The Retirement Account Map: 401(k)s, IRAs, Roths, and NQDC: A Primer

Every retirement account is defined by three tax events: whether money is taxed going in, while it grows, and coming out. Pre-tax accounts (traditional 401(k)s and IRAs) skip tax at contribution, grow tax-deferred, and are taxed as ordinary income at withdrawal. Roth accounts are taxed at contribution and then never again, with tax-free growth and withdrawals. Nonqualified deferred compensation (NQDC) is not an account at all but an employer's contractual promise, taxed when paid and exposed to the employer's credit. Everything else, the alphabet of 401(k), 403(b), 457(b), IRA, SEP, and solo plans, is a container built around one of those treatments, with different limits and rules attached.

This primer is the map: what each account type is, how it is taxed at each stage, the rules that connect them (required minimum distributions and rollovers), and where each fits. It assumes no background. For depth on any single territory, the linked articles go further.

The three tax treatments underneath every account

Pre-tax (traditional).Contributions reduce taxable income today. Growth is untaxed along the way. Withdrawals are ordinary income, generally penalized 10% before age 59 1/2 with exceptions, and eventually forced out by required minimum distributions. The bet: your tax rate in retirement will be lower than your rate today.

Roth.Contributions are made with after-tax dollars. Growth and qualified withdrawals are tax-free, and Roth IRAs have no lifetime distribution requirement, which also makes them efficient assets to leave heirs. The bet runs the other way: pay tax now at a known rate rather than later at an unknown one.

Nonqualified deferral.You and your employer agree, in advance, that part of your compensation will be paid in a future year. No account is funded in your name; you are an unsecured creditor of the company until paid, and the payment is ordinary income when it arrives. The trade is powerful deferral capacity in exchange for credit risk and rigid, irrevocable elections.

Most well-built retirement pictures use more than one treatment. Holding pre-tax, Roth, and taxable assets simultaneously, often called tax diversification, is what later makes tax-smart withdrawal sequencing possible.

Workplace plans: 401(k), 403(b), and 457(b)

The 401(k) is the workhorse: an employer-sponsored plan funded by payroll deferrals, often with an employer match, with both pre-tax and Roth contribution options in most modern plans. For 2026, the employee deferral limit is $24,500, with an $8,000 catch-up at age 50 and an enhanced $11,250 catch-up at ages 60 through 63 (IRS, 2026 limits). Beginning in 2026, employees whose prior-year wages from that employer exceeded $150,000 must make any catch-up contributions as Roth; our 2026 contribution limits article covers the mechanics.

Employer contributions stack on top of employee deferrals, up to a combined defined-contribution ceiling of $72,000 for 2026 under IRS Notice 2025-67 (before catch-ups). Matches may vest over several years; deferrals are always yours immediately.

The 403(b) is the close cousin for schools, hospitals, and nonprofits, with substantially similar limits. The 457(b), for state and local government and some nonprofit employees, has a distinctive feature: its limit is separate from the 401(k)/403(b) limit, so an eligible employee with both plan types can defer into each. Governmental 457(b)s also have no 10% early-withdrawal penalty after separation from service, a meaningful difference for early retirees.

IRAs: traditional, Roth, and rollover

An individual retirement account is personally owned, independent of any employer. The 2026 contribution limit is $7,500, plus a $1,100 catch-up at age 50 (IRS, 2026 limits), and you must have earned income to contribute.

Traditional IRA.Contributions may be tax-deductible, but the deduction phases out at modest income levels if you or your spouse is covered by a workplace plan, which makes the deductible traditional IRA largely irrelevant for high earners as a contribution vehicle. Its main role at higher wealth levels is as a rollover destination for old workplace plans.

Roth IRA.Direct contributions phase out at $153,000 to $168,000 of income for single filers and $242,000 to $252,000 for joint filers in 2026 (IRS). High earners above the limits often contribute through the two-step backdoor route, a nondeductible traditional IRA contribution followed by conversion; the mechanics and the pro-rata trap are covered in our Roth conversions article. The Roth IRA's combination of tax-free growth, no lifetime distribution requirement, and tax-free treatment for heirs makes it the account most worth filling early.

Rollover IRA.Functionally a traditional IRA holding assets moved from former employers' plans. Consolidation simplifies oversight and widens investment choice, though workplace plans can offer stronger creditor protection in some states and unique options worth checking before moving money.

Accounts for business owners and the self-employed

Self-employment income opens larger doors. A SEP IRA allows employer-only contributions of up to 25% of compensation, capped at the $72,000 overall limit for 2026. A solo 401(k) covers an owner (and spouse) with no other employees and combines the $24,500 employee deferral with employer profit-sharing contributions up to the same $72,000 ceiling, usually reaching the maximum at lower income than a SEP; many also permit Roth deferrals. Owners with substantial, stable income who want to put away far more can layer a cash balance pension plan on top, a topic for a separate conversation with actuarial help.

One adjacent container deserves a sentence: the health savings account, available with a high-deductible health plan, is triple tax-advantaged (deductible going in, tax-free growth, tax-free out for medical costs) and functions as a stealth retirement account when invested and left to compound.

NQDC: the unfunded promise

For executives whose savings capacity exceeds every qualified-plan limit, nonqualified deferred compensation plans allow deferral of salary and bonus with no statutory dollar cap. The defining trade-offs: elections are made before the income is earned and are largely irrevocable under Section 409A; distribution schedules are fixed in advance; and deferred amounts remain employer assets, so a bankruptcy can erase them. NQDC rewards confidence in the employer and careful scheduling of distributions into lower-income years. Our deferred compensation article covers election strategy, distribution design, and the state tax angles in depth; the point for the map is that NQDC is a complement to qualified plans, never a substitute for them.

Tax treatment at each stage: the map in one table

What are required minimum distributions?

Pre-tax money is taxed eventually by force. Required minimum distributions (RMDs) compel annual withdrawals from traditional accounts starting at age 73 for those born 1951 through 1959, and age 75 for those born in 1960 or later, under the SECURE 2.0 Act (IRS). The amount is the prior year-end balance divided by an IRS life-expectancy factor, and the penalty for missing one is steep.

Roth IRAs have no lifetime RMDs, and since 2024 Roth 401(k) balances are also exempt. Inherited accounts follow their own regime: most non-spouse heirs must empty the account within 10 years under the SECURE Act, a compressed schedule with real bracket consequences that our inherited IRA article covers. The years between retirement and RMD age are often the best window for Roth conversions, deliberately moving pre-tax money to Roth at low rates; that strategy lives in our Roth conversions article.

Rollover basics: moving money without breaking it

Money moves between containers under specific rules. The safe method is always the direct, trustee-to-trustee transfer, where funds move between institutions without touching your hands. The indirect alternative, receiving a check and redepositing it within 60 days, carries two traps: workplace plans must withhold 20% for taxes (which you must replace from other funds to complete the rollover), and IRA-to-IRA indirect rollovers are limited to one in any 12-month period across all your IRAs.

Three other basics complete the picture. Roth money moves only to Roth containers; pre-tax money can move to pre-tax containers or be converted to Roth as a taxable event. NQDC can never be rolled anywhere; it is paid on its schedule and taxed. And anyone holding highly appreciated employer stock inside a 401(k) should pause before any rollover, because a special net unrealized appreciation election can convert part of the gain to capital-gains treatment, an irreversible choice best made with advice.

Where does each account fit? A hypothetical sequence

Consider a hypothetical 52-year-old executive earning $900,000. Her sequence for the year: defer $24,500 into the 401(k) plus the $8,000 catch-up, which must be Roth given her wages; capture the full employer match; fund the HSA; make a $7,500 backdoor Roth contribution; then defer $150,000 of bonus into the NQDC plan, scheduled to pay out across her first five retirement years when she expects lower brackets; remaining savings go to her taxable account, which has no limits, full liquidity, and capital-gains treatment. The ordering logic is general even though the numbers are not: free money first (match), then the most tax-protected space (HSA, Roth), then unlimited but riskier or less flexible deferral (NQDC), with taxable investing as the flexible foundation throughout. This example is hypothetical and for illustration only.

Key numbers for 2026

Source: IRS 2026 cost-of-living adjustments, including Notice 2025-67.

Where to go deeper

This primer is deliberately a map rather than a guidebook. For the full 2026 limits and the new Roth catch-up mechanics, see our 2026 contribution limits article. For when moving pre-tax money to Roth makes sense and when it does not, see Roth conversions for high earners. For the retirement-phase question of which accounts to draw first, see tax-smart withdrawal sequencing. And for the executive-specific territory of deferral elections and distribution design, see our deferred compensation article.

Frequently asked questions

What is the difference between a 401(k) and an IRA?A 401(k) is employer-sponsored with high limits ($24,500 employee deferral in 2026) and often a match; an IRA is personally owned with lower limits ($7,500) and wider investment choice. Most people use both across a career.

Should I contribute pre-tax or Roth?It depends on your tax rate now versus your expected rate in retirement, which is rarely knowable with confidence. Holding both types hedges the uncertainty and creates flexibility for withdrawal planning later.

Can high earners use a Roth IRA?Not directly above the 2026 phase-outs, but the backdoor contribution route remains available, and Roth 401(k) contributions have no income limit at all.

At what age do RMDs start?Age 73 for those born 1951 through 1959, and age 75 for those born in 1960 or later. Roth IRAs and, since 2024, Roth 401(k)s have no lifetime RMDs.

Is deferred compensation safe?It is a contractual promise, not a funded account; in an employer bankruptcy, deferred amounts can be lost. That credit risk is the price of unlimited deferral capacity and should shape how much you commit.

What happens to these accounts when I die?They pass by beneficiary designation, outside your will, and most non-spouse heirs must empty inherited IRAs within 10 years. Beneficiary forms deserve the same review discipline as estate documents.