A 401(k) Is a Workplace Plan Built on Payroll Deferrals

A 401(k) is an employer-sponsored defined contribution retirement plan that lets employees put part of each paycheck into an individual investment account. The name comes from section 401(k) of the Internal Revenue Code, which allows those salary deferrals to be made on a pre-tax basis, or as Roth contributions where the plan offers them.

The employee chooses how much to defer and how to invest it from a menu the employer selects, and many employers add a matching contribution. What the account is worth at retirement depends on how much goes in and how the investments perform, so the employee carries the investment risk.

For millions of American workers, the 401(k) is the main retirement account they will ever own, which is why advisers are expected to understand it in detail. For the full route from the exam to a career giving that advice, our complete guide to how to become an investment adviser representative covers every step.

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Traditional and Roth Deferrals

Most plans now offer two ways to contribute. A traditional deferral is taken from pay before income tax, reducing taxable income this year; the money grows tax-deferred, and every dollar withdrawn in retirement, contributions and earnings alike, is taxed as ordinary income.

A Roth deferral is made from pay after income tax, so there is no deduction today. Qualified withdrawals, made after age 59½ and once the Roth account has been open for at least five years, come out completely tax-free, earnings included. The Roth 401(k) has no income limit, unlike the Roth IRA, so high earners can use it freely.

The choice is a bet on tax rates: pay tax now at today’s rate, or later at the rate that applies in retirement. The Series 65 Exam Preparation course at FRC works through these trade-offs, along with the rules for every major retirement account on the exam.

Traditional 401(k), Roth 401(k) and IRA Compared

2026 Contribution Limits

For 2026, an employee can defer up to $24,500 into a 401(k), and that single limit covers traditional and Roth deferrals combined. Employees aged 50 or older can add an $8,000 catch-up contribution, for a total of $32,500, and those aged 60 to 63 can instead add a higher catch-up of $11,250, for a total of $35,750.

A separate ceiling caps everything that goes into the account in a year, including employer contributions: for 2026, total annual additions cannot exceed $72,000, excluding catch-ups, or 100 percent of pay if lower. The amount of salary that can be counted when calculating contributions is capped at $360,000.

From 2026, a SECURE 2.0 rule also changes catch-up contributions for higher earners. Employees whose FICA wages from the employer exceeded $150,000 in the previous year must make any catch-up contributions as Roth contributions, so the tax break moves from today to retirement.

Employer Contributions and Vesting

Employers can add money in two main ways. A matching contribution depends on the employee’s own deferral, such as 50 cents per dollar on the first 6 percent of pay, while a nonelective contribution, such as 3 percent of pay, goes to every eligible employee whether or not they contribute.

Employee deferrals are always 100 percent vested immediately. Employer contributions can follow a vesting schedule that is no slower than a three-year cliff or a six-year graded schedule, so an employee who leaves early may forfeit part of the employer money.

Traditional plans must pass annual nondiscrimination tests to show they do not favour highly compensated employees, defined for 2026 by a $160,000 pay threshold. A safe harbor 401(k), which commits the employer to a set match or nonelective contribution that vests immediately, is exempt from the main tests. Our comparison of defined benefit vs defined contribution plans explains how the 401(k) fits alongside traditional pensions.

Worked Example: What a Deferral Really Costs

An employee earns $80,000 and is in the 22 percent federal tax bracket. The employer matches 50 percent of deferrals up to 6 percent of pay.

Step one: a 6 percent traditional deferral puts $4,800 a year into the account. Step two: the employer match adds 50 percent of that, or $2,400. Step three: because the deferral is pre-tax, federal income tax falls by 22 percent of $4,800, or $1,056.

Step four: the employee’s take-home pay drops by only $3,744, the $4,800 deferral minus the $1,056 tax saving, yet $7,200 goes into the account. Every dollar of reduced take-home pay buys almost two dollars of retirement savings, before any growth through compound interest.

Had the employee deferred only 3 percent, the match would have been $1,200 instead of $2,400. Contributing below the level needed for the full match leaves part of the pay package unclaimed.

Choosing the Investments

The employer, acting as plan fiduciary, selects the investment menu, typically a range of mutual funds covering stocks, bonds and cash, plus target-date funds that shift gradually from stocks to bonds as a chosen retirement year approaches. Employees who are automatically enrolled and never make a choice are placed in a qualified default investment, usually a target-date fund.

Good asset allocation matters more than picking the single best fund. An adviser helping a client with a 401(k) looks at the whole household picture, including other accounts, and uses the plan menu to build a diversified mix that matches the client’s time horizon.

Fees also matter over decades. A difference of half a percentage point in annual costs can reduce a final balance by tens of thousands of dollars over a career, which is why plan fiduciaries must keep costs reasonable.

Study Retirement Plans With FRC

The 401(k) touches tax law, employment law, investment selection and client advice, and the exam tests all four. Our Series 65 course takes you through employer plans, IRAs, rollovers and distributions in a clear sequence, with practice questions at every stage.

Consider studying with FRC for every exam on your route. Explore our USA exam courses, from the SIE through the Series 7, Series 63 and Series 65.

To take advantage of the membership, explore FRC Professional Membership, which gives you a verified Digital Profile that shows employers your real-time course progress, together with the Video Resume. Current offers are on our membership deals page.

Getting Money Out: Withdrawals and Penalties

Withdrawals from a traditional 401(k) are taxed as ordinary income. Withdrawals before age 59½ also generally face a 10 percent additional tax, unless an exception applies.

Important exceptions include separation from service in or after the year the employee turns 55, known as the rule of 55, as well as disability, certain medical expenses and payments to a former spouse under a court order. Plans may also allow hardship withdrawals for an immediate and heavy financial need, such as preventing eviction, but these are still taxable and usually still face the 10 percent penalty.

Pre-tax balances are subject to required minimum distributions from age 73. Roth 401(k) balances are exempt from lifetime required distributions since 2024, and an employee still working for the plan sponsor who does not own more than 5 percent of the company can usually delay distributions from that plan until retirement.

401(k) Loans

Many plans let participants borrow from their own account. The maximum loan is the lesser of $50,000 or 50 percent of the vested balance, although a plan may allow up to $10,000 even where that exceeds half the balance.

Loans must generally be repaid within five years through payroll deduction, with interest paid back into the participant’s own account. A longer term is allowed for a loan used to buy a principal residence.

Worked example: an employee with a vested balance of $70,000 can borrow the lesser of $50,000 and $35,000, so the maximum is $35,000. If the employee leaves the job and does not repay, the outstanding balance is treated as a distribution, but the employee has until the tax filing deadline for that year, including extensions, to roll that amount into an IRA and avoid tax and penalties.

Leaving an Employer: Rollovers

A departing employee has four main choices: leave the money in the old plan if the balance allows it, roll it into the new employer’s plan, roll it into an IRA, or take the cash. Cashing out triggers income tax and, under age 59½ and without an exception, the 10 percent penalty.

A direct rollover moves the money straight from the plan to the new plan or IRA, with no tax withheld. An indirect rollover pays the money to the employee first, and the plan must withhold 20 percent for federal tax.

Worked example: a participant takes a $100,000 indirect distribution and receives $80,000 after the 20 percent withholding. To avoid tax on any of it, the participant must deposit the full $100,000 into an IRA within 60 days, making up the $20,000 from other savings and recovering the withholding when filing taxes. Any amount not rolled over is taxable, which is why the direct rollover is almost always the better route.

ERISA, Fiduciaries and Rollover Advice

Most 401(k) plans are governed by ERISA, the federal law that sets standards for participation, vesting, reporting and fiduciary conduct. The employer and anyone else with discretion over the plan’s investments must act solely in participants’ interests, prudently and with reasonable costs, the core duties of any fiduciary.

Rollover recommendations draw close regulatory attention. Moving money from a low-cost plan into an IRA can raise a client’s costs while generating fees for the adviser, so the recommendation must meet Regulation Best Interest for a broker-dealer or the fiduciary duty for an investment adviser.

A sound rollover recommendation compares fees, investment choice, services, creditor protection and withdrawal rules between the plan and the IRA, and documents why the move serves the client. For a review of the broader conduct standards, see our FINRA rules quick reference on duties and conflicts.

Related Plans: 403(b), 457(b) and Solo 401(k)

A 403(b) plan works much like a 401(k) but is offered by public schools, hospitals and other tax-exempt organisations, and shares the same $24,500 deferral limit. A governmental 457(b) plan serves state and local government workers, and its distributions after leaving the employer are not subject to the 10 percent early withdrawal penalty.

A solo 401(k) is designed for self-employed people with no employees other than a spouse. The owner can contribute both as employee, through deferrals, and as employer, through a profit-sharing contribution, up to the $72,000 annual additions limit for 2026.

The Memory Aid

Remember three numbers and one rule. The numbers are 24,500, 8,000 and 72,000: the 2026 deferral limit, the age-50 catch-up and the total annual additions ceiling.

The rule is “fifty, fifty, five” for loans: the lesser of $50,000 or 50 percent of the vested balance, repaid within five years.

For rollovers, remember “direct is clean, indirect costs twenty”: a direct rollover has no withholding, while an indirect one loses 20 percent at source that must be replaced within 60 days.

Exam Traps to Avoid

The first trap is treating the traditional and Roth 401(k) as having separate deferral limits. The $24,500 limit is shared, so an employee cannot defer $24,500 to each.

The second trap is applying Roth IRA income limits to the Roth 401(k). There is no income limit for Roth deferrals in a workplace plan.

The third trap is assuming the 20 percent withholding applies to a direct rollover. It applies only when the distribution is paid to the participant. The fourth trap is forgetting the rule of 55, which allows penalty-free withdrawals from the plan of the employer the participant left, but not from an IRA.

A Client Scenario

A 56-year-old client earning $140,000 has just left her employer with a $420,000 401(k) balance and an outstanding loan of $15,000. She plans to retire fully within two years and asks whether to roll everything into an IRA.

The adviser points out that because she separated from service after age 55, she can take penalty-free withdrawals from the 401(k) itself, which she would lose for any money moved to an IRA before 59½. The adviser also flags that the unpaid loan will be treated as a distribution unless she rolls over that amount by her tax filing deadline.

The recommendation is to leave enough in the plan to cover her expected withdrawals until 59½, repay or roll over the loan offset, and compare the plan’s fees and fund choices with an IRA before moving the rest. The analysis reflects her goals, time horizon and risk tolerance, the basis of every suitability judgment.

The Dictionary as a Video Library

The FRC dictionary is a study tool, not just a glossary. Every entry pairs a written explanation with deep-dive video, on-page quizzes and interactive flash cards, so you can read a concept, watch it explained and test yourself in one place.

Rules are covered in the same depth: open a rule such as Regulation Best Interest and you will find the full explanation alongside video walk-throughs of how it applies in practice. Use the FRC dictionary to open every term in this article as its own explanation, video and quiz.

Practice Questions to Test Yourself

Question one: A 45-year-old employee wants to defer the maximum to a traditional 401(k) and the maximum to a Roth 401(k) in 2026. What is the most she can defer in total? $24,500, because the deferral limit is shared across traditional and Roth deferrals.

Question two: A participant has a vested balance of $120,000. What is the maximum 401(k) loan? $50,000, the lesser of $50,000 and 50 percent of the vested balance, which is $60,000.

Question three: A participant takes a $50,000 indirect rollover distribution. How much does she receive, and how much must she deposit within 60 days to avoid tax? She receives $40,000 after 20 percent withholding, and must deposit the full $50,000.

Question four: A 61-year-old wants to make the largest possible deferral in 2026. What is the limit? $35,750: the $24,500 deferral limit plus the $11,250 catch-up available at ages 60 to 63.

Question five: An employee leaves his job at age 56 and takes a withdrawal directly from that employer’s 401(k). Does the 10 percent additional tax apply? No, the rule of 55 exempts withdrawals from the plan of an employer the participant left in or after the year he turned 55, although ordinary income tax still applies.

Turn Retirement Plan Knowledge Into Career Evidence

Retirement plan expertise is valued in wealth management, rollover and retirement income advice, and the growing field of workplace plan consulting. FRC’s Digital Profile shows employers the courses you are actively studying and the progress you have earned through assessed learning, verified by FRC, and a QR code on your resume takes them straight to it.

The FRC Video Resume lets a hiring manager hear you before the interview. Explaining clearly whether a client should leave money in a plan or roll it to an IRA is exactly the judgment advisory firms want to see.

Candidates returning to the exam should note that the wait after a third failure drops from 180 days to 60 days for exam windows opened on or after January 4, 2027, as explained in our article on the Series 65 retake rule change.

Related Questions

Continue with Defined Benefit vs Defined Contribution Plans to see where the 401(k) fits, and Traditional IRA vs Roth IRA for the individual accounts most rollovers land in.

For turning a balance into income, read Fixed vs Variable Annuity, and for moving between insurance contracts, What Is a 1035 Exchange?.

Key Points to Retain

A 401(k) is an employer-sponsored defined contribution plan funded mainly by employee payroll deferrals, often with an employer match, in which the employee bears the investment risk. Deferrals can be traditional, taxed on withdrawal, or Roth, tax-free on qualified withdrawal, and share a 2026 limit of $24,500 plus catch-ups of $8,000 at 50 or $11,250 at ages 60 to 63.

Total annual additions are capped at $72,000 for 2026. Withdrawals before 59½ generally face a 10 percent penalty unless an exception such as the rule of 55 applies, loans are capped at the lesser of $50,000 or half the vested balance, and a direct rollover avoids the 20 percent withholding that applies to indirect rollovers.

For the exam’s structure and requirements, see the Series 65 dictionary entry, and for the role the exam leads to, read our guide to what an investment advisor representative is.