Since its inception in 1978, the 401(k) plan has grown to become the most popular type of employer-sponsored retirement plan in America. Millions of workers depend on the money that they have invested in these plans to provide for them in their retirement years, and many employers see a 401(k) plan as a key benefit of the job. Few other plans can match the relative flexibility of the 401(k).

What Is a 401(k) Plan?

A 401(k) plan is a retirement savings account that allows an employee to divert a portion of his or her salary into a long-term investment account. The employer may match the employee's contribution up to a limit.

Key Takeaways

  • A 401(k) is a "qualified" retirement plan. That means it is eligible for special tax benefits under IRS guidelines.
  • You can invest a portion of your salary, up to an annual limit.
  • Your employer may or may not match some part of your contribution.
  • The money will be invested for your retirement, usually in your choice of a variety of mutual funds.
  • You can't usually withdraw any of the money without a tax penalty until you're 59½.

This is a "qualified" retirement plan, meaning it is eligible for special tax benefits under IRS guidelines. There are two main types of account with different tax benefits for employees:

  • An investment of pre-tax money. The money is deducted from gross salary with every paycheck. The employee will not owe income taxes on that money until it is withdrawn after retirement.
  • An investment of post-tax money. A type of account called a Roth 401(k) or Roth IRA requires the employee to pay income tax immediately on the money paid in. After retirement, the money can be withdrawn with no further taxes on the contributions or investment earnings.

Not all employers offer a Roth option.

The Defined-Benefit Plan

Qualified plans come in two versions. They may be either defined-contribution or defined-benefit, or pension plans. The 401(k) plan is a defined-contribution plan.

That means that the available balance in the account is determined by the contributions made to the plan and the performance of the investments. The employee must make contributions to it. The employer may choose to match some portion of that contribution, or not. After retirement, the account balance is entirely in the hands of the employee.

As of 2019, about half of employers contributed to their plans, with an average of close to 3% of salary. Many match 50 cents on every dollar of the employee's contribution, up to a limit. Some offer a varying contribution from year to year as a profit-sharing method.

The maximum you can defer taxes on in a 401(k) plan is $19,000 for 2019. If you're aged 50 and older you can add a catch-up contribution of $1,000.

But many employers offer no match at all. And that is a key to the growth of the 401(k) plan as an alternative to the defined-benefit plan.

The defined-benefit plan, also known as a pension, is an expensive proposition for a company to undertake. The account balance may be a factor in the benefit levels, but the payments are for life.

401(k) Contribution Limits

The maximum amount of salary that an employee can defer to a 401(k) plan is $19,000 for 2019. Employees aged 50 and older can make additional catch-up contributions of up to $1,000.

The maximum joint contribution by both employer and employee is $56,000 for 2019, or $62,000 for those aged 50 and older.

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 bonds. They usually range from aggressive growth funds to less-risky conservative funds.

Rules for Withdrawing Money

The distribution rules for 401(k) plans differ from those that apply to IRAs. In either case, an early withdrawal of assets from either plan will mean income taxes are due and, with few exceptions, a 10% tax penalty will be levied.

However, while an IRA withdrawal doesn't require an explanation, a triggering event must be satisfied to receive a payout from a 401(k) plan.

The following are the usual triggering events:

  • The employee retires from the job or leaves it for any other reason
  • The employee dies or is disabled
  • The employee reaches age 59½
  • The employee experiences a hardship as defined under the plan
  • The plan is terminated

Post-Retirement Rules

The IRS requires the owner of a 401(k) account to begin what it calls required minimum distributions at age 70½ unless the person is still employed.

This differs from other types of retirement accounts. Even if you're employed you have to take the required minimum distribution from a traditional IRA (but not a Roth IRA).

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

The Rollover Option

Many retirees transfer the balance of their 401(k) plans to a traditional IRA or a Roth IRA. This rollover allows them to escape the limited investment choices that are often present in 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.

Loans From a 401(k) Plan

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 loan must usually be repaid within five years. A longer repayment period is allowed for a primary home purchase.

The interest rate that you pay to yourself will be comparable to the rate charged by lending institutions for similar loans.

Any unpaid balance will be considered a distribution and will be taxed and penalized accordingly.

Limits for High Earners

For most people, the dollar contribution limits on 401(k)s are high enough to allow for adequate levels of income deferral. An employee who earns $750,000 in 2019 can only use the first $280,000 of income when computing the maximum possible contributions.

Employers have the option of providing non-qualified plans such as deferred compensation or executive bonus plans for these employees. (For related reading, see "Your 401(k): What's the Ideal Contribution?")