Stepped-Up Basis in a California Trust, Explained

Stepped-Up Basis in a California Trust, Explained

Stepped-up basis is the rule that resets an inherited asset’s cost basis to its fair market value on the date the owner died, under Internal Revenue Code § 1014. Whatever gain built up while your parent owned the house or the stock portfolio simply disappears for tax purposes. Sell that asset soon after death for close to its date-of-death value, and there’s often little or no capital gains tax owed at all.

For the whole decision, including Prop 19, the step-up, and who has authority to sell, see what to do with an inherited house in California.

I bring this up first because a trustee who gets basis wrong can hand beneficiaries a tax bill that never needed to exist. Get it right, and a house that gained $600,000 in value over thirty years can sometimes be sold with nothing owed to the IRS. This is one of the first things you need to understand before you list a house, distribute a brokerage account, or file a fiduciary income tax return.

What “basis” is and why it matters

Basis is the number the IRS uses to measure gain when an asset sells. Say your father bought his house in 1985 for $80,000, and it’s worth $900,000 the year he dies. If he’d sold it the year before he died, he would have owed capital gains tax on $820,000 of appreciation, the difference between what he paid and what he sold it for. That’s a real number, and at combined federal and California rates it could easily mean a six-figure tax bill.

Die owning the house instead, and § 1014 resets the basis to $900,000, its fair market value on the date of death. The $820,000 of built-in gain is gone. If the trust turns around and sells the house for $910,000 a few months later, the taxable gain is $10,000, not $830,000. That’s the entire mechanism, and it’s the single biggest tax advantage built into inheriting property rather than receiving it as a lifetime gift, where the giver’s original basis carries forward instead of resetting.

Why the trustee is the one who has to get this right

The trustee reports the sale to the IRS, whether that happens on the trust’s own fiduciary return (Form 1041) or by passing the numbers through to beneficiaries on a Schedule K-1. Get the basis wrong in either direction and someone pays for it. Understate the stepped-up value and the trust overpays tax on gain that was never real. Overstate it, or skip the appraisal and guess, and the trust underreports gain, which creates exposure for the trustee personally and for every beneficiary who received a distribution based on those numbers.

The starting point is always the same question: what was the asset actually worth on the date the person died? For real property, that means a qualified, dated appraisal, not a Zillow estimate, not a real estate agent’s ballpark, and not the county assessor’s number, which reflects Proposition 13 assessed value and can be wildly different from market value. For publicly traded securities, the basis is usually the average of the high and low trading price on the date of death. An estate that files a federal estate tax return (Form 706) can sometimes elect an alternate valuation date six months out instead, but only when the election lowers both the gross estate and the estate tax (IRC § 2032), and unlisted or thinly traded assets need an appraisal.

Get the appraisal early. Waiting until escrow opens on a home sale is waiting too long, because by then the appraiser is valuing the property as of today, not as of the date your parent died, and you’ve lost the clean record you need to defend the basis if the IRS ever asks. I walk through how to get that appraisal done correctly, and everything else it affects beyond basis, on the date-of-death appraisal page.

Community property gets a bigger step-up than other forms of ownership

This is where California trustees run into the biggest trap, and it’s a trap that costs real money. If a married couple owned their home as community property and one spouse dies, both halves of the property step up to fair market value, not just the deceased spouse’s half. That’s the full step-up rule under IRC § 1014(b)(6), and California is one of the small number of community property states where it applies.

Other forms of ownership don’t get that benefit. A decedent’s separate property gets a full step-up on the decedent’s interest, but a surviving spouse’s own separate property gets none. A surviving joint tenant who wasn’t married to the decedent, or property held in unequal shares, only steps up the portion that belonged to the person who died. The rest keeps its original, lower basis, and whoever holds it inherits the tax problem along with the asset.

Run the numbers on a real example. A couple buys a house in 1990 for $150,000 and holds it as community property for the marriage. One spouse dies when the house is worth $1,150,000. As community property, the entire basis resets to $1,150,000, and a prompt sale at that price triggers no capital gains tax at all. Change one fact, say the house was actually the surviving spouse’s separate property, bought before the marriage, and nothing resets when the other spouse dies, because the decedent never owned it. Sell the same house for the same $1,150,000, and the gain is measured from the original $150,000 basis, which means meaningful capital gains tax. Same house, same sale price, a tax difference that can run into six figures, entirely because of how the asset was characterized.

That gap is why characterizing an asset correctly, before assuming it qualifies for the full step-up, matters so much. I go through exactly how that analysis works, and where trustees get it wrong, in community property versus separate property step-up in California, which is worth reading in full before you make any assumptions about basis on a married couple’s assets.

When the step-up doesn’t apply at all

Not everything in a trust gets this treatment. Retirement accounts, IRAs, 401(k)s, and similar tax-deferred accounts don’t get a stepped-up basis. They carry embedded income tax liability regardless of when the owner dies, and a beneficiary who inherits an IRA will owe ordinary income tax as it’s distributed, no step-up available. Assets already sitting in an irrevocable trust that the decedent didn’t control may not qualify either, depending on how the trust was drafted and whether the assets were includable in the decedent’s taxable estate. And property your parent gave away during life, rather than held until death, keeps the giver’s original basis under IRC § 1015. No step-up, ever, for a lifetime gift.

This is one more reason a trustee shouldn’t guess at basis or lean on whatever old cost records the family happens to have lying around. The rules turn on ownership, timing, and asset type, and getting any one of those three wrong changes the tax outcome, sometimes dramatically.

Asset or situation	Stepped-up basis?
Community property when a spouse dies	Yes, both halves step up (IRC § 1014(b)(6))
Separate property	The decedent’s separate property gets a full step-up; a surviving spouse’s own separate property gets none
A surviving joint tenant who wasn’t married to the decedent	Only the portion that belonged to the person who died
IRAs, 401(k)s and similar tax-deferred accounts	No, they carry embedded income tax
Property given away during life	No, the giver’s original basis carries forward (IRC § 1015)
Assets in an irrevocable trust the decedent didn’t control	May not qualify, depending on how the trust was drafted and whether the assets were includable in the taxable estate

How this connects to Prop 19 and property tax

Stepped-up basis is a federal capital gains concept under IRC § 1014. It has nothing to do with California’s Proposition 19, which governs whether an inherited home keeps its parent’s property tax assessment. They’re two entirely different tax systems that happen to collide on the same house at the same time. A house can get a full stepped-up basis for federal capital gains purposes and still trigger a full property tax reassessment under Prop 19, or vice versa. I cover the property tax side, including the narrow requirements for keeping a parent’s tax base, in the Prop 19 parent-child exclusion.

Document the value anyway

Stepped-up basis is one of the better breaks in the tax code, but it isn’t a reason to relax about paperwork. The IRS can and does ask for proof of date-of-death value years after the fact, and “we think it was worth around that much” is not proof. If you sell without a documented appraisal, you’re gambling with someone else’s tax return, not just your own judgment call. And basis is only step one. Characterization, appraisal timing, and how the sale flows through the trust’s accounting to beneficiaries under Probate Code § 16062 all have to line up too.

Talk to a real California estate attorney

If you’re a trustee and you’re not sure whether an asset qualifies for a full or partial step-up, don’t guess before a sale closes. I’ll look at how the asset was held, get the valuation timeline right, and tell you exactly what the trust owes, if anything, before you sign anything with a buyer or the IRS.

Talk to Eric Ridley is a free 30-minute consultation by phone or Zoom, anywhere in California. Or call (805) 244-5291. You’ll leave knowing where you stand, whether or not you hire me.

Related reading: Community property vs. separate property step-up · Capital gains tax on inherited property in California · Getting the date-of-death appraisal right

Frequently asked questions

What does stepped-up basis mean for a California trust?

Stepped-up basis means an asset’s cost basis resets to its fair market value on the date the owner died, under IRC § 1014. Any gain that built up during the owner’s life disappears for tax purposes. If a trust sells the asset soon after death near that value, there’s often little or no capital gains tax owed.

How do I get the date-of-death value for a stepped-up basis?

For real property, you need a qualified appraisal dated as of the death, not a Zillow estimate or the county assessor’s figure. For publicly traded securities, it’s typically the average of the high and low trading price on the date of death. Estates that file a federal estate tax return can sometimes elect an alternate valuation date six months later, but only if it lowers both the gross estate and the tax. Get the appraisal early.

Does everything in a trust get a stepped-up basis?

No. Retirement accounts like IRAs and 401(k)s never get a step-up; they carry embedded income tax regardless of when the owner dies. Property gifted during life keeps the giver’s original basis under IRC § 1015. And some assets already sitting in an irrevocable trust may not qualify, depending on how it was structured.

Why do trustees need to worry about stepped-up basis before selling a house?

The trustee reports the sale to the IRS, either on the trust’s own return or by passing gain through to beneficiaries on a Schedule K-1. Use the wrong basis and the trust either overpays tax it never owed or underreports gain, which creates exposure for the trustee and every beneficiary who received a distribution.

Does community property get a bigger step-up than other kinds of ownership in California?

Yes. Under IRC § 1014(b)(6), when one spouse dies, both halves of community property step up to fair market value, not just the deceased spouse’s half. A decedent’s separate property gets a full step-up, but a surviving spouse’s own separate property gets none, and joint tenancy with a non-spouse steps up only the decedent’s share. In California that difference is often worth hundreds of thousands of dollars.

This is general information about California law, not legal advice for your situation.