The Rules of a 401(k) Retirement Plan

Mark Cussen, CMFC, has 13+ years of experience as a writer and provides financial education to military service members and the public. Mark is an expert in investing, economics, and market news.

Updated June 09, 2024 Fact checked by Fact checked by Yarilet Perez

Yarilet Perez is an experienced multimedia journalist and fact-checker with a Master of Science in Journalism. She has worked in multiple cities covering breaking news, politics, education, and more. Her expertise is in personal finance and investing, and real estate.

Part of the Series 401(k) Plans: The Complete Guide
  1. 401(k): What It Is, How It Works, Pros, and Cons
  2. Beginner's Guide to 401(k) Types
  3. The Rules of a 401(k) Retirement Plan
CURRENT ARTICLE
  1. How Much Should I Contribute to My 401(k)?
  2. 401(k) Contribution Limits
  3. How 401(k) Matching Works
  4. What Is a Good 401(k) Match? How It Works and What's the Average
  5. Vesting: What It Is and How It Works
  6. My Employer Doesn't Offer a 401(k). Should I Care?

When Changing Jobs

  1. When You Leave Your Job
  2. Why Might Your 401(k) Be Unavailable After You Leave a Job
  3. How to Transfer a 401(k) to a New Employer

Tips and Tricks

  1. 401(k) or IRA: Get Both
  2. Top 7 Reasons to Roll Over Your 401(k) to an IRA
  3. Are Contributions Tax Deductible?
  4. Can My 401(k) be Garnished or Seized?
  5. What Your 401(k) Could Look Like in the Next 20 Years

Since its inception in 1978, the 401(k) plan has become the most popular type of employer-sponsored retirement plan in America. Millions of workers depend on the money they invest in these plans to provide for them in their retirement years and, for many, it's a key benefit of the job.

Few other plans can match the relative flexibility of the 401(k). Sure, there are rules to follow, but that's because you're getting tax breaks from the federal government in return for investing for retirement.

Key Takeaways

What Is a 401(k) Plan?

A 401(k) plan is a retirement savings account that allows an employee to divert a portion of each paycheck salary into long-term investments. The employer may match part of the employee's contribution as a job benefit.

A 401(k) is technically a qualified retirement plan, meaning it is eligible for special tax treatment under Internal Revenue Service (IRS) guidelines.

Defined Contribution Vs. Defined Benefit

Qualified retirement plans come in two versions. They may be either defined contribution plans or defined benefit plans, such as a pension.

The 401(k) plan is a defined contribution plan. That means the employee manages the fund and chooses the investments. When the employee retires, the account balance is theirs to use as they see fit.

(A defined benefit plan, such as a pension, is managed by the employer and guarantees a lifetime payment based on the person's salary history.)

In a traditional 401(k) plan, the money that the employee pays into the 401(k) is tax-deferred. No income taxes will be due until the money is withdrawn. The earnings are not taxed until they're used either.

The Roth 401(k) Variation

Not all employers offer it, but the Roth 401(k) is an increasingly popular variation of the traditional 401(k) plan.

If you have a Roth plan, you'll pay income taxes on the money you pay into your fund. When you withdraw it after you retire, no further taxes will be due on the principal or the earnings.

Employer contributions can only go into a traditional 401(k) account—not a Roth.

401(k) Contribution Limits

The maximum amount of salary that an employee can defer to a 401(k) plan, whether traditional or Roth, is $23,000 for 2024. Employees aged 50 and older can make additional catch-up contributions of up to $7,500.

The IRS also limits the maximum joint contribution by both employer and employee. In 2024, the maximum joint contribution by both parties is $66,000, or $73,500 for those over 50.

Contributions to a traditional 401(k) are made with pre-tax dollars and reduce the employee's taxable income as well as adjusted gross income (AGI). Taxes are deferred until the funds are withdrawn.

The maximum joint contribution between employee and employer cannot exceed the employee's total annual compensation.

Limits for High Earners

For most people, the contribution limits on 401(k)s are high enough to allow for adequate levels of income deferral. But there is a cap.

In 2024, highly paid employees can only use the first $345,000 of income when computing their maximum potential contributions.

401(k) Investment Options

A company that offers a 401(k) plan typically offers employees a choice of several investment options. The options are usually managed by a financial services advisory group such as The Vanguard Group or Fidelity Investments.

The employee can choose one or several funds to invest in. Most of the options are mutual funds, and they may include index funds, large-cap and small-cap funds, foreign funds, real estate funds, and bond funds.

They usually range from aggressive growth funds to conservative income funds. You can adjust your investing strategy from time to time, moving your money to more aggressive or more conservative choices.

Rules for Withdrawing Money

The distribution rules for 401(k) plans differ from those that apply to individual retirement accounts(IRAs), which are not company-sponsored but are available from banks and investment companies.

In either case, an early withdrawal of assets will mean income taxes are due. With few exceptions, a 10% additional tax penalty will be levied on those younger than 59½.

Triggering Events

But while an IRA withdrawal doesn't require a rationale, a triggering event must be satisfied to receive a payout from a 401(k) plan. The following are the usual triggering events:

Money withdrawn from a 401(k) is usually taxed as ordinary income.

Depending on your company's rules, you may also be able to take a loan from your 401(k), paying yourself back over time.

Post-Retirement Rules

Account owners who turned 73 on or after Jan. 1, 2023, must begin taking required minimum distributions (RMDs) at age 73 unless they still work for the sponsoring employer and have a plan that allows them to defer RMDs.

The age for RMDs has been raised a couple of times in the past, and may well be raised again.

The rules for RMDs differ among retirement accounts. Even if you're still employed, you have to take the RMD from a traditional, SEP, or SIMPLE IRA, for example.

The Rollover Option

Retirees may choose to transfer the balance of their 401(k) plans to a traditional IRA or a Roth IRA. This rollover gets them access to a broader array of investment choices than employers usually offer for 401(k) accounts.

If you decide to do a rollover, make sure you do it right. In a direct rollover, the money goes straight from the old account to the new account and there are no tax implications. In an indirect rollover, the money is sent to you first, and you will owe the full income taxes on the balance in that tax year.

If your 401(k) plan has employer stock in it, you are eligible to take advantage of the net unrealized appreciation (NUA) rule and receive capital gains treatment on the earnings. That will lower your tax bill significantly.

To avoid penalties and taxes, a rollover must take place within 60 days of withdrawing funds from the original account. Your wisest choice is to get your money sent directly from your former account administrator to the new account administrator.

401(k) Plan Loans

If your employer permits it, you may be able to take a loan from your 401(k) plan. If this option is allowed, up to 50% of the vested balance can be borrowed up to a limit of $50,000. The borrower must repay the loan within five years. A longer repayment period is allowed for a primary home purchase.

In most cases, the interest paid will be less than the interest on a bank or consumer loan—and you will be paying it to yourself. But be aware that any unpaid balance will be considered a distribution and taxed and penalized accordingly.

In addition, should you leave your employer, you will be required to pay any pending 401(k) loan balance in full or face IRS tax or penalties.

Hardship Distributions

Emergencies happen. And you may find that the only place you can turn to meet your immediate financial needs is your retirement plan. While it may not necessarily be the best route, you have the option to take a hardship distribution or withdrawal.

Several considerations come into play with this kind of withdrawal:

This type of withdrawal is taxable. Full details on hardship distributions are available through the IRS website.

401(k) Strategies

No single retirement strategy is best for everyone. Still, there are tips that benefit most investors, especially those looking to make the most of their retirement savings.

Maximize Employer Match

One of the golden rules of retirement savings is to contribute at least enough money to take full advantage of your employer match.

For example, if your employer matches dollar for dollar your first 4% of 401(k) contributions, you should strive to put at least 4% into your 401(k).

This strategy maximizes the free money you receive from your employer.

Be Mindful of Contribution Limits

The IRS does not permit contributions that exceed its annual 401(k) limits. Should you overcontribute, you are required to then withdraw those excess contributions, triggering taxes and penalties.

In 2024, the 401(k) contribution limit for both traditional and Roth 401(k)s is $23,000. There is an additional catch-up contribution of $7,500 for individuals 50 years or older.

Compare Roth and Traditional 401(k) Benefits

In general, it is better to contribute to a Roth account if your tax bracket is currently low and you expect to be higher in the future. It is usually better to contribute to a traditional account when your tax bracket is currently high.

This is a personal financial decision. A Roth account is a little more pain upfront for a lot of gain down the road. That is, you get no immediate tax break and no reduction in your annual taxable income. But when you withdraw the money after retiring, you'll owe no taxes on that income.

Avoid Early Withdrawals

Should you withdraw retirement plan funds early, in most cases, you will be subject to federal income tax on the withdrawal plus pay a 10% penalty.

The withdrawal also will damage the compounding effect your investments experience over time. Leaving your 401(k) plan as-is for longer maximizes your potential for long-term portfolio growth.

How Do I Start a 401(k)?

If you work for an employer who has a 401(k) plan, you should get information on the plan and how to sign up for it as soon as you start the job. Your pay stub will reflect your contribution as soon as you're enrolled.

A 401(k) plan can only offered through an employer. If you're self-employed or a freelancer, consider opening an IRA for your retirement savings. Many are available through banks and investment companies, so you can pick and choose the type of IRA you want.

What Benefits Does a Traditional 401(k) Plan Offer?

Making your contributions through payroll deductions is a no-fuss, no-muss process.

You're deferring income taxes on that money and lowering your taxable income, year after year. Meanwhile, the money should be piling up nicely until you retire.

If your employer provides a contribution match, it sweetens the pot.

The earlier you start investing, the more your savings compound. Even if you change employers, you can take your account with you.

What's the Difference Between a Traditional 401(k) and a Roth 401(k)?

While traditional 401(k) plans allow you to make pre-tax contributions, the Roth version requires after-tax contributions.

The Roth tax benefit occurs when you make withdrawals from your account. That money is tax-free.

Withdrawals from traditional accounts will be taxed at your income tax rate.

The Bottom Line

Saving for retirement should be on your radar if you hope to maintain the same lifestyle you currently have. But with so many options, where do you start? The best place is the 401(k) plan, which is offered by employers.

If your company has this plan, take advantage of it. This is even more important if your employer matches contributions.

But it isn't just about socking away money. Knowing the ins and outs and the rules associated with the plan can make you a better investor.

Article Sources
  1. Internal Revenue Service. "401(k) Plan Overview."
  2. Internal Revenue Service. "401(k) Limit Increases to $23,000 for 2023, IRA Limit Rises to $7,000."
  3. Internal Revenue Service. "401(k) Resource Guide - Plan Participants - General Distribution Rules."
  4. U.S. Department of Labor. "Types of Retirement Plans."
  5. Internal Revenue Service. "Retirement Plans FAQs on Designated Roth Accounts."
  6. Internal Revenue Services. "2024 Limitations Adjusted."
  7. Internal Revenue Service. "401(k) Plans - Deferrals and Matching When Compensation Exceeds the Annual limit."
  8. Internal Revenue Service. "Publication 590-B (2021), Distributions From Individual Retirement Arrangements (IRAs)."
  9. Internal Revenue Service. "Retirement Topics - Exceptions to Tax on Early Distributions."
  10. Internal Revenue Service. "Hardships, Early Withdrawals and Loans."
  11. Internal Revenue Service. "RMD Comparison Chart (IRAs vs. Defined Contribution Plans)."
  12. Internal Revenue Service. "Rollover Chart."
  13. Internal Revenue Service. "Rollovers of Retirement Plan and IRA Distributions."
  14. Financial Industry Regulatory Authority (FINRA). "401(k) Rollovers."
  15. Internal Revenue Services. "Publication 575 (2021), Pension and Annuity Income."
  16. Internal Revenue Service. "Retirement Topics - Plan Loans."
  17. Internal Revenue Service. "Retirement Topics - Hardship Distributions."
  18. Internal Revenue Services. "Traditional and Roth IRAs."
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Description Part of the Series 401(k) Plans: The Complete Guide
  1. 401(k): What It Is, How It Works, Pros, and Cons
  2. Beginner's Guide to 401(k) Types
  3. The Rules of a 401(k) Retirement Plan
CURRENT ARTICLE
  1. How Much Should I Contribute to My 401(k)?
  2. 401(k) Contribution Limits
  3. How 401(k) Matching Works
  4. What Is a Good 401(k) Match? How It Works and What's the Average
  5. Vesting: What It Is and How It Works
  6. My Employer Doesn't Offer a 401(k). Should I Care?

When Changing Jobs

  1. When You Leave Your Job
  2. Why Might Your 401(k) Be Unavailable After You Leave a Job
  3. How to Transfer a 401(k) to a New Employer

Tips and Tricks

  1. 401(k) or IRA: Get Both
  2. Top 7 Reasons to Roll Over Your 401(k) to an IRA
  3. Are Contributions Tax Deductible?
  4. Can My 401(k) be Garnished or Seized?
  5. What Your 401(k) Could Look Like in the Next 20 Years
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Vesting is a legal term common to employer-provided benefits that means to give or earn a right to a present or future payment, asset, or benefit.

A 401(k) plan is a tax-advantaged retirement account offered by many employers. There are two basic types—traditional and Roth. Here’s how they work.

A Roth 401(k) is an employer-sponsored retirement savings account that is funded with after-tax money. As long as certain conditions are met, withdrawals in retirement are tax-free.

An IRA rollover is a transfer of funds from a retirement account, such as a 401(k), into an IRA. Learn about this type of Roth conversion from a 401(k) and how it is a tax-free strategy

An IRA transfer is the act of moving funds from an individual retirement account (IRA) to a retirement account, brokerage account, or bank account.

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