1. Introduction – What is Publication 4674?
IRS Publication 4674, titled Automatic Enrollment 401(k) Plans for Small Businesses, is an official informational guide jointly issued by the Internal Revenue Service (IRS) and the U.S. Department of Labor Employee Benefits Security Administration (EBSA). This publication explains how employers can set up and operate a 401(k) plan that automatically enrolls employees rather than waiting for them to sign up manually.
According to the official IRS forms and publications repository for 2026, the core standing version of Publication 4674 is Catalog Number 51461H (Revision Date November 2020, posted March 4, 2021). As of late 2026, this guide remains the primary foundational framework referenced by the IRS, operating in tandem with landmark SECURE 2.0 Act mandates and recent IRS Employee Plans guidance, such as Revenue Procedure 2026-34 issued in October 2026. Together, these rules outline mandatory auto-enrollment standards, safe harbors, and penalty protections for modern retirement plans.
2. Who Should Read This Publication
Publication 4674 is written primarily for small business owners, human resources managers, and payroll coordinators who want to provide a workplace retirement plan. It helps employers understand their legal duties and evaluate whether automatic enrollment fits their workforce goals.
Employees who work for companies with automatic enrollment features will also benefit from reading this guide. It clarifies employee rights, default payroll deduction percentages, and how to opt out or change contribution amounts. Additionally, bookkeepers, tax professionals, and financial advisors consult this publication when helping small businesses maintain compliant retirement systems.
3. Key Topics Covered
The publication covers all aspects of designing, implementing, and running an automatic contribution retirement plan. Major topics include:
- The three primary automatic enrollment plan structures permitted by the IRS.
- Rules for setting default contribution percentages and annual automatic increases.
- Required annual participant notice requirements and strict timing windows.
- Fiduciary rules for selecting qualified default investment alternatives (QDIAs).
- The 90-day permissive withdrawal rule allowing employees to reverse automatic enrollment.
- Tax credits available to offset the cost of starting and maintaining automatic plans.
4. Detailed Breakdown of Main Concepts
Automatic enrollment simplifies retirement saving by turning participation into the default choice. If an eligible worker takes no action, the employer automatically deducts a set percentage of their wages and deposits it into a retirement account.
The Three Automatic Contribution Arrangements
Publication 4674 details three specific types of automatic arrangements recognized under federal tax law:
| Arrangement Type | Employer Contribution Required? | Special Testing Relief? | Withdrawal Window |
|---|---|---|---|
| Basic Automatic Contribution Arrangement (Basic ACA) | No, voluntary matching or nonelective contributions only. | No, must undergo standard annual nondiscrimination testing (ADP/ACP tests). | No permissive 90-day withdrawal option unless specifically added. |
| Eligible Automatic Contribution Arrangement (EACA) | No, employer matching remains optional. | Gives employers an extended 6-month window to correct failed nondiscrimination tests without penalty. | Allows employees to opt out and withdraw funds within 30 to 90 days of first deduction. |
| Qualified Automatic Contribution Arrangement (QACA) | Yes, mandatory employer matching or a 3% nonelective contribution is required. | Exempts the plan entirely from annual ADP/ACP nondiscrimination testing (Safe Harbor status). | Permissive withdrawal feature is optional; requires 100% vesting after 2 years of service. |
Default Investments (QDIAs)
When an employee is enrolled automatically, the employer must decide where to put the money if the worker does not select an investment fund. Publication 4674 highlights the Department of Labor rules regarding Qualified Default Investment Alternatives (QDIAs). Employers who pick suitable life-cycle funds, target-date retirement funds, or balanced portfolios gain protection from legal liability for market fluctuations.
Participant Notice Requirements
Employers cannot simply take money from paychecks without warning. Plan administrators must send written notice to eligible employees at least 30 days (and no more than 90 days) before the start of each plan year. For newly hired workers, the notice must be provided before their first payroll deduction occurs. The notice must explain the default contribution rate, how investments are handled, and how to opt out.
5. Practical Examples or Scenarios
Scenario A: The Auto-Enrolled New Hire
Sarah begins working for an engineering firm that uses an Eligible Automatic Contribution Arrangement (EACA) with a 4% default rate. Sarah receives her plan notice on her first day of work. Because she does not submit an opt-out form, 4% of her gross pay is deposited into an age-appropriate target-date fund starting with her second paycheck. Three weeks later, Sarah decides she prefers to direct her savings elsewhere. She exercises her permissive withdrawal option within the 90-day window, receives her deferred wages back with earnings, and avoids any early withdrawal penalty.
Scenario B: The Small Business Seeking Safe Harbor
A manufacturing shop with 25 employees struggles every year with failed ADP nondiscrimination testing because lower-paid workers rarely enroll. The owner converts the plan to a Qualified Automatic Contribution Arrangement (QACA) with automatic 3% matching contributions and a 1% annual automatic escalation feature up to 6%. Because the plan meets QACA safe harbor requirements under Publication 4674, the business owner avoids costly annual testing and benefits from predictable employer contribution budgeting.
6. How This Publication Relates to Specific Forms
Publication 4674 directly intersects with several vital IRS and Department of Labor tax forms:
- Form 5500 (Annual Return/Report of Employee Benefit Plan): Employers use this form each year to report financial conditions, investments, and participant totals of their 401(k) plan.
- Form 8881 (Credit for Small Employer Pension Plan Startup Costs): Eligible small businesses use this form to claim startup tax credits, including additional tax credits for adding auto-enrollment features under the SECURE Act and SECURE 2.0.
- Form 1099-R (Distributions From Pensions, Annuities, Retirement or Profit-Sharing Plans): When an employee requests a 90-day permissive withdrawal from an EACA, the plan custodian reports the distributed amount on Form 1099-R as taxable income without applying an early distribution penalty tax.
- Form 5330 (Return of Excise Taxes Related to Employee Benefit Plans): Used by plan sponsors to pay excise taxes if non-safe harbor nondiscrimination tests fail and corrective refunds are not made in a timely manner.
7. Common Misunderstandings Clarified
Many small employers and employees harbor common misconceptions about automatic enrollment:
- Misconception: Automatic enrollment forces employees into a plan permanently.
Reality: Automatic enrollment only creates an automated starting point. Employees can change their contribution amount to any allowable percentage or opt out entirely at any time. - Misconception: All automatic enrollment plans require expensive company matches.
Reality: Only QACA safe harbor plans require mandatory employer contributions. Basic ACAs and EACAs permit automatic enrollment without requiring any employer matching. - Misconception: Small businesses are legally prohibited from deducting retirement funds without explicit employee signatures.
Reality: Federal law under ERISA and the Internal Revenue Code explicitly preempts state wage-withholding laws, allowing automatic payroll deductions as long as proper advance notice is provided.
8. Why This Publication Matters for Taxpayers
For small business owners, Publication 4674 serves as an operational roadmap to avoid expensive plan defects and tax penalties. Sponsoring a plan with automatic enrollment dramatically boosts company-wide participation, making it easier for owners and key executives to maximize their own tax-deferred contributions.
For everyday workers, understanding this publication ensures they understand how payroll deductions work, how their retirement funds grow over time, and how to adjust their accounts. Auto-enrollment removes procrastination, ensuring that hard-earned retirement dollars start growing as early in a worker’s career as possible.
9. Frequently Asked Questions
What is the minimum default contribution percentage?
Under general ACA and EACA rules, employers can pick any reasonable default rate (often 3% or 4%). However, for safe harbor QACA plans, the default rate must start at a minimum of 3% and gradually increase by 1% each year until it reaches at least 6% (and no more than 10% to 15%).
Can an employee get a refund if they were auto-enrolled by accident?
If the plan contains an EACA provision, an employee has between 30 and 90 days after the date of their first automatic payroll deduction to request a full permissive withdrawal. The employee pays regular income tax on the returned amount, but no early withdrawal penalty applies.
Do small business owners get tax credits for adding automatic enrollment?
Yes. Eligible employers can receive a federal tax credit through Form 8881 just for adding an automatic contribution arrangement to a new or existing retirement plan. This credit is designed to offset setup and administrative expenses during the first three years of adoption.
What happens if an employer fails to send the annual participant notice?
Failing to provide timely notices is a qualification defect. If notices are missed, the employer may lose favorable safe harbor exemptions, face Department of Labor penalties, and be required to complete corrective actions through IRS retirement plan compliance resolution programs.
10. Conclusion
IRS Publication 4674 provides clear instructions for employers who want to simplify retirement savings through automatic 401(k) enrollment. By automating paycheck deductions while preserving each worker’s choice to opt out, small businesses can dramatically increase employee savings rates while securing valuable business tax credits. Whether choosing a basic setup or an advanced safe harbor design, understanding this publication helps business owners remain compliant and empowers workers to build long-term financial security.
