Tax-Free Growth

Tax-free growth describes what happens to investment earnings inside an account whose income is never taxed to the owner, so that interest, dividends and realized gains compound without any annual tax and without a tax bill when the money is eventually withdrawn. Roth accounts, health savings accounts used for medical expenses, 529 plans used for education expenses and Coverdell education savings accounts all work this way. The phrase is often used interchangeably with tax deferral, which is a different mechanism: deferred earnings are taxed later rather than never. What makes the distinction real is that tax-free treatment requires a condition to be satisfied at the moment of withdrawal, so the correct description of the benefit while the money is still inside the account is conditional rather than settled.

The two steps, because one alone would not be enough. Exempting the account from tax stops the annual bill on dividends and realized gains, but on its own it would leave the whole balance taxable when it came out, which is how a traditional retirement account works. Tax-free growth needs a second provision excluding the distribution from income. Both halves are written out separately in the Code, and reading them side by side is the clearest way to see the design.

Internal Revenue Code section 408(e)(1) supplies the first half for an individual retirement arrangement: "Any individual retirement account is exempt from taxation under this subtitle." Section 529(a) does the same for a qualified tuition program: "A qualified tuition program shall be exempt from taxation under this subtitle." Section 408A(d)(1) supplies the second half for a Roth: "Any qualified distribution from a Roth IRA shall not be includible in gross income." Section 223(f)(1) supplies it for a health savings account: any amount distributed "which is used exclusively to pay qualified medical expenses of any account beneficiary shall not be includible in gross income."

The second step is a condition, which is why the benefit can be lost. A Roth distribution has to be qualified, which brings in an age or other triggering event and a five-year clock. A health savings account distribution has to be used for qualified medical expenses. A 529 distribution has to be used for qualified education expenses. Fail the condition and the earnings become taxable, usually with an additional tax on top. Note carefully what gets taxed in that case: the contributions were already after-tax money and come back untouched, so the entire consequence lands on the growth, which is precisely the thing the phrase promises. Tax-free growth is therefore best read as a description of an outcome that is available rather than one that has already happened.

The exception inside the exemption: unrelated business income. Section 408(e)(1) does not stop at exempting the account. Its next sentence reads: "Notwithstanding the preceding sentence, any such account is subject to the taxes imposed by section 511." Section 529(a) carries the identical carve-out. Section 511 taxes unrelated business taxable income, and two routes reach an ordinary investor. Section 512(c)(1) pulls in the account's share of a partnership's unrelated business income, which is what happens when an individual retirement account holds a publicly traded partnership. Section 512(b)(4) pulls in income from debt-financed property, which is what happens when an account borrows to invest. Section 512(b)(12) allows a specific deduction of $1,000, so small amounts are absorbed, and above that the account itself owes tax at trust rates and files its own return. The account is still tax-free for everything else in it. This is the one place where "tax-free" overstates the statute rather than summarizing it.

Tax-free growth is not tax-exempt income, and the difference is where the exclusion sits. Interest on a municipal bond is excluded from gross income by the character of the income itself, wherever the bond is held, with no account and no conditions to satisfy. Tax-free growth is a property of the wrapper rather than of the investment inside it, which is why holding a municipal bond in a Roth account adds nothing: the interest was already excluded, and the space in the account has been spent on it.

What the exemption does not cover. It is an exemption from income tax, and not from anything else. Contributing more than the annual limit to an individual retirement arrangement, a health savings account, a Coverdell account or an ABLE account draws a 6 percent excise tax each year under section 4973 until the excess is corrected, capped at 6 percent of the account value. The balance remains part of the owner's estate. And state income tax treatment is a separate question in every case, because a state's conformity to the federal rule is set by that state's own law rather than by the Code.

In sequence, for any account that produces tax-free growth:

1. Money goes in with no deduction. These accounts trade the deduction for the exclusion, with the health savings account as the exception that gets both.
2. Earnings accumulate untaxed, because the account is exempt from income tax while the money is inside. No annual statement of dividends or capital gains reaches your return.
3. A distribution is tested against the account's own condition at the moment it comes out.
4. A qualifying distribution is excluded from gross income in full, contributions and earnings alike.
5. A non-qualifying distribution taxes the earnings, and often adds a penalty, while the contributions come back untaxed.

A hypothetical example of the unrelated-business-income exception, since it is the case people are least prepared for. Marcus holds units of a publicly traded partnership inside a traditional individual retirement account. For one year the partnership reports $4,300 of unrelated business taxable income allocated to his account. The specific deduction under section 512(b)(12) covers the first $1,000, so $3,300 is taxable. The tax is computed at trust rates, the account files its own return, and the tax is paid out of account assets, reducing the balance. Every other dollar in the account continued to grow untaxed. Nothing about this is a penalty or an error; it is what section 408(e)(1)'s second sentence says will happen.

Pros

• The earnings are never taxed, so the compounding is not shared with a future tax bill the way deferred growth is.
• No annual reporting of interest, dividends or gains inside the account, which removes both the tax drag and the paperwork.
• Certainty about the after-tax value of the balance, which deferred accounts cannot offer because future rates are unknown.
• Makes the account the natural home for the holdings expected to grow the most, since the growth is where the whole benefit sits.

Cons

• Conditional. The exclusion depends on how the money comes out, and the cost of failing the test falls entirely on the growth.
• Bought with an up-front cost, since these accounts generally give no deduction on the way in.
• Contribution limits are small relative to the amounts most people need to accumulate, so the benefit is rationed.
• The exemption does not reach unrelated business income, so a partnership holding or a borrowing strategy can create a tax bill inside the account.
• State treatment and estate treatment are separate questions the federal exemption does not answer.