Boot is the portion of an exchange that does not qualify for tax deferral, and it shows up in two forms: cash boot and mortgage boot. A 1031 exchange defers gain only to the extent the investor trades equal or up in both value and debt. Falling short in either direction creates boot, and boot is taxed as gain in the year of the exchange even though the rest of the transaction defers cleanly. Understanding where boot comes from matters more before a replacement contract is signed than after, because by then the numbers are already locked in.
Cash Boot Explained
Cash boot is the most direct form: any cash or cash equivalent the investor receives during the exchange rather than reinvesting into replacement property. This includes leftover exchange funds the qualified intermediary returns after closing, prorated rent credits paid outside the exchange account, and any seller concession structured as cash back to the investor. An investor who buys a slightly cheaper replacement property than the one sold and pockets the difference has created cash boot equal to that difference, whether or not the money physically passes through their hands before it reaches the intermediary.
Mortgage Boot and Debt-Relief Boot
Mortgage boot skips the cash step entirely, which is what makes it easy to overlook. It shows up whenever the payoff on the relinquished property's mortgage is bigger than the new loan placed on the replacement property. An investor who pays off a $400,000 mortgage on a Charleston property and buys a replacement with only $250,000 in new debt has $150,000 of debt relief, and that relief is treated as boot unless offset with additional cash invested into the deal. This is the boot category that trips up investors who are trying to reduce leverage as part of the same transaction, since paying down debt and deferring gain pull in opposite directions.
How Boot Gets Created Even When You Do Not Take Cash
Boot does not require an investor to receive a check. Closing costs paid from exchange funds that are not qualifying transaction costs, non-like-kind property received as part of a deal, and even certain prorations can generate boot without ever showing up as cash in a bank account. A common example in South Carolina closings is a seller credit for repairs that gets routed through the closing statement in a way the qualified intermediary was not structured to absorb, creating a small amount of boot that the investor did not intend to trigger.
Calculating Boot Before You Sign a Replacement Contract
Because boot is determined by the relationship between the relinquished and replacement transaction values and debt levels, it can be projected before a replacement contract is signed. Running the numbers on price, expected new financing, and remaining exchange funds ahead of an offer lets an investor structure the purchase to fully absorb the exchange proceeds rather than discovering a boot exposure at closing. This matters most when an investor is comparing multiple South Carolina replacement candidates that carry different price points or financing terms, since the boot exposure can differ meaningfully between two properties that otherwise look similar.
Boot and South Carolina's Capital Gains Treatment
South Carolina taxes capital gains as ordinary income under its graduated income tax, but the state allows a 44% deduction against net capital gain for individual taxpayers who meet the required holding period. Boot recognized in an otherwise deferred exchange is still capital gain, so it is generally eligible for that same state-level deduction, in addition to whatever federal treatment applies. That does not eliminate the tax on boot, it only reduces the effective state rate applied to the recognized portion, which is why minimizing boot at the structuring stage remains worthwhile even for investors who plan to hold the replacement property long term.
Frequently Asked Questions
Is boot always cash the investor physically receives?
No. Mortgage boot from reduced debt on the replacement property, and certain non-qualifying costs paid from exchange funds, can create boot without any cash landing in the investor's hands.
How can mortgage boot be avoided?
By matching or exceeding the debt paid off on the relinquished property with debt on the replacement property, or by contributing additional cash into the deal to offset the reduced debt.
Does boot cancel the whole exchange?
No. Boot is taxed as gain up to the amount of the boot, while the rest of the exchange still defers normally. It reduces the benefit rather than eliminating it.
Can boot come from closing cost allocations?
Yes. Paying non-qualifying costs, such as certain prorations or credits, from exchange funds can create boot even when the investor never intended to take cash out of the deal.
Does South Carolina's capital gains deduction apply to boot?
Boot is treated as recognized capital gain, so it is generally eligible for South Carolina's 44% net capital gain deduction for qualifying individual taxpayers, the same as other recognized gain.