The Single Biggest IRA Mistake That Could Cost Your Heirs Millions, According to Experts

The Critical Oversight: Why Beneficiary Forms Trump Your Will

Millions of Americans rely on Individual Retirement Accounts (IRAs) as the cornerstone of their retirement security. However, financial and estate planning experts consistently warn that one simple, often-overlooked administrative detail represents the single biggest and most expensive mistake an IRA holder can make: improper or outdated beneficiary designations.

According to leading estate planning attorneys, failing to correctly name and update beneficiaries on your IRA paperwork can derail even the most meticulously crafted estate plan, potentially subjecting your assets to costly probate and eliminating crucial tax advantages for your heirs.

A person reviewing and signing IRA beneficiary designation forms with a pen.
IRA beneficiary forms are legally binding contracts that dictate who receives the assets, overriding instructions in a general will. Image for illustrative purposes only. Source: Pixabay

Why the Beneficiary Form Trumps Your Will

Many people assume that their last will and testament dictates who inherits their IRA assets. This is a dangerous misconception. IRAs, along with 401(k)s, life insurance policies, and annuities, are considered non-probate assets. They are governed by contract law, meaning the financial institution holding the account is legally bound to pay the assets directly to the person(s) named on the specific beneficiary form on file.

This means that if you name your ex-spouse on the IRA form, but your will names your current spouse, the ex-spouse will receive the funds. The IRA form is the controlling document.

“The biggest mistake we see is the failure to coordinate the beneficiary designations with the overall estate plan,” explains one attorney. “If the beneficiary form is blank, outdated, or names the wrong person, the consequences are immediate and often irreversible.”


The High Cost of Neglect: When IRAs Go to Probate

The most severe consequence of neglecting the beneficiary form is when the designation is left blank, or if all named beneficiaries predecease the account owner. In these scenarios, the IRA assets typically default to the owner’s estate.

When an IRA is paid to the estate, several costly problems arise:

  • Probate: The assets must go through the public, often lengthy, and expensive probate process, delaying access to funds for heirs.
  • Tax Inefficiency: The estate may be subject to higher tax rates, and the beneficiaries lose the ability to utilize the tax-advantaged stretch provisions that allow inherited IRAs to grow tax-deferred over time (or, post-SECURE Act, over the 10-year period).
  • Creditor Exposure: Assets held within an estate are generally exposed to the decedent’s creditors, potentially reducing the amount passed to heirs.

The Need for Contingent Beneficiaries

A common error is naming only a primary beneficiary. Experts stress the absolute necessity of naming contingent beneficiaries. These individuals or entities inherit the assets only if the primary beneficiary has died. Without a contingent designation, if the primary heir passes away first, the assets are likely directed back to the estate, triggering the negative consequences outlined above.


Navigating the SECURE Act: The 10-Year Rule

The rules governing inherited IRAs became significantly more complex with the passage of the Setting Every Community Up for Retirement Enhancement (SECURE) Act in 2020. This legislation eliminated the traditional “stretch IRA” for most non-spouse beneficiaries.

Under the SECURE Act, most non-spouse beneficiaries (known as non-eligible designated beneficiaries) are now required to withdraw all inherited IRA funds within 10 years following the original owner’s death. This accelerated timeline can result in substantial tax bills for heirs who are in their peak earning years.

Proper beneficiary planning is now more critical than ever to ensure assets are distributed to the right individuals or trusts that can handle the new 10-year withdrawal requirement effectively.

Close-up of trust and estate planning documents, highlighting the complexity of financial transfers.
The SECURE Act of 2020 fundamentally changed the tax landscape for inherited IRAs, making careful beneficiary designation a high-stakes decision. Image for illustrative purposes only. Source: Pixabay

Who is Exempt from the 10-Year Rule?

The SECURE Act carves out exceptions for Eligible Designated Beneficiaries (EDBs) who can still utilize the old “stretch” rules (taking distributions based on their life expectancy). EDBs include:

  • Surviving spouses.
  • Minor children of the IRA owner (until they reach the age of majority).
  • Disabled or chronically ill individuals.
  • Individuals who are not more than 10 years younger than the IRA owner.

Essential Steps for Reviewing Your IRA Beneficiaries

To safeguard your retirement savings and protect your heirs from costly mistakes, financial professionals recommend a thorough review of all retirement accounts at least once every three years, and immediately following any major life change.

Here are the critical steps to ensure your IRA designations are correct and aligned with your estate plan:

  1. Locate the Forms: Obtain the most recent beneficiary forms directly from your IRA custodian (brokerage firm or bank). Do not rely solely on memory or old paperwork.
  2. Verify Primary and Contingent Names: Ensure both primary and contingent beneficiaries are clearly named. Use full legal names and Social Security numbers if required by the custodian.
  3. Address Major Life Changes: Review designations immediately after marriage, divorce, birth of a child, or the death of a named beneficiary. Divorce decrees often mandate changes, but the IRA custodian must receive the updated form to make it official.
  4. Define Distribution Method: Clearly specify how assets should be divided, typically using per stirpes (by branch of the family) or per capita (by head, equally among named individuals) to handle situations where a beneficiary predeceases you.
  5. Consider Trusts: If you have minor children, special needs beneficiaries, or complex tax situations, consult an estate attorney about naming a trust as the beneficiary. This requires specific, careful drafting to ensure the trust qualifies for the best possible tax treatment under the SECURE Act.

Key Takeaways and Actionable Steps

The attorney’s warning underscores that administrative diligence is as important as investment strategy when it comes to retirement accounts. The key takeaway is that the IRA beneficiary form is a legally binding contract that supersedes your will.

  • The Biggest Mistake: Neglecting to update or properly complete the IRA beneficiary designation form.
  • The Consequence: Assets may be forced into probate, losing tax-deferred growth and exposing the funds to creditors.
  • Immediate Action: Verify both primary and contingent beneficiaries on all retirement accounts (IRAs, 401(k)s, etc.).
  • SECURE Act Impact: Understand that most non-spouse heirs must now liquidate the inherited IRA within 10 years, making proper planning crucial to managing tax burdens.

Conclusion

While the concept of reviewing paperwork might seem tedious, the financial stakes are enormous. A few minutes spent verifying and updating your beneficiary forms today can save your heirs months of legal hassle and potentially hundreds of thousands of dollars in unnecessary taxes and probate fees. Given the complexities introduced by the SECURE Act, consulting a qualified financial advisor or estate planning attorney is highly recommended to ensure your retirement legacy is protected and distributed exactly as intended.

Disclaimer: This article is for informational purposes only and does not constitute financial, legal, or tax advice. Readers should consult with qualified professionals regarding their specific financial and estate planning needs.

Source: CNBC

Original author: Kate Dore, CFP®, EA

Originally published: November 9, 2025

Editorial note: Our team reviewed and enhanced this coverage with AI-assisted tools and human editing to add helpful context while preserving verified facts and quotations from the original source.

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