Most people believe double taxation is something that only happens to corporations or people with extremely complex finances.
In reality, double taxation is one of the most common and expensive retirement planning mistakes we see, and it often happens to people who are doing everything “right.” They work with an accountant, they file on time, and they follow the rules. Yet they still end up paying tax twice on the same dollar, simply because no one was coordinating the full retirement picture.
This article explains how double taxation happens, why it’s easy to miss, and why retirement planning plays a different role than tax preparation.
Double taxation occurs when the same income, asset, or transaction is taxed more than once, not because of an IRS penalty, but because of reporting gaps or missed credits.
These issues rarely show up as errors. They show up as higher-than-necessary tax bills that quietly compound over time. And the IRS doesn’t mind you paying more! It’s our goal to pay the IRS no more than is legally necessary.
Qualified Charitable Distributions allow individuals over age 70 to donate directly from an IRA to a qualified charity, excluding that amount from taxable income. It also counts toward the individual’s RMD, solving a few problems at once.
The problem is reporting. Most custodians do not identify QCDs clearly on Form 1099-R. To the IRS, it often looks like a normal taxable IRA distribution.
If your tax preparer is not explicitly told that a distribution was a QCD, your preparer will see the 1099-R and will put the number in the box into their tax software, and your preparer will move on. The issue is that the 1099-R has a single number on it - the total taxable income from distributions from your IRA. Even though the custodian has a record of your QCD going directly from the custodian to your charity, they still do not signal that on your 1099-R. Only if you tell your tax preparer to enter part (or all) of your RMD into the tax software as a QCD will you get the benefit. By default, all of your distributions are taxable. Only with proper reporting will your QCD be granted tax-free status.
Restricted Stock Units (RSUs) and stock options are another frequent source of double taxation, especially for people coming out of corporate or executive roles.
Here’s how it typically happens:
RSUs vest, and some shares are sold automatically to cover withholding
The value of the vested shares is added to your W-2 income
Later, you sell the remaining shares
The brokerage issues a 1099-B showing a zero cost basis
Cost basis is a fancy word for “how much you paid.” That number is important because the IRS wants to be fair; if you bought shares with money on which you already paid tax (in this case, your W-2 includes the money you paid for the shares), you shouldn’t pay tax on that money again! They only want to tax you on how much additional money you earned from your investment. When your cost basis is reported as zero, you’ll be taxed on your gains and the amount of money you paid to get the investment.
The brokerage isn’t wrong; it just doesn’t know the shares were already taxed as wages.
If the basis is not adjusted:
You pay tax when the shares vest
You pay tax again when they’re sold
This is one of the most overlooked issues of double taxation we encounter in retirement planning.
For families with larger estates, double taxation can occur across generations.
When estate taxes are paid on a traditional IRA:
The estate may pay up to 40% in estate tax (plus some states add additional estate tax)
The beneficiary later withdraws funds and pays income tax
What’s often missed is that heirs may be eligible for a deduction related to estate taxes already paid on the IRA.
If that deduction isn’t claimed:
The same IRA dollars are taxed twice
Once at the estate level
Again as income to the beneficiary
This mistake often goes unnoticed because the time to claim this deduction is when the heir distributes money from the IRA, not at the time of inheriting the IRA. These distributions can happen immediately or up to decades after, depending on who is inheriting the IRA. Without that knowledge, the heir gets double-taxed.
Most homeowners are familiar with the capital gains exclusion on the sale of a primary residence, up to $500,000 for married couples and $250,000 for individuals.
What’s less understood is how capital improvements affect your tax bill.
Capital improvements such as:
Additions
Major renovations
Structural upgrades
Can be added to your home’s cost basis, reducing taxable gain. Every documented improvement can reduce taxes by as much as 23.8% at the federal level.
When receipts are lost or never shared with a tax preparer:
Basis is understated
Gain is overstated
Taxes are higher than necessary
The reason this isn’t so clear to most is because when reporting things to your CPA, there is no place on a tax return to increase the basis of your personal residence; information related to capital improvements often gets ignored because it’s not an investment property (which would have basis tracked on a tax return). Therefore, the time to inform the accountant about these capital improvements is when you have sold the house and are reporting the sale on your tax return.
State taxation is another area where people are often surprised.
If you: Live in one state OR Work or earn income in another, then your income may be taxed by both states unless the proper credits for taxes paid to other states are applied.
If those credits are missed:
You pay tax twice on the same income
The state will gladly take your extra money
This is especially common during:
Final working years
Consulting arrangements
Partial retirement
There are many other ways double taxation can occur, including:
Missed elections
Not understanding state rules and deductions well enough
Poor withdrawal sequencing
Timing issues between income sources
Misaligned beneficiary strategies
The examples above highlight why retirement planning is less about tax tricks and more about mistake prevention. Ultimately, tax preparation and retirement planning serve different roles.
A CPA reports what has already happened and focuses on accuracy and compliance. A retirement planner, on the other hand, looks ahead and coordinates decisions across years, accounts, and benefits.
Double taxation typically happens in the space between forms, where no single document tells the whole story. That’s why retirement planning focuses on eliminating issues before they appear on a tax return.
Most people don’t come to us asking how to pay the least tax this year.
They come because they want confidence that they aren’t overpaying, they aren’t making irreversible mistakes, and their decisions actually work together.
Double taxation is rarely obvious. But once it happens, it’s expensive—and often permanent. Retirement planning exists to eliminate these risks before they compound.
If you’re approaching retirement and want confidence that your decisions are working together, not quietly working against you, a conversation can help.
Charles Culver, Founder of Martello Retirement & Wealth, works with people to identify where double taxation and coordination gaps tend to hide, and how to eliminate them before they become permanent.
There’s no product pitch and no pressure, just a thoughtful review of the decisions ahead and the risks worth addressing.
Double taxation occurs when the same income or asset is taxed more than once due to reporting gaps, missed credits, or poor coordination between accounts, institutions, or tax years. This can happen at any time, and happens to many people every year. At Martello, we focus on identifying where these overlaps commonly occur and eliminating them before they appear on a tax return.
The most common mistake is making withdrawal and timing decisions in isolation, such as withdrawing funds from the wrong account, claiming Social Security without tax coordination, or inadvertently triggering higher Medicare premiums. These mistakes often aren’t obvious until years later.
Yes. While no strategy eliminates taxes entirely, thoughtful retirement planning can help reduce unnecessary lifetime taxes by coordinating income sources, timing distributions strategically, and identifying planning opportunities before they disappear.
Yes. Many cases of double taxation happen even when taxes are filed accurately and on time. The issue isn’t a filing error, it’s missing context. If a tax preparer isn’t aware of how income was previously taxed or how different accounts interact, the same dollar can be taxed twice without raising red flags. Retirement planning helps surface that context, so filing reflects the full picture.
Social Security benefits may become partially taxable depending on your overall income. When combined with investment income, withdrawals, or part-time work, Social Security can push retirees into higher effective tax brackets if not coordinated properly within a retirement plan.
A CPA plays a critical role in compliance and accuracy, but their work is typically backward-looking. They report what has already happened based on the information they receive.
Martello’s role is complementary. We help ensure the right information exists in the first place by coordinating decisions across years, accounts, and benefits, so your CPA has what they need to file accurately.
Some of the most common issues include:
Qualified Charitable Distributions are not being identified properly
RSUs and stock options with incorrect cost basis
Estate taxes and inherited IRA deductions are being missed
Capital gains overstated due to missing home improvement records
Income taxed by multiple states without proper credits
These aren’t edge cases; they’re situations we see regularly when retirement planning hasn’t been coordinated.
Retirement planning focuses on timing, sequencing, and coordination. By understanding when income is created, where it comes from, and how it affects taxes, Medicare, and benefits, planning helps prevent mistakes that only become visible years later.
At Martello, we pressure-test decisions before they’re implemented, so potential double taxation issues are addressed early.
Yes. While some scenarios apply to larger estates, many double taxation issues affect everyday people, especially those with IRAs, employer stock, charitable giving goals, or multi-state income.
Avoiding double taxation isn’t about complexity or wealth level; it’s about coordination.
Martello doesn’t replace your CPA or prepare your tax return. Instead, we act as a guide, helping ensure retirement decisions are coordinated so avoidable tax issues don’t arise in the first place.
Our focus is on eliminating unnecessary risk, aligning decisions with your long-term goals, and helping your plan work as intended over time.
Martello Retirement and Wealth, LLC is a Registered Investment Adviser. For more information about our firm, including our services, fees, and conflicts of interest, please refer to our Form ADV Part 2A, available on our website at https://www.martelloretirement.com/l/adv.
This content is for informational and educational purposes only and is not intended to provide specific tax, legal, or investment advice. Tax laws are complex and subject to change. Always consult with a qualified tax professional or attorney regarding your specific situation before making any tax-related or estate-planning-related decisions.
Past performance or hypothetical scenarios are not indicative of future results.
There are no guarantees that any tax or estate planning strategies discussed will achieve specific outcomes or avoid future tax liabilities.
The information provided is general in nature and does not consider your individual circumstances, financial goals, or needs. Personalized financial or tax advice can only be provided after a comprehensive understanding of your personal situation.
Unless expressly stated otherwise, any tax advice contained in this communication is not intended or written to be used, and cannot be used, for the purpose of avoiding penalties under the Internal Revenue Code.