Two identical portfolios, different amounts of money.

Why this essay contains no tax brackets

Start with something most articles on this subject will not tell you.

While researching this we found commercial calculator sites publishing confident dollar thresholds for the current tax year. The IRS page those figures are supposed to come from, Topic no. 409, was last reviewed in February 2026 and still publishes its bracket figures for the prior tax year. At least one of those calculator sites labelled its own numbers as projections pending the final Revenue Procedure. They did not agree with each other.

So this essay prints no dollar thresholds. Not one. Everything below runs on the rate structure, which the IRS does confirm and which does not change every January. When you need the actual numbers for your year, get them from the IRS and nowhere else.

The structure, which is all you need

The US taxes investment income in two fundamentally different ways, and the gap between them is the entire opportunity.

Taxed as ordinary income, at your normal graduated rates: interest from bonds, bond funds and savings accounts; non-qualified dividends; most REIT distributions; and short-term capital gains, which the IRS defines as assets held one year or less.

Taxed at preferential rates of 0%, 15% or 20%: long-term capital gains, meaning assets held more than one year, and qualified dividends.

There are exceptions worth knowing. Collectibles are capped at 28%, unrecaptured section 1250 gain from real property at 25%, and higher earners may owe an additional net investment income tax on top of all of it. But the headline structure is the point: the same dollar of return is taxed very differently depending on what produced it.

And there is a second structural fact that matters just as much. Inside a tax-deferred account nothing is taxed as it happens, and everything is taxed as ordinary income when it comes out. The preferential rate does not exist in there. A tax-deferred account converts capital gains into ordinary income.

The arithmetic

The mechanism is simple enough to hold in your head. A bond yielding 5% in a taxable account at a 24% marginal rate loses 120 basis points a year to tax, every year, compounding against you. Put that same bond in a sheltered account and the drag disappears entirely until withdrawal.

Meanwhile a stock fund in a taxable account is barely taxed at all while you hold it. Only the dividends are, at the preferential rate, and the appreciation compounds untouched until you sell. The tax treatment a stock fund gets for free in a taxable account is the treatment a bond fund has to be sheltered to get.

Two details most comparisons get wrong

Basis tracking. When you reinvest a dividend in a taxable account, you already paid tax on it, and it increases your cost basis. It is not taxed again when you sell. Published comparisons routinely miss this, which systematically overstates how bad the taxable account looks. Our model tracks basis properly, which makes the case for asset location smaller and more honest than the version you usually see.

The deferred account is not tax-free. It is tax-deferred. Everything in the sheltered column above is shown after paying ordinary rates on withdrawal, because that is what actually happens. A comparison that shows a pre-tax 401(k) balance against an after-tax brokerage balance is not a comparison.

It compounds, so starting early matters more than getting it perfect

Horizon	Wrong way	Right way	Difference	Share
10 years	$294,706	$304,848	$10,142	3.4%
20 years	$504,933	$537,730	$32,797	6.5%
30 years	$884,672	$961,067	$76,395	8.6%
40 years	$1,582,582	$1,734,787	$152,206	9.6%

At ten years the gap is $10,142, which is real but not dramatic. At forty it is $152,206. This is the same shape as every other compounding argument on this site, and it points the same direction: the decision is worth most to the person who has the longest left to run, which is exactly the person least likely to have thought about it.

What actually drives the size of the prize

Not the portfolio size. The spread between your two tax rates.

Ordinary rate	Long-term rate	Spread	Benefit	Share
12%	0%	12 pts	$107,750	10.4%
22%	15%	7 pts	$60,842	6.7%
24%	15%	9 pts	$76,395	8.6%
32%	15%	17 pts	$136,201	17.2%
37%	20%	17 pts	$131,549	17.9%

Read the bottom rows. A household in a high bracket gets roughly double the benefit of one in the middle, because they have twice the spread to arbitrage. Asset location is worth the most to exactly the people who already have the most, which is worth saying plainly rather than pretending otherwise.

The top row is the interesting exception. A household in a low enough bracket may face a zero percent long-term rate. For them the taxable account is close to tax-free for stocks already, and the ordering still works but for a slightly different reason.

The ordering, in practice

The general principle: put the tax-inefficient things where tax does not reach them.

Into tax-deferred accounts first: bonds and bond funds, REITs, actively managed funds with high turnover that throw off short-term gains, and anything else generating ordinary income year after year. These are the assets that bleed.

Into taxable accounts: broad stock index funds. Low turnover, mostly qualified dividends, gains deferred until you choose to sell. They are the most tax-efficient thing most people own, which means they need shelter the least.

Into Roth accounts, if you have them: your highest expected return holdings. Roth growth is never taxed, so the shelter is worth most where there is most growth to shelter.

Three things that override all of this. Asset allocation comes first, because owning the wrong mix is a far larger error than holding the right mix in the wrong place. Never let the tax tail wag the investment dog. And if your accounts are not large enough to hold whole asset classes separately, this is not worth contorting your portfolio over.

What this cannot tell you

State taxes are ignored entirely. They range from nothing to substantial and they change the arithmetic, sometimes a lot. Municipal bond interest in particular has federal and state treatment this model does not touch.

Your future rate is unknown. Every tax-deferred calculation assumes a withdrawal rate you cannot know decades in advance. If your rate in retirement is much lower than today, deferral is worth more than modelled. If rates rise, less.

Rules change. Everything here rests on a structure Congress can alter. The general principle, shelter what is taxed most heavily, survives most changes. The specific ordering might not.

Moving existing holdings can trigger tax. Selling an appreciated fund in a taxable account to relocate it creates a gain today. Usually the fix is to direct new contributions rather than reshuffle what you already hold.

None of that changes the core point. Of the three things that determine what you keep, market returns are not yours to control, and your savings rate takes real sacrifice. Asset location takes an afternoon, costs nothing, and the money is sitting there whether you pick it up or not.

Sources and further reading

The tax structure described above comes from the IRS directly. The arithmetic is our own and its assumptions are stated in the essay.

• Topic no. 409, Capital gains and losses, Internal Revenue Service. Establishes the holding-period rule that separates short-term from long-term, the 0/15/20 percent preferential structure, the 28 percent cap on collectibles and section 1202 stock, the 25 percent cap on unrecaptured section 1250 gain, and that short-term gains are taxed as ordinary income at graduated rates. Note that when we checked, this page was last reviewed in February 2026 and still carried figures for the prior tax year, which is precisely why we print no thresholds.
• Topic no. 559, Net investment income tax, Internal Revenue Service, for the additional tax that can apply on top of the rates above.
• Publication 550, Investment Income and Expenses, Internal Revenue Service. The long-form treatment, including what makes a dividend qualified.
• For current-year contribution limits, which this essay also deliberately omits: Retirement topics: contributions.