THE HORIZON
A Tuesday morning in March 2041. A 61-year-old realizes, three weeks late, that he forgot to take his required distribution from an inherited IRA.
He opens the penalty notice expecting to lose half of what he should have withdrawn. Instead the letter cites a corrected penalty of 10 percent, filed and paid within the window.
That smaller number traces back to a rule finalized years earlier, one item in a long list most people scrolled past. A summary published this week laid out exactly what changed and why it still matters.
THE EVENT
On September 29, 2025, CPA Practice Advisor published a roundup detailing ten changes to 401(k) and IRA rules stemming from the SECURE 2.0 Act, several of which phased in during 2025. The summary consolidated provisions that had rolled out gradually since the law's original passage.
Among the changes: the penalty for a missed required minimum distribution dropped from 50 percent of the shortfall to 25 percent, and to 10 percent if corrected within a defined window after filing an amended return. Previously, a missed RMD carried one of the harshest penalties in the tax code.
Owners of Roth 401(k) accounts no longer face required minimum distributions during their lifetime, aligning the rule with the treatment Roth IRAs have always received. Newly established 401(k) and 403(b) plans must now automatically enroll eligible employees at a minimum 3 percent contribution rate.
Catch-up contribution limits also rose for workers age 60 through 63, allowing larger annual additions to workplace retirement plans than what is available to younger savers. The IRS confirmed these figures apply for the 2025 plan year.
THE PATH
The first consequence changes how much risk an inherited IRA carries for anyone managing one on behalf of aging parents. A shortfall on a $40,000 required distribution once meant a $20,000 penalty; under the new tiered structure, a corrected error costs closer to $4,000.
That gap changes the math on whether to hire a professional to track distribution deadlines or handle it manually, since the downside of a mistake is now smaller than the annual fee some advisers charge for that single task.
The second consequence sits in the Roth 401(k) itself. Removing lifetime RMDs means a 45-year-old directing new contributions toward a Roth 401(k) rather than a traditional one can let that balance compound uninterrupted for as long as he lives, rather than being forced to draw it down starting at 73.
On a $400,000 Roth 401(k) balance growing at 7 percent annually, skipping ten years of forced withdrawals leaves roughly $200,000 more invested and compounding than the same balance under the old rule.
The third, less obvious consequence touches business capital for anyone who owns a small company and just started a 401(k) plan. Mandatory auto-enrollment at 3 percent raises the plan's average participation rate, which improves the plan's nondiscrimination testing and can let the owner himself contribute more without triggering a refund of excess contributions.
A business owner who previously capped his own deferrals because participation ran too low may now be able to defer closer to the full $23,500 limit once auto-enrollment lifts average employee participation.
The fourth consequence reaches into the years right before retirement. A 61-year-old builder using the higher catch-up contribution limit for ages 60 through 63 can direct several thousand additional dollars a year into a 401(k), money that otherwise would have landed in a taxable brokerage account and faced capital gains tax on withdrawal.
Over four years, that catch-up window alone can add tens of thousands of dollars to a balance that also grows tax-deferred rather than being taxed annually on dividends and realized gains.
THE WATCH
Watch for the IRS's annual notice on 2026 contribution and catch-up limits, typically released in November, since it confirms whether these figures rise further next year. Plan administrators must also update auto-enrollment defaults for any newly established plans going forward.
Also worth confirming with a plan administrator: whether an existing 401(k) has adopted the Roth RMD change automatically or requires an account holder to update beneficiary and distribution elections manually.
A builder now knows a paperwork mistake on an inherited account costs a fraction of what it used to. That single change alone justifies rereading a decade-old estate plan built around the harsher rule.
Sources
10 Big Changes to Retirement Accounts Under New 401(k) and IRA Rules, CPA Practice Advisor: https://www.cpapracticeadvisor.com/2025/09/29/10-big-changes-to-retirement-accounting-under-new-401k-and-ira-rules/169767/
SECURE Act 2.0: What the legislation could mean for you, Fidelity: https://www.fidelity.com/learning-center/personal-finance/secure-act-2