Most people have never heard of the step-up in basis rule. That’s a shame, because for anyone who stands to inherit stocks, mutual funds, or a brokerage account from a parent or spouse, it’s one of the most valuable tax provisions in the entire tax code — and it requires exactly zero planning on the part of the heir. You don’t apply for it. You don’t file paperwork to claim it. It happens automatically, by law, when someone dies and passes appreciated assets to their heirs.
Here’s the short version: when you inherit stock or other investment assets, the IRS resets your cost basis to the fair market value on the date of death. Whatever gain had accumulated during the original owner’s lifetime simply disappears from a tax perspective. Permanently. You owe nothing on it — not federal capital gains tax, not state capital gains tax, nothing. I’ve been thinking about probability and risk management my whole career, and I don’t use the word "free" loosely. But on appreciated assets, the step-up in basis is as close to a free tax elimination as exists in American law.
The Dollar Math: What It Actually Saves
Let me run you through a concrete example, because the abstract rule is less motivating than the real numbers.
Your father bought 1,000 shares of a large-cap stock in the mid-1980s at $8 per share. His cost basis: $8,000. By the time he passes, that stock is trading at $95 per share. The holdings are worth $95,000. His embedded, unrealized gain: $87,000.
Without the step-up rule, if he had sold those shares before he died, he’d have owed federal capital gains tax on $87,000. At the 15% long-term rate — applicable to most middle-income earners — that’s $13,050 to the IRS. If he was in the 20% capital gains bracket, it’s $17,400. And depending on the state, there may be additional state capital gains taxes on top of that.
With the step-up rule, you inherit those shares with a new cost basis of $95,000 — the fair market value at his date of death. You sell them the next week. Your taxable gain: $0. Tax owed: $0. The $13,050 to $17,400 that would have gone to the federal government disappears entirely.
Now scale that up to a realistic estate that includes multiple holdings:
- $40,000 in an S&P 500 index fund purchased years ago at a cost basis of $12,000 — gain: $28,000
- $55,000 in individual stocks, cost basis $18,000 — gain: $37,000
- $30,000 in a mutual fund, cost basis $14,000 — gain: $16,000
Total fair market value: $125,000. Total embedded gain: $81,000. Without the step-up, heirs selling those assets would owe roughly $12,150 to $16,200 in federal capital gains taxes. With the step-up, the basis on all three resets to the date-of-death values. Tax owed on any immediate sale: $0. If assets continue to grow after inheritance and are later sold, only the gain above the stepped-up basis is taxable — which means even long-term holders benefit.
What Qualifies and What Doesn’t
This part matters. Not every inherited asset gets a step-up.
Gets a step-up in basis:
- Individual stocks and ETFs held in taxable brokerage accounts
- Mutual funds in taxable accounts
- Real estate (the basis steps up to fair market value at death)
- Bonds held in taxable accounts
Does NOT get a step-up:
- Traditional IRA and 401(k) accounts — these were never taxed on the way in, so there’s no capital gain to step up. Heirs pay ordinary income tax on distributions, which is why the inherited IRA 10-year rule matters so much for timing those withdrawals.
- Roth IRA accounts — gains are already tax-free, so the step-up is irrelevant (and the account passes to heirs with the same favorable tax treatment)
- Annuities — gains are taxed as ordinary income when distributed, regardless of inheritance
- Savings bonds
The distinction between taxable brokerage accounts and tax-deferred retirement accounts is critical for estate planning. A parent with $200,000 in a traditional IRA and $200,000 in a taxable brokerage account is not leaving equal assets to their heirs — the IRA has a substantial future tax liability embedded in it, while the brokerage account (if it holds appreciated assets) may be nearly tax-free for heirs thanks to the step-up.
Community Property States: An Extra Bonus
If you live in one of the nine community property states — Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, or Wisconsin — the step-up works even more favorably for married couples. In these states, when a spouse dies, the entire community property asset steps up to fair market value, not just the deceased spouse’s half. That means a surviving spouse who inherited their partner’s share of stock also gets their own half stepped up at the same time.
So if a married couple in California bought stock for $40,000 that’s now worth $120,000, and one spouse dies, the surviving spouse’s new basis on the entire position is $120,000 — not just $80,000 (their half of the step-up plus the original $20,000 basis on their half). That’s a significant additional benefit that many people in community property states don’t know they’re entitled to.
The Planning Implication: Don’t Sell Appreciated Assets Before You Die
This sounds almost morbid, but it’s one of the most practically important conclusions from understanding this rule: if an elderly parent has highly appreciated stock in a taxable brokerage account and is considering selling it to rebalance or simplify their finances, it may be worth pausing before they do that.
If they sell, they trigger a capital gains tax on the full gain — potentially tens of thousands of dollars. If they hold the asset until death, that entire gain disappears. Their heir inherits at the stepped-up basis and can sell immediately with no tax consequence.
This doesn’t mean never selling. There are good reasons to rebalance, manage concentration risk, or simplify an estate even at a tax cost. But for an 80-year-old with $300,000 in Apple stock that cost $15,000 in the 1990s, selling that position creates a capital gains bill somewhere between $42,750 and $57,000 depending on their bracket. Holding it until death eliminates that entire liability for their heirs. That’s a real decision worth having deliberately, not accidentally.
The same logic applies to the heir’s decision about what to do with inherited stock. There’s no rush to sell immediately. Once the basis steps up, you can hold the asset and let it continue growing — only the appreciation above the new stepped-up basis will be taxable when you eventually sell. If you want to hold the stock your parent owned for another 20 years, you can do that with a clean slate cost basis.
How It Interacts With the Rest of a Retirement Portfolio
For people thinking about how inherited assets fit into their broader retirement picture, the step-up rule changes which assets to think about spending down first. A taxable brokerage account with a high stepped-up basis is an extremely tax-efficient asset — gains from that point forward are taxed at capital gains rates (0%, 15%, or 20%), not ordinary income rates. That makes it potentially better to spend down traditional IRA money first in some scenarios, and preserve the inherited brokerage account for later when your effective tax rate may be lower.
This is one reason the total return vs. dividends conversation looks different once you factor in inherited assets — a stepped-up stock position is an extremely low-cost asset to hold and eventually sell, making the traditional case for dividend-paying stocks (generating "tax-efficient income") less relevant than it might otherwise be.
And if you’re in the window between inheriting assets and taking required minimum distributions, there may be Roth conversion opportunities worth considering. The right asset allocation between stocks and bonds in your various account types becomes even more important when you’ve added a new block of inherited taxable assets to manage alongside your existing retirement accounts.
What Could Change: The Political Risk
Worth noting, though with the caveat that I can’t tell you what Congress will do: the step-up in basis has been targeted for elimination or modification in various tax proposals over the years. Proposals to replace it with a "carry-over basis" (where heirs inherit the original cost basis rather than getting a step-up) have appeared in multiple recent budget proposals from both parties. None has passed as of this writing, and the rule remains fully intact. But for someone doing serious estate planning, it’s a rule worth monitoring — because if it changes, the tax implications of holding appreciated assets through death would shift dramatically.
The Practical First Step
If you’ve recently inherited a taxable brokerage account, the most important immediate step is finding out the cost basis the custodian has assigned. The brokerage should automatically record the date-of-death value as your new basis, but errors happen — particularly with older accounts that changed custodians over the years. Pull the account statements and verify the basis figure the custodian is showing you.
If you’re the one doing estate planning — thinking about what you’ll eventually leave to your kids — this is exactly the kind of analysis worth working through with a fee-only fiduciary advisor. Not a commissioned broker, but an advisor who gets paid to give you advice in your interest. The interaction between your IRA, your taxable brokerage, your Social Security timing, and the step-up rule on your appreciated holdings is complex enough that a few hundred dollars in advisory fees can identify tax savings in the five-to-six-figure range. NAPFA.org has a directory of fee-only advisors searchable by zip code — a solid starting point for finding someone qualified to help.
For building your own understanding before that conversation, Die With Zero by Bill Perkins challenges conventional wisdom about how to think about wealth transfer and timing. The Retirement Savings Time Bomb by Ed Slott goes deep on IRA distribution strategy and estate tax interaction — Slott is the clearest writer I know on inherited IRA rules and the tax implications of different account types at death. And for the broader estate planning picture, Estate Planning Basics by Denis Clifford is a practical plain-language guide that walks through wills, trusts, beneficiary designations, and how assets transfer — including how the step-up rule applies to different asset types.