What Is Exchange Boot?
In a 1031 exchange, you defer gain by reinvesting all your equity and taking on equal or greater debt. If you receive cash you don't reinvest, that's "cash boot" — taxable. If your mortgage on the replacement property is less than your mortgage on the relinquished property, the difference is "mortgage boot" (debt relief) — also taxable. Boot = cash received + net debt relief. To avoid boot, reinvest all proceeds and assume debt equal to or greater than what you had. Even a small amount of boot can trigger a meaningful tax bill — plan the numbers before you exchange.
Exchange boot is the taxable portion of a 1031 exchange — any cash you receive or net debt relief you get that isn't reinvested in the replacement property. The IRS treats boot as a partial sale, so you owe capital gains tax and depreciation recapture on that amount.
At a Glance
- What it is: The taxable portion of a 1031 exchange — cash or debt relief not reinvested
- Why it matters: Boot is taxed immediately — capital gains plus depreciation recapture on that amount
- Formula: Taxable boot = cash received + (relinquished debt − replacement debt)
- Avoidance: Reinvest all proceeds; take on equal or greater debt; add cash if needed
Taxable Boot = Cash Received + Net Debt Relief
How It Works
Cash boot. If you receive cash from the exchange and don't put it into the replacement property, that's taxable. Example: you sell for $400K, pay off $200K mortgage, net $200K. You buy a replacement for $350K with $150K down. You've taken $50K in cash ($200K − $150K) — that's $50K boot. You'll owe tax on it.
Mortgage boot (debt relief). If your replacement property has less debt than your relinquished property, the difference is "net debt relief" — the IRS says you've effectively received value (you owed more, now you owe less). That's taxable. Example: you sell with $200K mortgage, buy with $180K mortgage. You've reduced debt by $20K — $20K mortgage boot. Taxable.
Combined. Boot = cash boot + mortgage boot. In the first example, $50K cash boot. In the second, $20K mortgage boot. If you had both — $50K cash and $20K debt relief — you'd have $70K total boot. You'd owe capital gains tax and depreciation recapture on $70K.
Tax treatment. Boot is taxed as a partial sale. You allocate your cost basis and depreciation between the deferred portion and the boot. The boot portion is subject to capital gains rates and 25% depreciation recapture. It can add up quickly.
Strategies to avoid boot. (1) Reinvest all cash — put every dollar of net proceeds into the replacement. (2) Take on equal or greater debt — if you had $200K mortgage, get $200K or more on the replacement. (3) Add cash — if the replacement costs more than your proceeds, bring outside funds to avoid taking cash out. (4) In an improvement exchange, spend all proceeds on acquisition + improvements.
Real-World Example
Investor in Kansas City, Missouri. You sell a fourplex for $400,000. Mortgage payoff: $200,000. Closing costs: $15,000. Net proceeds: $185,000. You identify a six-plex for $450,000. You finance with $180,000 down and a $270,000 mortgage.
You have $185,000 in proceeds but only put $180,000 down. You're taking $5,000 in cash — $5,000 cash boot. Taxable.
You had $200,000 in debt on the relinquished property; you have $270,000 on the replacement. No mortgage boot — you've increased debt.
So your boot is $5,000. You'll owe tax on that $5,000 — capital gains plus recapture. At 25% recapture and 15% capital gains (blended), maybe $1,000–$1,500. Not huge, but avoidable — if you'd put the full $185,000 down (and borrowed $265,000), you'd have zero boot.
Another scenario: You sell for $400K, $200K mortgage, $185K net. You buy for $350K with a $150K mortgage. Down payment: $200K. You're putting $185K down and bringing $15K from outside. No cash boot. But: relinquished debt $200K, replacement debt $150K. $50,000 mortgage boot. Taxable. To avoid it, you'd need a $200K+ mortgage on the replacement — or a more expensive replacement that requires more debt.
Pros & Cons
- Understanding boot helps you structure exchanges to defer maximum gain
- Small amounts of boot may be acceptable if the deal is strong — you're just paying tax on that slice
- Knowing the formula lets you model before you commit
- Boot triggers immediate tax — no deferral on that portion
- Easy to accidentally create boot (e.g., taking a little cash for moving expenses)
- Mortgage boot is a common surprise — investors don't always realize that reducing debt is taxable
Watch Out
- Cash trap: Don't take any cash at closing — not for "expenses," not for "moving" — it's all boot
- Debt trap: A smaller mortgage on the replacement = mortgage boot; size your replacement debt to match or exceed relinquished debt
- Improvement exchange: If improvements cost less than planned, unspent proceeds = boot; have backup scope
- QI error: Ensure your qualified intermediary doesn't disburse cash to you — it should all go to the replacement
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The Takeaway
Exchange boot is the taxable slice of a 1031 exchange — cash or debt relief you didn't reinvest. To defer everything, reinvest all proceeds and take on equal or greater debt. Run the numbers before you exchange: cash boot + mortgage boot = your tax bill. A small oversight can cost you thousands.