What Is IRC 401? 2026 Limits, SECURE 2.0, and Distributions

Internal Revenue Code Section 401 is the federal statute that sets the rules for IRC 401 qualified retirement plans, meaning employer-sponsored plans that earn favorable tax treatment by meeting a specific set of federal requirements. When a plan qualifies, contributions grow tax-deferred inside the plan’s trust, the employer deducts what it puts in, and participants delay income tax until they actually take money out. Miss even one requirement and the plan can lose that status, with tax consequences that hit the employer, the trust, and every participant at once.

What Counts as a Qualified Plan

Section 401 covers three categories: pension plans, profit-sharing plans, and stock bonus plans. Within those, the practical divide is between defined benefit and defined contribution plans, and that structural choice drives almost everything else.

A defined benefit plan is the traditional pension. The employer promises a specific monthly payment in retirement, usually tied to salary history and years of service, and takes on the investment risk of funding those promises. These have thinned out in the private sector because the funding obligations are expensive and unpredictable, but they remain common in government employment.

A defined contribution plan flips the arrangement. You and your employer contribute to an individual account in your name, and your eventual benefit depends on how much went in and how the investments performed. The 401(k) is the familiar version, letting you defer part of your paycheck before income taxes are calculated. Technically, a 401(k) isn’t a separate plan type; it’s a cash-or-deferred feature attached to a profit-sharing or stock bonus plan.¹

Every qualified plan must be permanent and ongoing, not a short-term tax vehicle. It also has to exist as a written document covering eligibility, contributions, vesting, and distributions. That document is the plan’s legal backbone; every operational decision has to trace back to it.

The Core Qualification Rules

Section 401(a) contains more than 30 requirements a plan has to satisfy every year. Four categories account for most of the trouble sponsors run into.

Nondiscrimination

A plan can’t tilt benefits toward the top of the org chart. Under Section 401(a)(4), contributions or benefits can’t discriminate in favor of highly compensated employees, defined for 2026 as workers who earned more than $160,000 in the prior year.¹² Plans run annual tests comparing participation and contribution rates between the two groups. Failing doesn’t automatically end the plan, but it does force corrective action, usually returning excess contributions to higher-paid workers or making additional contributions for everyone else.

Vesting

Vesting is when employer money becomes permanently yours. Your own deferrals vest immediately at 100%, but the employer can put a schedule on its match and profit-sharing contributions. Section 401(a)(7) sets the minimum standards.¹ Cliff vesting jumps you from 0% to 100% after a set number of years; graded vesting phases ownership in over time. Leave before you’re fully vested and the unvested piece goes back to the plan as a forfeiture.

Top-Heavy Testing

A plan turns “top-heavy” when key employees hold more than 60% of the plan’s assets.³ Key employees include officers earning more than $235,000 in 2026, anyone owning at least 5% of the company, and 1% owners earning above $150,000.² When a plan tips over, it has to give non-key employees minimum contributions or benefits and apply faster vesting. Small businesses with a handful of highly paid owners and many lower-paid workers run into this constantly.

Documentation and Disclosure

The formal plan document is the authority the IRS reads during an audit, and operating outside it is one of the most common failures. Sponsors also have to give every participant a summary plan description in plain language, delivered within 90 days of coverage starting.⁴

Fiduciary Duties

Anyone with control over plan assets or administration is a fiduciary under ERISA, held to a demanding standard. Fiduciaries must act only in the interest of participants and beneficiaries. The statute imposes four duties:⁵

Prudence, meaning care and skill of a knowledgeable professional and a documented decision-making process.
Loyalty, meaning every decision is for providing benefits and paying reasonable plan expenses, not for the employer’s benefit.
Diversification, meaning investments are spread to minimize the risk of large losses unless concentration is clearly prudent.
Compliance with the plan document, so long as its terms match federal law; where the document conflicts with ERISA, the statute controls.

Breach exposes fiduciaries personally. The Department of Labor can require them to restore losses caused by their mismanagement out of their own funds.

How Qualification Changes the Tax Picture

Deferral is the point. Traditional 401(k) contributions come out of your paycheck before federal income tax is calculated, cutting your taxable income for the year. Inside the plan, investments grow without annual tax on gains, dividends, or interest.⁶ You owe ordinary income tax only when you take a distribution.

Employers deduct their contributions as business expenses in the year made, and the plan’s trust is a tax-exempt entity so its earnings aren’t taxed at the trust level either. The whole structure pushes the tax bill into retirement, when many people sit in a lower bracket.

Roth contributions run the opposite way. You pay tax now, and qualified withdrawals in retirement (including gains) come out tax-free.

2026 Contribution and Benefit Limits

Federal law caps how much can flow through a qualified plan each year, and the numbers adjust for inflation.

Defined Contribution Plans

The total that can land in your account for 2026, combining your deferrals, employer contributions, and reallocated forfeitures, is $72,000 or 100% of your compensation, whichever is less.² Inside that cap:

Employee elective deferrals: $24,500 across all your 401(k) and 403(b) plans combined.⁷
Catch-up contributions at age 50 and older: an additional $8,000.⁷
Enhanced catch-up for ages 60 through 63: $11,250, replacing the standard catch-up. This higher amount came from SECURE 2.0.⁷
Compensation ceiling: only the first $360,000 of pay counts when calculating contributions or benefits.²

Defined Benefit Plans

The maximum annual benefit a defined benefit plan can pay in 2026 is $290,000 or 100% of your average compensation during your three highest-paid years, whichever is less.² Starting benefits before Social Security’s normal retirement age reduces the cap actuarially. Exceeding these limits can disqualify the plan.

SECURE 2.0 Rules Hitting in 2026

The SECURE 2.0 Act, signed in late 2022, phased in changes over several years. Three of them matter most for 2026.

Mandatory Automatic Enrollment

Any 401(k) plan established after December 29, 2022, must automatically enroll eligible employees at a deferral rate between 3% and 10%, escalating by 1% each year until it reaches at least 10% but no more than 15%. Employees can opt out. The rule doesn’t apply to businesses less than three years old, employers with fewer than 10 employees, church plans, or government plans.

Roth Catch-Up for Higher Earners

Beginning January 1, 2026, if you’re 50 or older and earned more than $150,000 in wages from your employer in the prior year, your catch-up contributions to that employer’s plan must go in on a Roth basis. You still get to make catch-ups; you just pay tax on them now instead of later. Workers earning $150,000 or less keep the pre-tax option if the plan offers it.

Long-Term Part-Time Eligibility

Part-time employees who work at least 500 hours in each of two consecutive 12-month periods must be allowed to make elective deferrals into the employer’s 401(k). The requirement applies for plan years beginning in 2025 and forward. Employers aren’t required to match or make profit-sharing contributions for these workers, but if they do, vesting service is tracked at 500 hours per year.

Getting Money Out

Qualified plans are built to hold money until retirement, and the withdrawal rules reflect it: penalties for taking money early, mandates for taking it once you’re old enough, and narrow exceptions in between.

Required Minimum Distributions

At age 73 you have to start taking required minimum distributions each year, calculated by dividing your account balance by a life expectancy factor the IRS publishes.⁸ If you’re still working for the sponsoring employer and don’t own more than 5% of the business, you can delay RMDs from that specific plan until you actually retire. Missing an RMD brings a steep excise tax on the amount you should have withdrawn.

The 10% Early Withdrawal Penalty

Money taken before age 59½ generally triggers a 10% additional tax on top of ordinary income tax.⁹ Several situations remove the 10% piece, though income tax still applies:

Separation from service in or after the year you turn 55 (age 50 for public safety employees in governmental plans), letting you draw penalty-free from that employer’s plan.⁹
Total and permanent disability.
Death, for distributions to beneficiaries.
Distributions taken because of an IRS levy on the plan.
Qualified birth or adoption expenses, up to $5,000 per child.⁹

Hardship Withdrawals

Some 401(k) plans allow in-service hardship withdrawals for an immediate and heavy financial need. The IRS safe harbor list covers unreimbursed medical expenses for you, your spouse, or dependents; costs of buying a primary home (not mortgage payments); the next 12 months of postsecondary tuition and room and board; payments needed to prevent eviction or foreclosure on your primary residence; funeral expenses; and certain repair costs for damage to a primary home.¹⁰ Hardship withdrawals are taxed as ordinary income, may face the 10% penalty, and can’t be repaid to the plan.

Loans

If your plan permits loans, you can borrow the lesser of 50% of your vested balance or $50,000. Payments must be at least quarterly with level amortization, and the loan must be repaid within five years unless used to buy a primary home. Leave the job with a loan outstanding and the employer can demand immediate repayment; any unpaid balance is treated as a taxable distribution, though rolling it into an IRA by the tax filing deadline avoids the tax hit.¹¹

Spousal Rights and QDROs

Federal law builds in protections for a married participant’s spouse that override the plan’s standard payment options. Pension plans and many defined contribution plans have to offer a qualified joint and survivor annuity as the default form of benefit, continuing payments to your spouse after your death.¹² Picking a different payment form takes written, notarized spousal consent. Plans must also offer a preretirement survivor annuity if you die before retirement.

In divorce, benefits are divided by a qualified domestic relations order. A QDRO gives a spouse, former spouse, or dependent (the “alternate payee”) a right to a portion of your plan benefits. A valid order names both parties, identifies the plan, states the dollar amount or percentage assigned, and specifies the time period covered. It can’t force the plan to pay more than it otherwise would or provide a benefit type the plan doesn’t offer. A signed property settlement isn’t enough on its own; a court or authorized state agency has to issue the order.¹³

Fixing Mistakes Before They Cost the Plan

Operational errors happen, and the IRS runs the Employee Plans Compliance Resolution System so sponsors can correct them and keep qualified status. Depending on the failure, that means self-correcting without contacting the IRS, filing a Voluntary Correction Program submission with a user fee for IRS sign-off, or negotiating a closing agreement if the error surfaces during an audit.¹⁴¹⁵

Losing qualified status without correcting is costly across the board. The plan’s trust becomes taxable and has to file its own return. Vested employees have to include employer contributions in gross income. The employer loses its deduction. Distributions can’t be rolled into an IRA or another qualified plan.¹⁶ The damage lands on everyone connected to the plan, which is exactly why the correction programs exist.

1
Office of the Law Revision Counsel. 26 USC 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
2
Internal Revenue Service. COLA Increases for Dollar Limitations on Benefits and Contributions
3
Office of the Law Revision Counsel. 26 USC 416 – Special Rules for Top-Heavy Plans
4
Internal Revenue Service. 401(k) Resource Guide Plan Participants Summary Plan Description
5
Office of the Law Revision Counsel. 29 USC 1104 – Fiduciary Duties
6
Internal Revenue Service. 401(k) Plan Overview
7
Internal Revenue Service. Retirement Topics – 401(k) and Profit-Sharing Plan Contribution Limits
8
Internal Revenue Service. Retirement Topics – Required Minimum Distributions (RMDs)
9
Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions
10
Internal Revenue Service. Retirement Topics – Hardship Distributions
11
Internal Revenue Service. Retirement Topics – Plan Loans
12
Office of the Law Revision Counsel. 29 USC 1055 – Requirement of Joint and Survivor Annuity and Preretirement Survivor Annuity
13
U.S. Department of Labor. QDROs – An Overview FAQs
14
Internal Revenue Service. EPCRS Overview
15
Internal Revenue Service. Voluntary Correction Program (VCP) – General Description
16
Internal Revenue Service. Tax Consequences of Plan Disqualification