1031 Exchange Boot

The governing rule is one sentence: you recognise the lesser of your realised gain or the net boot you received. Boot can never make you report more than you actually made, and gain is never deferred past the boot you took.

Most sellers meet boot for the first time on a return, in March, months after the exchange closed and long after anything could have been done about it.

Run your own numbers in the 1031 calculator → It computes your boot both ways, splits it into the buckets below, and shows what each fix is actually worth.

The two kinds

Cash boot is money. Cash taken at the closing table, or — far more often — proceeds the qualified intermediary could not spend because the replacement property cost less than the one you sold. Unspent money sitting at the QI on day 181 is cash boot whether you intended it or not.

Mortgage boot is debt relief. You carried a $1.4M loan; the replacement carries $400k. You were released from $1M of obligation. Being relieved of debt counts as receiving value, so it is boot — even though no money moved.

The netting rule only works one way

This is where experienced investors still get hurt.

• Cash you bring from outside the exchange does offset mortgage boot, dollar for dollar
• Exchange expenses — commission, escrow, title, the QI fee — do reduce boot
• New debt on the replacement does NOT offset cash you received

Pocket $100,000 at closing while taking on $200,000 more debt than you shed, and the extra leverage feels like it should cover it. It does not. The whole $100,000 is taxable. Cash boot and mortgage boot net separately, and the traffic runs in only one direction.

Boot is taxed worst-first

Recognised gain is not taxed at a single rate. It fills three buckets, starting with the most expensive:

1. §1245 depreciation recapture — ordinary income, up to 37% federal
2. Unrecaptured §1250 gain — 25%, under §1(h)(1)(E)
3. Long-term capital gain — 0/15/20%, plus 3.8% NIIT

A modest boot on a heavily depreciated building can be entirely ordinary income. The first dollars out are always the expensive ones.

The phantom tax bill

This is the problem nobody warns about, and it is the most common one.

A seller trades down, sheds debt, and reinvests every single dollar. Nothing comes home. Here is what that looks like on a real set of numbers — $3M sale, $1.4M of debt shed, into a $2.6M replacement carrying only $400k:

He did everything right. He reinvested all of it. He owes $81,963, payable in April, out of his own savings, on a transaction where he never touched a dollar.

That is phantom income, and debt relief is the most reliable way to create it.

See whether your exchange throws one → — the calculator puts cash received and tax owed side by side, which is the only comparison that matters here.

The suspended losses you may already have

Here is the part most explanations get backwards.

A §1031 exchange is not a fully taxable disposition, so §469(g)(1) does not release your suspended passive losses. They do not free up. They carry over and attach to the replacement property.

But recognised boot is passive activity income — so the suspended losses from that activity can be deducted against it.

In the case above, $500,000 of suspended passive losses absorbed the entire $220,000 of boot. The $81,963 bill went to zero, and $280,000 of losses carried forward to the replacement. Losses that had been sitting on the return for years doing nothing.

Anyone who has owned a rental through a few bad years should check this before assuming the boot is unavoidable. Enter your suspended loss balance → and the calculator applies it to the most expensive layer first.

Why a note usually will not save you

The instinct is to take the boot as seller financing and spread it over years. It rarely works, for two reasons.

§453(i) recognises depreciation recapture in full in the year of sale, even on the installment method. The ordinary slice cannot move. A note only ever reaches the 25% and long-term layers.

The 25% layer is flat. Twenty-five percent in year one is twenty-five percent in year ten. Spreading only pays when the boot is large enough to fall out of 20%-plus-NIIT into 15%.

On a $420,000 boot that was mostly recapture, spreading it across ten years saved $2,343 — six tenths of one percent. On a $1.36M boot that was all long-term gain, the same structure saved $71,177. The difference is size and character, not cleverness. The calculator tells you which one you have — and says plainly when a note is not worth it.

Cost segregation makes it worse

A cost segregation study moves basis out of the 39-year shell into 5-, 7- and 15-year property. That converts future §1250 depreciation — 25%, and eligible for installment treatment — into §1245, which is ordinary income and frozen into year one by §453(i).

Cost segregation saves real money while you hold the building and quietly damages the exit. It is often still the right call. It is never mentioned by the firm selling the study.

The calendar creates boot

The replacement must be received by the earlier of 180 days or your return due date including extensions. A closing on 20 November loses 34 days — the window snaps back to 15 April — unless Form 4868 is filed.

Add the identification rules — three properties, or any number within 200% of value, or 95% of what you identify must actually close — and sellers routinely get forced into trading down on day 46. The boot was created by the calendar, not by choice.

California keeps its claim forever

Deferred California-source gain stays California's when the replacement is out of state. FTB Form 3840 must be filed every year until that gain is recognised — including years you owe California nothing else, and after you have moved away. The FTB cross-references federal Form 8824 and issues notices automatically when the 3840 is missing.

What actually kills boot

A Delaware Statutory Trust. Under Rev. Rul. 2004-86 a DST interest is treated as a direct interest in real property, so it qualifies as replacement property — and it does two jobs at once.

It absorbs leftover cash in any dollar amount, so there is no need to find a whole building that happens to cost the right number. And because most DSTs carry non-recourse leverage, your share of that debt replaces the debt you shed — killing mortgage boot at the same time.

On the $3M deal above: $220,000 of equity into a 50%-leveraged DST bought $440,000 of property carrying $220,000 of debt. Recognised boot went from $420,000 to zero, and $158,163 of tax went with it.

The honest order is DST first, suspended losses second, a note third, cash last.

Model the DST allocation → — set how much of the leftover goes into the trust and at what leverage, and watch the recognised boot move.

Where a §453 installment sale actually belongs

Not here. A structured installment sale is a poor answer to boot and an excellent answer to a different question: do you want to still be a landlord?

A DST solves the tax and keeps you in real estate — with no control, for the life of the trust. An installment sale gets you out entirely, spreads the tax across years you choose, and pays you on a schedule. Those are different problems. Anyone who sells you one as the answer to the other is not doing the arithmetic.

Run your own numbers first. If the boot is small and mostly recapture, take the cash and stop reading. If it is large, or if you are tired of tenants, the structure is worth an hour.

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Run it on your own deal

The 1031 exchange calculator takes what you sold, what you are buying, and the debt on each side, then gives you:

• your cash boot and mortgage boot under the real netting rules
• the character split — §1245, §1250 and long-term — because that decides which fixes can help
• the phantom bill: tax owed against cash actually received
• what a DST, your suspended losses, or an installment note each do to it, in dollars
• your true deadline, including the return-due-date trap that shortens a late-year exchange
• the California clawback warning if you are selling here and buying elsewhere

It is free, nothing is saved, and it will tell you to take the cash when that is the right answer.

Related: unrecaptured §1250 gain calculator · depreciation recapture calculator