California 1031 Exchange Rules: Form FTB 3840 and Deferred-Gain Tracking

California has a long memory. If you sell a California rental, do a clean 1031 exchange, and roll the gain into a replacement property in Texas or Nevada, you did not walk away from California tax. You deferred it, and California intends to follow that gain wherever it goes. The mechanism it uses to keep watch is Form FTB 3840, and most investors do not learn about it until a notice shows up asking why they stopped filing.

This is the part of a state-line 1031 exchange that the federal rules do not prepare you for. The IRS side ends when you file Form 8824 for the year of the exchange. California’s side does not. It keeps running, year after year, until you finally recognize the gain on a California return.

When California deferred-gain tracking applies

The tracking rule kicks in under a specific set of facts. You relinquish real property located in California. You acquire replacement property located outside California. And California-source gain stays deferred because the exchange qualified under Section 1031.

That combination is what triggers the obligation. If both properties are in California, there is nothing to track across a state line. If you relinquish out-of-state property, California was never the source of the gain. It is the move out of California, with deferred gain attached, that puts you on California’s radar.

You can see how this plays out by entering an out-of-state replacement in the 1031 exchange calculator. The tool flags the “California Deferred-Gain Tracking” scenario when your relinquished property is in California and your replacement sits elsewhere, so you know the annual filing applies before you ever reach a closing table.

What Form FTB 3840 is for

Form FTB 3840 is California’s Like-Kind Exchanges form. Its job is narrow but persistent: it tells California that a chunk of California-source gain is sitting inside an out-of-state property, deferred but not gone.

You file it for the taxable year of the exchange, the same year you report the federal exchange on Form 8824. That first filing establishes the deferred California-source gain or loss and the replacement property it landed in.

Then you keep filing it. Form FTB 3840 must be filed for each subsequent year, generally until the California-sourced deferred gain or loss is recognized on a California return. This is the requirement people miss. It is not a one-time disclosure. It is an annual information return that rides along with the deferred gain for as long as the deferral lasts.

The most common point where the obligation ends is when you later sell the out-of-state property in a taxable sale, recognize the gain, and report California’s share. At that point there is nothing left to track, and the annual filing stops. Until then, skipping a year is how you draw a notice.

Why future gain recognition still touches California

Here is the logic that makes the whole thing hold together, and it is worth understanding rather than just complying with.

The source of gain is fixed at the moment the gain is realized. When you sold the California property, that gain was California-source income. A 1031 exchange defers when you recognize that gain. It does not change where the gain came from. So the California-source character is preserved regardless of how many years pass or how many states the property moves through.

That is why California eventually collects its share. Say you exchange a California rental into a Nevada property and hold it for a decade. Nevada has no state income tax, which is often the whole point. But the deferred portion that traces back to the original California sale keeps its California-source label the entire time. When you finally sell the Nevada property in a taxable transaction, California can tax the deferred California-source gain that surfaces. The annual Form FTB 3840 is how the state keeps the paper trail intact so it can do exactly that.

I will keep this part conceptual on purpose. The deferred-gain figure depends on your specific basis, debt, and any boot, and it is not a fixed number. The point to hold onto is the principle: California tracks the deferred gain until it is recognized, and the move to a no-tax state does not erase the California claim.

State tracking and closing withholding are two different things

This is where a lot of confusion lives, so it is worth pulling apart cleanly. There are two separate California obligations in play, and they do different jobs at different times.

State tracking is the annual reporting obligation. That is Form FTB 3840, filed every year until the deferred gain is recognized. It does not collect any tax by itself. It just keeps California informed.

Closing withholding is a one-time event at the sale. That is California real estate withholding, reported on Form 593, and it is a prepayment against the tax that might be due, collected at closing. It happens once, at the transaction, not every year.

These are not the same thing, and one does not satisfy the other. You can have a clean exchange with zero withholding at closing and still owe years of Form FTB 3840 filings afterward.

How the withholding side actually works

For a clean full-deferral exchange with no taxable boot, your estimated California closing withholding is $0. The exchange qualifies for an exemption from withholding, and you confirm that exemption with your qualified intermediary at closing. There is no tax to prepay because, by design, you are deferring the gain rather than recognizing it.

California real estate withholding generally applies only when there is taxable boot above $1,500, at a 3.33% rate. Boot at or below $1,500 results in $0 withholding.

A worked example makes the threshold concrete. Suppose a partial exchange produces $50,000 of taxable boot, meaning you pulled out cash or reduced debt and that portion does not qualify for deferral. The estimated California withholding is the boot above the threshold times the rate: ($50,000 minus the $1,500 threshold) times 3.33%, which comes to $1,615.05. That is a prepayment against the California tax on the recognized boot, collected once at closing.

Notice what this example does not change. Even with $1,615.05 withheld at closing on the taxable boot, the deferred portion of the gain that rolled into the out-of-state replacement still has to be tracked annually on Form FTB 3840. The withholding handled the piece you recognized now. The tracking handles the piece you did not.

What to actually do

Two habits keep you out of trouble here.

First, calendar the annual filing. The year you do a California-to-out-of-state exchange, set a recurring reminder to file Form FTB 3840 with your California return every year. Treat it like a standing obligation, because that is what it is, until the gain is recognized.

Second, keep the two ideas separate in your own head. Withholding at closing is a once-and-done prepayment tied to any taxable boot. The Form FTB 3840 tracking is an annual report that has nothing to do with whether anything was withheld. Confusing the two is how people assume their California obligation ended at the closing table when it was only beginning.

None of this should talk you out of a 1031 exchange across state lines. The deferral is still real and still valuable. You just need to know that leaving California with deferred gain comes with a filing that follows you, and that California has set things up to collect its share whenever the gain finally surfaces. This is educational, not tax advice, so confirm the specifics for your situation with a California tax professional.

Sources

California FTB, Form 593 real estate withholding instructions
California FTB, Form FTB 3840 California Like-Kind Exchanges
California FTB, Real estate withholding
IRS, Like-Kind Exchanges Real Estate Tax Tips

Frequently Asked Questions

When does California require Form FTB 3840?

California requires it when you relinquish real property located in California, acquire replacement property located outside California, and the California-source gain stays deferred under a 1031 exchange. That specific combination, California property out, out-of-state property in, with deferred gain, is what triggers the filing. If both properties are in California, or the relinquished property was outside California, the tracking form does not apply.

How long do I have to keep filing FTB 3840?

You file it for the year of the exchange and for each subsequent year, generally until the California-sourced deferred gain or loss is recognized on a California return. The most common ending point is when you later sell the out-of-state replacement in a taxable sale and report California’s share. Until that happens, it is an annual obligation, and skipping a year is how you draw a notice.

Is FTB 3840 the same as Form 593 withholding?

No. They are two separate things. Form FTB 3840 is an annual information return that tracks the deferred gain year after year and collects no tax by itself. Form 593 is real estate withholding, a one-time prepayment collected at closing on any taxable boot. You can owe years of FTB 3840 filings even when your closing withholding was $0.

Will California eventually tax my deferred gain?

Yes, when you recognize it. The source of the gain is fixed when it is realized, so gain from the original California sale keeps its California-source character even after you move it into a property in a no-tax state like Nevada or Texas. When you later sell that replacement in a taxable transaction, California can tax the deferred California-source portion. Form FTB 3840 is how the state keeps the trail intact to do so.

What is the withholding on taxable boot in a California exchange?

For a clean full-deferral exchange with no boot, estimated California closing withholding is $0. When there is taxable boot above $1,500, withholding generally applies at 3.33% on the amount above the threshold. For example, $50,000 of taxable boot produces ($50,000 minus $1,500) times 3.33%, or $1,615.05. Boot at or below $1,500 results in $0 withholding.