ordinary income per year. Excess losses carry forward to future years. This strategy is particularly useful for managing exposure to capital gains taxes and the NIIT.
Managing Withdrawal Order
The traditional sequence — taxable accounts first, then tax-deferred, then Roth — isn't always optimal. A proportional withdrawal strategy draws from all three buckets intentionally, keeping you in lower tax brackets, reducing future RMDs, and managing Social Security taxation over time.
Coordinating Income Sources
Most retirees have multiple income streams — Social Security, pension, retirement account withdrawals, brokerage investments, rental income. Coordinating when and how much you draw from each can help manage bracket exposure and avoid crossing IRMAA or NIIT thresholds. A good retirement plan models these interactions over decades, not just year to year.
The Bottom Line
None of the five traps covered here are inherently harmful. They're just rules — and like any rules, they can be planned around. The problem is that most people don't discover them until they're already in retirement, at which point the options narrow.
- Social Security taxation and the "tax torpedo"
- The Net Investment Income Tax (NIIT)
- Medicare IRMAA surcharges
- Required Minimum Distributions
- The tax-deferred illusion and inherited accounts
A well-structured retirement plan accounts for all of these moving parts — not just in isolation, but as a system. The retirees who manage taxes most effectively aren't necessarily the ones who earn the least. They're the ones who plan the most deliberately.
At Voyage, tax efficiency is built into every retirement plan we create. If you'd like to talk through how these rules might affect your specific situation, we're happy to start a conversation.
This article is for informational and educational purposes only and should not be construed as personalized investment, tax, or legal advice. The strategies discussed may not be appropriate for all individuals. Readers should consult with qualified financial, tax, or legal professionals before making decisions related to their financial situation. Past performance is not indicative of future results. All investments involve risk, including the potential loss of principal.