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Maximum contributions to 403(b), 401(k) and 457(b) plans

“One of my clients participates in a 401(k) plan [her own “solo (k)”], plus a 403(b) plan and a 457(b) plan (through the public school system). Her accountant is telling her that she, potentially, could contribute twice the $18,500 deferral limit for 2018. How can that be so?”

ERISA consultants at the Retirement Learning Center Resource Desk regularly receive calls from financial advisors on a broad array of technical topics related to IRAs, qualified retirement plans and other types of retirement savings plans, including nonqualified plans. We bring Case of the Week to you to highlight the most relevant topics affecting your business.

A recent call with a financial advisor from Massachusetts is representative of a common inquiry related to the maximum annual limit on employee salary deferrals.

Highlights of Discussion

First off, kudos to your client for working with you and a tax advisor in order to determine what amounts she can contribute to her employer-sponsored retirement plans as this is an important tax question based on her personal situation that is best answered with the help of professionals. Generally speaking, it may be possible for her to contribute more than one would expect given the plan types she has and based on existing plan contribution rules, which are covered in the following paragraphs.

For 2018, 457(b) contributions (consisting of employee salary deferrals and/or employer contributions combined) cannot exceed $18,500, plus catch-up contribution amounts if eligible [Treasury Regulation Section (Treas. Reg. §1.457-5)]. Since 2002, contributions to 457(b) plans no longer reduce the amount of deferrals to other salary deferral plans, such as 401(k) plans. A participant’s 457(b) contributions need only be combined with contributions to other 457(b) plans when applying the annual contribution limit. Therefore, contributions to a 457(b) plan are not aggregated with deferrals an individual makes to other types of plans.

In contrast, the application of the maximum annual deferral limit under Internal Revenue Code Section (IRC §) 402(g) (the “402(g) limit”) for an individual who participates in both a 401(k) and a 403(b) plan requires the individual to aggregate deferrals between the two plans [Treas. Reg. §1.402(g)-1(b)]. Consequently, an individual who participates in both a 457(b) plan and one or more other deferral-type plans, such as a 403(b), 401(k), salary reduction simplified employee pension plan, or savings incentive match plan for employees has two separate annual deferral limits. Let’s look at an example.

Example #1:

For 2018, 32-year-old Erika has an individual 401(k) plan for her business as a self-employed tutor. She is also on the faculty at the local state university, and participates in its 457(b) and 403(b) plans. Assuming adequate levels of compensation, Erika can defer up to $18,500 between her 401(k) plan and her 403(b) plan, plus another $18,500 to her 457(b) plan.

Also, keep in mind the various special catch-up contribution options depending on the type of plan outlined next.

Catch-Up Contribution Options by Plan Type

401(k) 403(b) 457(b)
Age 50 or Over Option


Employees age 50 or over can make catch-up contributions of $6,000 beyond the basic 402(g) limit of $18,500.


15-Years of Service with Qualifying Entity Option:[1]

402(g) limit, plus the lesser of

1) $3,000 or

2) $15,000, reduced by the amount of additional elective deferrals made in prior years because of this rule, or

3) $5,000 times the number of the employee’s years of service for the organization, minus the total elective deferrals made for earlier years.


Age 50 or Over Option


Employees age 50 or over can make catch-up contributions of $6,000 beyond the basic 402(g) limit.


Note: Must apply the 15-year option first

Age 50 or Over Option

Employees age 50 or over can make catch-up contributions of $6,000 beyond the basic 457 deferral limit of $18,500.

Special “Last 3-Year” Option


In the three years before reaching the plan’s normal retirement age employees can contribute either:

•Twice the annual 457(b) limit (in 2018, $18,500 x 2 = $37,000),




•The annual 457(b) limit, plus amounts allowed in prior years not contributed.


Note: If a governmental 457(b) allows both the age-50 catch-up and the 3-year catch-up, one or the other—but not both—can be used.


415 Annual Additions Limit

Another consideration when an individual participates in more than one plan is the annual additions limit under IRC Sec. 415(c),[2] which typically limits plan contributions (employer plus employee contributions for the person) for a limitation year [3] made on behalf of an individual to all plans maintained by the same employer. However, contributions to 457(b) plans are not included in a person’s annual additions (see 1.415(c)-1(a)(2). With respect to 403(b) plans and the 415 annual additions limit, there are special plan aggregation rules that apply.

Generally, the IRS considers 403(b) participants to have exclusive control over their own 403(b) plans [Treas. Reg. Section 1.415(f)-1(f)(1)]. Therefore, in many cases, contributions to a 403(b) plan are not aggregated with contributions to any other defined contribution plan of the individual (meaning two 415 annual additions limits in some cases). An exception to this rule, however, occurs when the participant is deemed to control the employer sponsoring the defined contribution plan in which he or she participates. In such case, a participant must aggregate his or her 403(b) contributions with contributions to any other defined contribution plans that he or she may control [see  IRC § 415(k)(4)].Regarding the treatment of catch-up contributions, the “Age 50 or Over” catch-up contributions [see 1.415(c)-1(b)(2)(ii)(B)] are not included as annual additions, regardless of plan type, whereas the 403(b) “15-Years of Service” catch-up contributions are included as annual additions (IRS 403(b) Fix-It Guide.)

Example #2

Adam is a non-owner, employee of an IRC 501(c)(3) organization that contributes to a 403(b) plan on his behalf. Adam is also a participant in the organization’s defined contribution plan. Because Adam is deemed to control his own 403(b) plan, he is not required to aggregate contributions under the qualified defined contribution plan with those made under the 403(b) plan for purposes of the 415 annual additions test.


Example #3

The facts are the same as in Example #2, except that Adam is also a participant in a defined contribution plan of a corporation in which he is more than a 50 percent owner. The defined contribution plan of Adam’s corporation must be combined with his 403(b) plan for purposes of applying the limit under IRC 415(c) because Adam controls his corporation and is deemed to control his 403(b) plan.

Example #4

Dr. U.R. Well is employed by a nonprofit hospital that provides him with a 403(b) annuity contract. Doctor Well also maintains a private practice as a shareholder owning more than 50% of a professional corporation. Any qualified defined contribution plan of the professional corporation must be aggregated with the IRC 403(b) annuity contract for purposes of applying the 415 annual additions limit.

For more examples, please see the IRS’ Issue Snapshot – 403(b) Plan – Plan Aggregation.


Sometimes individuals who are lucky enough to participate in multiple employer-sponsored retirement plan types are puzzled by what their maximum contribution limits are. This is especially true when a person participates in a 401(k), 403(b) and 457(b) plan. That is why it is important to work with a financial and/or tax professional to help determine the optimal amount based on the participant’s unique situation.

[1] A public school system, hospital, home health service agency, health and welfare service agency, church, or convention or association of churches (or associated organization)

[2] For 2018, the limit is 100% of compensation up to $55,000 (or $61,000 for those > age 50).

[3] Generally, the calendar year, unless the plan specifies otherwise

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