Boot is the part of a 1031 exchange that does not qualify for tax deferral, and it shows up in two forms: cash boot and mortgage boot. Neither one disqualifies the whole exchange. Instead, boot is taxed as gain up to the amount received, while the rest of the transaction keeps its deferred treatment. Most investors who trigger boot did not intend to; it usually comes from replacing debt with too little debt, or pulling a small amount of cash out at closing without realizing what it costs.
Cash Boot: Money That Doesn't Make It Into the Exchange
Cash boot is any proceeds from the relinquished sale that end up in the investor's hands instead of moving through the qualified intermediary into the replacement purchase. That includes an intentional cash-out at closing, but it also includes smaller amounts that are easy to miss, such as interest earned on funds held by the qualified intermediary, prorated rent or security deposits from the sold property that get disbursed directly, or leftover exchange funds after the replacement purchase closes at a lower price than expected. Any of these count as boot and get taxed as gain, even if the amount is small relative to the overall transaction.
Mortgage Boot: Trading Down on Debt
Mortgage boot, sometimes called debt-relief boot, happens when the debt paid off on the relinquished property is larger than the debt taken on for the replacement property, and the investor doesn't make up that difference with additional cash into the exchange. An investor who pays off a $600,000 mortgage on the property sold and only takes on $400,000 of new debt on the replacement has $200,000 of mortgage boot, unless they contribute $200,000 of their own outside cash to cover the gap. This is the boot category that catches investors off guard most often, particularly when they're deliberately buying a smaller or lower-leverage replacement property.
Why Long Island Deals Create Boot Risk in Both Directions
Nassau and Suffolk closing costs, transfer taxes, and attorney fees are commonly paid from sale proceeds before they ever reach the qualified intermediary, and if those costs are paid from funds that should have moved into the exchange, the shortfall can show up as unintended cash boot. On the debt side, an investor exchanging out of an older, more leveraged multifamily property into a lower-leverage industrial asset along the LIE or Route 110 corridor, a common move for someone reducing management exposure, needs to run the debt math before signing a replacement contract, not after, since mortgage boot is calculated on the numbers at closing, not on intent. Village and town transfer taxes across Nassau and Suffolk vary enough from one municipality to the next that a closing statement drafted early in a deal can understate what actually leaves the proceeds before they reach the qualified intermediary, so a revised statement close to closing is worth checking against the original exchange budget.
How to Structure Around Boot Before It Happens
Debt on the replacement property needs to equal or exceed debt paid off on the relinquished property, or the investor needs to bring outside cash into the exchange to cover the difference; there is no other way to avoid mortgage boot once the closing numbers are set. Any leftover cash sitting with the qualified intermediary after the replacement purchase should be treated as taxable, not as a bonus, and factored into the return before it happens rather than discovered on a 1099 the following year. Running the debt and cash numbers with a CPA before a replacement contract is signed, not after closing, is the difference between a clean deferral and a surprise tax bill on part of the gain.
Common 1031 Exchange Questions
Does receiving any boot disqualify your entire 1031 exchange?
No, boot does not disqualify the exchange. It is taxed as gain up to the amount of boot received, while the remaining value that stayed inside the exchange keeps its tax-deferred treatment.
What's the difference between cash boot and mortgage boot?
Cash boot is proceeds that land in the investor's hands instead of moving through the qualified intermediary into the replacement purchase. Mortgage boot is debt relief, meaning the replacement property carries less debt than the relinquished property did, without additional outside cash added to cover the gap.
Can you avoid mortgage boot by adding cash instead of taking on more debt?
Yes, bringing outside cash into the exchange to match the reduction in debt avoids mortgage boot even if the new loan amount is smaller. The requirement is that debt plus added cash on the replacement side equals or exceeds the debt paid off, not that the debt itself stays the same.
Is leftover money held by the qualified intermediary automatically boot?
Yes, any exchange funds that remain with the qualified intermediary after the replacement purchase closes, including interest earned on those funds, are treated as boot and taxed as gain once they're disbursed back to the investor.
Do you need to worry about boot if you're buying a bigger, more expensive property?
Boot risk is much lower when an investor buys equal or greater value with equal or greater debt, since there's usually no leftover cash and no debt-relief gap. Boot tends to show up when an investor trades down in price, debt, or both.
