As an employee, your employer’s 401(k) plan can be your most important wealth building tool. Understanding how it functions will help you build your wealth in a tax efficient manner.

The Plan

A 401(k) plan is established by an employer. The employer provides the account, the account administration, and the investment choices. Usually, the investment options include a menu of stock and bond mutual funds and/or similar investments. In some plans, employer stock is one of the investment choices.

While the employer administers the plan, most of the assets in the plan (see Vesting below) belong the employees in individual accounts. Therefore, the employees, not the employer, enjoy the benefits and burdens of the economic appreciation and/or depreciation of the investments.

Creditor Protection

401(k) plans are subject to a host of rules, most of which (from a practical perspective) are the concern of the employer, not the employee. One important benefit of the rules for employees is that under ERISA, assets in a 401(k) plan are generally protected from creditors. During your lifetime only two creditors can access assets in your 401(k): the IRS and an ex-spouse.

Vesting

Contributions to a 401(k) made by the employee (referred to as “employee deferrals” and “after-tax contributions” — see numbers 1 and 3 below) are always immediately “100% vested.” This means that regardless of whether the employee leaves the employment of the employer tomorrow, he or she owns the money he or she contributed to the 401(k) and any related growth.

However, contributions to a 401(k) account made by the employer may be subject to a vesting schedule. Simply put, vesting means amounts become the property of the employee after the employee has been employed by the employer for a certain period of time.

Some plans use a gradual vesting schedule. The least generous of these is as follows:

Years of Service	Vesting Percentage
2	20%
3	40%
4	60%
5	80%
6	100%

More generous (i.e., quicker) vesting is permissible.

Some plans use a “cliff” vesting schedule. This means that employer contributions go from 0% vested to 100% vested when the employee has been employed for a certain period. The longest permissible period is 3 years.

The growth associated with employer contributions is also subject to vesting.

Vesting incentivizes staying with the same employer for a sufficient period of time to capture all of the employer contributions to a 401(k) plan. It can also incentivize returning to a former employer if you have worked a number of vested years of service for them.

Some plans provide for 100% immediate vesting for employer contributions as well as employee contributions.

Contributions

There are five types of contributions to 401(k) plans, listed below in order of their prevalence (employee deferrals being the most prevalent).

1. Employee Deferrals

Employees can contribute, through payroll withholding, a portion of their salary to a 401(k) plan. All 401(k) plans offer “traditional” contributions, meaning employees can contribute amounts to the 401(k) plan and exclude those amounts from their taxable income for the year. Some plans, but certainly not all plans, also offer “Roth” contributions, which are not excludible from taxable income, but, if properly withdrawn, can be tax free in the future when withdrawn.

Employee deferrals are the only type of contribution to a 401(k) plan that can be done as a “Roth” contribution. All other contributions are “traditional” contributions.

Read here for more on the desirability of Roth contributions compared to traditional contributions.

Neither traditional nor Roth contributions reduce the amount of income subject to payroll (i.e., Social Security and Medicare) taxes.

2. Matching Contributions

Matching contributions are one of the most powerful ways employees can build wealth. Previously, I have written that if you participate in a 401(k) plan with an employer match, you must make it your top wealth building priority to contribute at least enough to your 401(k) to secure all of the employer match.

How does it work? Different employers have varying matching programs. There are two components: 1) the percentage of salary that is matched, and 2) the percentage of the match.

Here is an illustrative example:

Example 1: Elaine Benes works for Pendant Publishing. She is under 50 years old and earns $100,000 in annual W-2 wages. Pendant Publishing matches 100 percent of employee contributions up to 3 percent of salary, and matches 50 percent of employee contributions for the next 2 percent of salary. Based on this matching program, Elaine would be a fool not contribute at least 5 percent of her salary to Pendant Publishing’s 401(k) plan. Doing so will earn her $4,000 of matching contributions from Pendant Publishing on her $5,000 of employee contributions.

Employers vary in terms of when they match contributions. Some employers match employee contributions only once a year (usually at or after year-end). Other employers match employee contributions each pay period. If you work for an employer that does so, you need to be careful not to max-out your 401(k) early in the year, as each pay period requires an employee 401(k) contribution in order to obtain the match. Here is an example:

Example 2: The facts are the same as Example 1. In addition, Pendant Publishing’s matches 401(k) contributions every pay period, and has 24 pay periods per year. Elaine believes it is a good idea to accelerate her 401(k) contributions, and thus contributes $3,750.00 of her salary for each of the first 6 pay periods of the year ($22,500 total) and makes no contributions the rest of the year. For those 6 pay periods she receives an employee match of $166.67 each pay period ($100,000 divided by 24 times 4 percent) for a total annual match of $1,000. By doing this, Elaine misses out on $3,000 of her potential employer 401(k) match, because for the next 18 pay periods, she contributes nothing to her 401(k).

Some 401(k) plans adjust for this and would fully match Elaine’s contribution (in her case, by adding $3,000 to her 401(k) plan), but many do not. In Elaine’s case, she should have stretched out her contribution such that she contributed at least 5 percent of each pay period’s paycheck to her 401(k).

Note that employers are not required to provide a matching program. There are some employer 401(k) plans that provide no match at all.

Tax Treatment: Employer match contributions are traditional contributions. They are not subject to income tax when added to your 401(k), but they will be in the future when withdrawn (as will the growth on matching contributions). Matching contributions are not subject to payroll taxes.

3. After-Tax Contributions

Some 401(k) plans allow for employees to make so-called after-tax contributions to their 401(k) through payroll withholding. These contributions are not excluded from the employee’s taxable income, but do create basis in the 401(k) account. After-tax contributions are what make Mega Backdoor Roth IRA planning possible. Unless one is engaging in Mega Backdoor Roth IRA planning, in most cases after-tax contributions are not advisable.

Tax Treatment: After-tax contributions do not reduce the employee’s taxable income (for both income tax and payroll tax purposes). In the future after-tax contributions are taxable to the employee as withdrawn, but the employee can use the created basis to reduce the income inclusion. Depending on how the 401(k) account is disbursed, that basis recovery may be subject to the Pro-Rata Rule.

4. Profit-Sharing Contributions

Some 401(k) programs have a profit-sharing program, whereby the employer contributes additional amounts to each employee’s 401(k) account based on a formula.

Tax Treatment: Profit-sharing contributions are traditional contributions and are treated in the same manner as matching contributions, including being exempt from payroll tax.

5. Forfeitures

Because of vesting, employees forfeit unvested amounts in their 401(k)s when they leave the employer’s employment prior to fully vesting in the 401(k). When that happens, the unvested amounts must be accounted for. In some plans, the unvested amounts are used to offset plan administrative costs. In other plans, forfeited amounts are added to the remaining participants’ accounts.

Tax Treatment: Forfeitures are traditional contributions and are treated in the same manner as matching contributions, including being exempt from payroll tax.

Contribution Limits

Contribution limits get a bit complicated because there are two distinct 401(k) plan contribution limits, not one. Numerical limits are updated annually by the IRS to account for inflation. The numbers provided below are the numbers for 2023.

Employee Deferrals

There is an annual employee deferral limitation. For 2023, that limit is the lesser of $22,500 or total compensation (if under age 50) and the lesser of $30,000 or total compensation (if 50 or older). The limit applies to Roth employee contributions, traditional employee contributions, or any combination thereof.

This limit is per person, not per employer. Thus, those with side hustlers must coordinate employee deferrals to their large employer 401(k) plan with employee deferrals to their Solo 401(k). I discuss this topic in detail in my book, Solo 401(k): The Solopreneur’s Retirement Account.

All Additions

There is a second, less understood limitation on 401(k) contribution. The annual limit for all additions to 401(k) and other employer retirement accounts is the lesser of $66,000 or total compensation (if under age 50) and the lesser of $73,500 or total compensation (if 50 or older).

The all additions limit applies to the sum of numbers 1 through 5 above (employee deferrals through forfeitures) plus a sixth amount. The sixth amount is the amount which is contributed by your employer to another qualified retirement plan account on your behalf.

Some employers offer additional qualified retirement plans. These plans often provide for a contribution to an account by the employer based on a stated percentage of compensation. Employers use various names for these plans. Contributions may be subject to vesting and are traditional contributions that are not subject to payroll tax.

The all additions limit applies per employer, not per employee as the employee deferrals limit does.

Auto Enrollment

Many employers now auto-enroll new employees in a 401(k) plan. This has two components: contribution level and investment choice. In most cases, new employees should not simply settle for auto-enrollment. When you start a job, you should review your new 401(k) plan and make informed decisions regarding contribution level and investment choice.

Contribution Level

Auto-enrollment will set a contribution level. Not all employers set the contribution level at a level that maximizes employer matching. Even if the automatic contribution level is set at a level that maximizes the employer match, that level might not be the appropriate level for any particular person.

Investment Selection

Plans typically have a default investment plan for new 401(k) participants. It is best to review your investment options when you start a new job and select an appropriate investment allocation for your circumstances.

Withdrawals from Traditional 401(k)s

When a taxpayer is 59 ½ years old or older, they can withdraw amounts in a traditional 401(k) penalty free. Withdrawals are included in taxable income as ordinary income. Beginning at age 72, taxpayers must take out a required minimum distribution (“RMD”) for each year. The RMD is computed based on IRS tables.

If a taxpayer withdraws money from a 401(k) prior to age 59 ½, the withdrawal is not only taxable, it is subject to a 10 percent early withdrawal penalty, unless a penalty exception applies.

Taxpayers may transfer amounts in a 401(k) to another 401(k) to an IRA. Amounts in traditional 401(k)s and IRAs can be converted to Roth accounts. Such conversions create taxable income, but are not subject to the early withdrawal penalty.

Conclusion

Your workplace 401(k) plan is a vitally important wealth building tool. It is important to be an informed user of your 401(k) in order to build tax advantaged wealth.

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This post is for entertainment and educational purposes only. It does not constitute accounting, financial, investment, legal, or tax advice. Please consult with your advisor(s) regarding your personal accounting, financial, investment, legal, and tax matters. Please also refer to the Disclaimer & Warning section found here.