By the 45th day of a 1031 exchange, the taxpayer must have committed in writing to what they might buy. Not what they will buy — the identification is not a purchase obligation — but the universe of property from which the replacement must come.
After day 45, that universe is fixed. Property outside it generally cannot qualify, no matter how much better it is or how badly the identified alternatives fall through. This makes the identification one of the most consequential documents in the transaction, and it is routinely treated as an administrative formality.
The three alternatives
Treasury regulations provide three ways to satisfy the identification requirement. The taxpayer chooses one; they are alternatives rather than cumulative requirements.
The three-property rule
Identify up to three properties, regardless of their combined value. The taxpayer may then acquire one, two, or all three.
This is the most commonly used alternative, for a simple reason: value is irrelevant. A taxpayer selling a modest property may identify three substantially more expensive ones without violating anything. It provides genuine optionality — a preferred property and two alternatives — without requiring anyone to track a ceiling.
The 200% rule
Identify any number of properties, provided their aggregate fair market value does not exceed 200% of the aggregate value of the relinquished property.
This suits a taxpayer assembling a portfolio of smaller assets — several DST interests, or multiple small properties — where three identifications is too restrictive. The constraint is the value ceiling, computed across everything identified.
The arithmetic is unforgiving: identify four properties totaling 201% of the relinquished value, and the rule is failed. Because valuations of unidentified-yet-unpurchased property involve estimation, prudent practice leaves margin rather than approaching the limit.
The 95% rule
Identify as many properties as desired, at any value, provided the taxpayer actually acquires at least 95% of the aggregate value identified.
This is technically an escape from both limits and practically a trap. A taxpayer who identifies broadly and then acquires only some of it fails the 95% threshold — and if the identification also breached the three-property and 200% limits, there is no fallback. The identification fails entirely.
The 95% rule is genuinely useful only where the taxpayer is confident of acquiring essentially everything identified. Practitioners generally treat it as a last resort rather than a planning tool.
What a valid identification requires
The regulations impose specific requirements, and each is a place where identifications fail:
In writing. Oral identification does not count.
Signed by the taxpayer.
Delivered before the end of day 45 to a person involved in the exchange who is not a disqualified person. In practice this means the qualified intermediary. Delivering it to one’s own attorney or accountant — who may be a disqualified person by virtue of the relationship — is a classic and avoidable error. Confirm the recipient with the intermediary.
Unambiguously described. Real property is typically identified by legal description or unambiguous street address. “A property in Dallas” is not an identification. “A four-plex on Elm Street” is not an identification. Ambiguity is resolved against the taxpayer.
Fractional interests specified by percentage. For a DST interest or a tenant-in-common position, the identification should specify the percentage interest being identified, not merely the property.
Revocable within the period. An identification may be revoked and replaced within the 45 days, in a signed writing delivered the same way. After day 45, it is fixed.
The strategy of identifying
The identification is where a good exchange builds resilience, and there are a few reliable patterns.
Always identify alternatives. The three-property rule permits three at no cost in value terms. Identifying only the property under contract means that if the seller walks, the appraisal disappoints, or financing fails, the exchange has no path forward. A single identification is an unhedged position on a transaction the taxpayer does not fully control.
Consider a DST as a backup. This is why DSTs feature heavily in exchange planning. A DST interest is pre-packaged: the asset is already acquired, financing is arranged, and the closing process is defined and fast. Identifying a DST as a second or third property provides a landing place that can actually close inside the window if the primary acquisition fails. The trade-offs of a DST are real and covered in DST fees and risks — but as a backstop against a failed exchange, the comparison is not DST versus direct property; it is DST versus paying tax on the entire gain.
Do not identify property that cannot close in time. An identification of property requiring a lengthy entitlement process, a difficult assemblage, or financing that will not be arranged in time is optionality on paper only.
Watch the value on the 200% rule with margin, and treat the 95% rule as unavailable unless the acquisition of essentially everything identified is near-certain.
Deliver early and confirm receipt. Send the identification days before the deadline and obtain written confirmation from the intermediary. A document sent on day 45 and not received is an identification that did not happen.
Two related points
Property acquired within the 45-day period is generally treated as identified, which is why a taxpayer who closes on replacement property quickly does not have a separate identification concern for that property.
Incidental property — items that would normally transfer with the main asset and are of relatively small value in relation to it — is generally not required to be separately identified. This addresses ordinary fixtures and similar items rather than providing meaningful planning flexibility.
Why the formality matters
The identification rules exist to prevent a taxpayer from keeping options open indefinitely and characterizing whatever they eventually buy as a like-kind exchange. That policy purpose explains the strictness: the rules are designed to force commitment at a point in time, and courts and the IRS have not generally been sympathetic to taxpayers who treated them loosely.
For the taxpayer, the practical translation is that the identification deserves the same attention as the purchase contract. It is a short document, it is easy to prepare correctly, and it is one of the few points in an exchange where a small amount of care produces a large amount of protection.
The deadline mechanics themselves are covered in the 1031 exchange timeline.
This guide is educational and general; it is not tax or legal advice. Identification requirements are technical and fact-specific; work with qualified tax counsel and your qualified intermediary.
Frequently Asked Questions
What are the 1031 identification rules?
Within the 45-day identification period, a taxpayer must identify replacement property under one of three alternatives: the three-property rule, which allows identifying up to three properties regardless of value; the 200% rule, which allows any number of properties whose combined fair market value does not exceed 200% of the relinquished property’s value; or the 95% rule, which allows exceeding both limits provided the taxpayer actually acquires at least 95% of the value identified.
What is the three-property rule?
The most commonly used alternative. A taxpayer may identify up to three properties without regard to their combined value, and may acquire one, two, or all three. Because value is irrelevant under this rule, it provides flexibility for taxpayers who want alternatives without tracking a value ceiling.
How must an identification be made?
In a written document signed by the taxpayer and delivered before the end of the 45-day period to a person involved in the exchange who is not a disqualified person—in practice, the qualified intermediary. The property must be unambiguously described, typically by legal description or street address, and for a fractional interest by specifying the percentage.
Can an identification be changed?
Yes, but only within the 45-day period. A taxpayer may revoke an identification in a signed writing delivered the same way the identification was made, and substitute a different one. After day 45 the identification is fixed.
What happens if you acquire property you did not identify?
Property acquired that was not properly identified generally does not qualify as replacement property, so the value attributable to it is not covered by the exchange and can result in taxable boot. The narrow exception is property acquired within the 45-day period itself, which is treated as identified.
Sources
- Internal Revenue Code Section 1031(a)(3)
- Treasury Regulation Section 1.1031(k)-1(c) (identification of replacement property)
- Revenue Ruling 2004-86 (Delaware statutory trusts and like-kind exchange treatment)
