The best post-tax investment options are Roth IRAs, Roth 401(k) and 403(b) plans, taxable brokerage accounts, 529 education savings plans, municipal bonds, and permanent life insurance cash value. Each one takes money you have already paid income tax on and treats the growth or withdrawals differently, so the right choice depends on your income, when you need the money, and what you are saving for.
Roth IRA
A Roth IRA is the first stop for most people who want tax-free growth. You contribute after-tax dollars, the money grows tax-free, and qualified withdrawals in retirement come out tax-free.1Office of the Law Revision Counsel. 26 USC 408A – Roth IRAs
For 2026, you can contribute up to $7,500 if you are under 50, or $8,600 if you are 50 or older. Single filers get the full amount only if modified adjusted gross income stays below $153,000, with contributions phasing out entirely at $168,000. For married couples filing jointly, the phase-out runs from $242,000 to $252,000.2Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 The limit applies across all your IRAs combined.
Getting Money Out
Your original contributions can come out any time, at any age, with no tax and no penalty, because you already paid tax on them. Earnings are stricter. To withdraw earnings tax-free, the account must have been open for at least five tax years and you must be 59½ or older, disabled, or meet another qualifying exception.3Office of the Law Revision Counsel. 26 US Code 408A – Roth IRAs Pull earnings out before both conditions are met and you owe income tax plus a 10% penalty on that portion. The five-year clock starts January 1 of the tax year you make your first contribution, and it only has to be satisfied once.
The Backdoor Roth for High Earners
Income above the phase-out doesn’t lock you out. You can contribute to a traditional IRA on an after-tax basis (no deduction) and then convert that balance to a Roth IRA. Because you already paid tax on the contribution, the conversion usually creates little or no additional tax. The strategy remains legal as of 2026, though proposals to close it come up periodically.
Watch the pro-rata rule. If you already hold pre-tax money in traditional, SEP, or SIMPLE IRAs, the IRS treats a conversion as coming proportionally from all your non-Roth IRA balances, so most of the converted amount ends up taxable. Backdoor conversions work cleanest when you have no other traditional IRA money on the side.
Roth 401(k) and 403(b)
If your employer offers a Roth option in the workplace plan, you can contribute after-tax dollars through payroll deduction with no income limit at all.4Office of the Law Revision Counsel. 26 US Code 402A – Optional Treatment of Elective Deferrals as Roth Contributions The 2026 employee deferral limit is $24,500. Workers 50 and older can add $8,000 in catch-up contributions for a $32,500 ceiling. Workers turning 60 through 63 by year-end get an enhanced $11,250 catch-up, bringing them to $35,750.2Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Roth Employer Match
Before SECURE 2.0, every employer match landed in a pre-tax account even if you chose Roth deferrals. Plans can now let you take matching and nonelective employer contributions directly on the Roth side, so the whole balance grows tax-free.5Internal Revenue Service. SECURE 2.0 Act Changes Affect How Businesses Complete Forms W-2 Not every plan has added the feature yet, so ask your employer.
Mandatory Roth Catch-Up for High Earners
Starting in 2026, if your prior-year wages subject to Social Security tax exceeded $145,000 (adjusted for inflation), any catch-up contributions you make must go into the Roth portion of the plan.6Federal Register. Catch-Up Contributions Above that threshold, sheltering catch-up dollars pre-tax is no longer an option.
No Lifetime RMDs
Roth 401(k) and 403(b) accounts used to force required minimum distributions during the owner’s life. SECURE 2.0 removed that. Designated Roth accounts in workplace plans are no longer subject to RMDs while the owner is alive.7Internal Revenue Service. Retirement Topics – Required Minimum Distributions Beneficiaries still face distribution rules after the owner dies.
Mega Backdoor Roth
Some 401(k) plans let you make after-tax contributions beyond the normal deferral limit and then convert those dollars to Roth, either inside the plan or by rolling them to a Roth IRA. The total 2026 cap on all contributions to a defined contribution plan (your deferrals, employer contributions, and after-tax contributions combined) is $72,000, higher if you qualify for catch-ups.8Internal Revenue Service. COLA Increases for Dollar Limitations on Benefits and Contributions The room between your deferrals plus match and that $72,000 ceiling is what the mega backdoor fills. Because the contributions were already taxed, only any earnings that accumulate before conversion are taxable, so prompt conversion keeps that number small. The strategy needs two specific plan features: after-tax (non-Roth) contributions and either in-service withdrawals or in-plan Roth conversions. Without both, it isn’t available.
Taxable Brokerage Account
A regular brokerage account is the most flexible post-tax option. No contribution limits, no income restrictions, no age rules, no restrictions on when you access the money or what you invest in. The cost is that you pay tax each year on dividends and on gains you realize when you sell.
Capital Gains Rates
Hold something a year or less and any profit is taxed at your ordinary income rate. Hold longer than a year and the gain qualifies for long-term capital gains rates of 0%, 15%, or 20% depending on your taxable income.9Internal Revenue Service. Topic No. 409, Capital Gains and Losses The spread is big enough that holding periods should factor into every sell decision.
Higher earners owe more. The net investment income tax adds 3.8% on top of capital gains rates for single filers with modified AGI above $200,000 and joint filers above $250,000.10Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax Those thresholds are set by statute and don’t adjust for inflation, so more taxpayers get caught by them every year.
Tax-Loss Harvesting
Brokerage accounts have one advantage that sheltered accounts don’t: losses are usable. Selling at a loss offsets capital gains dollar for dollar, and if your net losses exceed your gains, you can deduct up to $3,000 against ordinary income and carry the rest forward indefinitely.11Office of the Law Revision Counsel. 26 USC 1211 – Limitation on Capital Losses
The wash sale rule limits the tactic. Sell a security at a loss and buy the same or a substantially identical security within 30 days on either side, and the loss is disallowed for the current year (it gets added to the replacement shares’ cost basis). The rule reaches across all your accounts, including IRAs and your spouse’s accounts, and brokerages only track wash sales within a single account, so cross-account compliance is on you.
529 Education Savings Plan
A 529 plan lets you invest after-tax dollars for education, and all the growth is free from federal tax so long as you use the money for qualified expenses.12Office of the Law Revision Counsel. 26 US Code 529 – Qualified Tuition Programs Federal law offers no deduction for contributions, but many states give residents a deduction or credit for contributing to an in-state plan.
Qualified expenses cover college tuition, fees, books, and room and board, K-12 tuition at public, private, or religious schools up to $20,000 per beneficiary per year, and up to $10,000 over the beneficiary’s lifetime for qualified student loan repayment.13Office of the Law Revision Counsel. 26 USC 529 – Qualified Tuition Programs The account owner keeps control and can change the beneficiary to another qualifying family member. Withdrawals for non-qualified purposes trigger ordinary income tax plus a 10% federal penalty on the earnings portion.14U.S. Government Publishing Office. 26 USC 529 – Qualified Tuition Programs
Rolling Unused 529 Money to a Roth IRA
Since 2024, unused 529 funds can be rolled directly into a Roth IRA for the beneficiary. The 529 must have existed at least 15 years, only contributions older than five years qualify, the annual rollover counts against the beneficiary’s Roth IRA contribution limit for the year, the beneficiary needs earned income at least equal to the rollover, and a lifetime cap of $35,000 per beneficiary applies. It’s a way out of the penalty for overfunded accounts, though the annual limit means it takes several years to use.
Municipal Bonds
Municipal bonds are debt issued by state and local governments, and the interest they pay is generally exempt from federal income tax.15Office of the Law Revision Counsel. 26 US Code 103 – Interest on State and Local Bonds Buy bonds from your own state and the interest is often exempt from state and local tax too.
Stated yields on municipal bonds run below comparable corporate bonds, so the comparison worth running is the tax-equivalent yield: what a taxable bond would need to pay to leave you with the same after-tax income. In the top federal bracket, a 3.5% muni delivers roughly what a 5.6% taxable bond would after tax. The higher your marginal rate, the more the exemption is worth.
Two tax wrinkles. Selling a bond for more than you paid produces a taxable capital gain. And certain municipal bonds called private activity bonds can trigger the alternative minimum tax, so check the type before buying.
Permanent Life Insurance Cash Value
Whole life and universal life policies pair a death benefit with a tax-advantaged savings feature. Premiums are paid with after-tax dollars, and a portion of each payment builds cash value that grows on a tax-deferred basis inside the policy.16Office of the Law Revision Counsel. 26 US Code 7702 – Life Insurance Contract Defined You owe no annual tax on the internal gains.
The usual way to tap the cash value without triggering tax is a policy loan. A loan isn’t a distribution, so borrowing against the cash value is generally not taxable while the policy stays in force. There is no repayment schedule, and any outstanding balance simply reduces the eventual death benefit.
The scenario to watch is a lapse. If the policy terminates with an outstanding loan, the IRS treats it as a surrender and calculates taxable gain from the full cash value before the loan is repaid, not the cash you actually walk away with. A policy that lapses with $100,000 in cash value, a $60,000 cost basis, and an $80,000 loan produces tax on the $40,000 gain even though you only receive $20,000. Anyone using policy loans should keep close watch on the policy’s health and maintain enough cash value to cover ongoing insurance charges.
These policies also carry higher fees than most investment accounts, and cash value grows slowly in the early years while the insurer recovers costs. Permanent life insurance fits people who have already maxed out Roth IRAs, Roth 401(k)s, and other tax-advantaged accounts, still want additional sheltered growth, and have a real use for the death benefit itself.