Boot is the portion of a 1031 exchange that does not qualify for tax deferral, meaning it gets taxed as if you had sold that portion outright even though the rest of the exchange defers cleanly. The word is not a technical accident; it comes from the plain-English sense of getting something extra thrown in on top of a trade, and that extra piece is exactly what the IRS treats as taxable gain rather than deferred gain.
Most Miami exchangers who end up with boot did not plan for it. It usually shows up because the replacement property cost less than the relinquished property sold for, or because the new financing came in lower than the old mortgage, both of which quietly leave value on the table that the exchange structure cannot shelter.
Cash Boot
Cash boot is the simplest version: any exchange proceeds that come back to you in cash rather than being reinvested into the replacement property. Sell a Doral warehouse for $3 million and buy a replacement for $2.7 million, and the $300,000 difference that lands in your pocket, even briefly, is cash boot, taxable in the year of the exchange regardless of what you eventually do with it. It does not matter that the money passed through your qualified intermediary first or that you only held it for a few days before reinvesting it elsewhere.
Mortgage Boot and Debt-Relief Boot
Mortgage boot works the same way but with debt instead of cash. If the mortgage you pay off on the relinquished property is larger than the mortgage you take on for the replacement, that reduction in debt is treated as if you received cash, even though no money physically changed hands. A Kendall multifamily owner who pays off a $1.8 million loan and only takes on $1.2 million in new financing has $600,000 of debt-relief boot, taxable the same way cash boot would be, unless that gap is closed with additional cash into the deal.
Both Boots Can Show Up in the Same Exchange
Cash boot and mortgage boot are not mutually exclusive, and a single exchange can generate both at once if the replacement property is both cheaper and less leveraged than the relinquished one. Adding cash into the deal can offset debt-relief boot, but cash you take out of the deal cannot be offset by taking on more debt elsewhere; the two categories move in only one direction toward avoiding tax, not both.
How Miami Exchangers Typically Avoid It
The two rules that keep boot out of an exchange are straightforward even though following them under deadline pressure is not: buy a replacement property equal to or greater in value than what you sold, and carry equal or greater debt on the replacement than you paid off on the relinquished property. When a South Florida owner cannot find a suitable property at full value before day 180, adding cash to increase the purchase price, or accepting a slightly higher loan amount than strictly needed, are both common ways to close the gap rather than accept a partially taxable exchange.
Common 1031 Exchange Questions
What is the difference between cash boot and mortgage boot?
Cash boot is exchange proceeds that come back to you as money rather than being reinvested. Mortgage boot is a reduction in debt, where the loan on the replacement property is smaller than the loan paid off on the relinquished property.
Can I avoid mortgage boot by simply bringing extra cash to the closing?
Yes. Adding cash into the deal can offset a debt-relief gap, but taking cash out of the deal cannot be offset by taking on additional debt elsewhere.
Is boot always a bad outcome for an exchanger?
Not necessarily. Some exchangers accept a limited amount of boot deliberately, using it to pull a small amount of cash out of a sale while still deferring the majority of the gain on the rest of the exchange.
How is boot actually taxed?
Boot is taxed in the year of the exchange, generally at capital gains rates up to the amount of realized gain, and it does not receive the deferral treatment the rest of a properly structured exchange gets.
Does boot only happen when the replacement property is cheaper?
A lower purchase price is the most common cause, but boot can also appear when the new mortgage is smaller than the old one, even if the purchase price itself is roughly equal.
Who calculates whether an exchange will generate boot?
A qualified intermediary or CPA typically runs the numbers before closing, comparing the relinquished sale price and debt payoff against the replacement purchase price and new financing to flag any gap early.
