1031 Exchange Identification Rules: 45‑Day Property Guide

Scope and definition: the 45‑day identification rule (short answer)

Short answer: in a deferred exchange under Internal Revenue Code rules commonly called a 1031 exchange, the exchanger generally has 45 calendar days from the date the original (“relinquished”) property is transferred to identify replacement property(ies) in writing. That written identification must be signed by the exchanger and delivered to the qualified intermediary, the seller of the replacement property, or another party identified by the intermediary as acceptable to receive the identification. Identification follows one of three recognized paths — the three‑property rule, the 200‑percent (200%) rule, or the 95‑percent rule — and identification is measured in calendar days, not business days. This guide explains how those options differ, who typically receives the written notice, what qualifying descriptions look like, how revisions are treated, and what records professionals advise keeping to document the sequence of events. The authoritative IRS Fact Sheet on 1031 exchange identification rules and IRS Publication 544 provide the foundational guidance for these concepts and are cited in the official sources list below.

Applicable facts: who, what, and who receives the identification

The identification window is fact‑sensitive. The 45‑day period begins on the date the relinquished property is transferred out of the exchanger’s control according to the exchange structure in place. That date is the reference point for counting calendar days and for triggering the identification obligation. The taxpayer who held title to the relinquished property at the time of its transfer is generally the person who must make the identification; if title was held by an entity, the entity’s tax classification and ownership facts determine who speaks for the exchange. Because those ownership and title facts influence responsibility for the identification, it is common to involve a qualified intermediary and—separately—tax and legal advisers who understand the exchanger’s ownership structure.

Delivery of the written identification is an essential fact. The IRS guidance makes clear that the written list must be signed and delivered to an appropriate recipient: most commonly the qualified intermediary who is handling the exchange, or the seller (or their agent) of the replacement property. Advisers often recommend documenting acceptance of the identification in writing from the recipient, so there is a clear timestamped record showing the exchanger satisfied the written delivery component within the 45 days. The identification must contain a clear description of each property identified; acceptable descriptions can include unambiguous addresses, legal descriptions, or other description methods that allow a third party to identify the specific real property in question.

The role of the qualified intermediary is procedural: to hold sale proceeds and to receive identification, among other exchange administration tasks. The qualified intermediary is not the exchanger’s tax adviser, and the intermediary’s role does not replace the need for the exchanger to obtain tax advice about selection strategy, basis, or other tax consequences. If title or ownership is complex (for example, transfers involving single‑member entities, partnerships, or other ownership forms), the owner’s tax classification facts influence who signs and delivers the identification and how the exchange documents are prepared.

Sequencing and classification choices: 3‑property, 200‑percent, and 95‑percent paths

When the 45‑day window opens, the exchanger chooses an identification path. The three most commonly described paths are the three‑property rule, the 200‑percent rule, and the 95‑percent rule. Each path is a way to limit exposure to the strict counting rules that define how many replacement properties you may identify and under what circumstances. The three‑property option allows identification of up to three properties regardless of total value; the 200‑percent option allows identification of more than three properties but limits total identified value to 200% of the value of the relinquished property; the 95‑percent option permits identification of any number of properties but requires that the exchanger acquire at least 95% of the aggregate value of the identified properties to meet that path’s condition. These are decision structures, not recommendations; professionals typically review an exchanger’s liquidity, market realities, and fallback choices before choosing a path.

Choosing among the three choices depends on several transaction facts. If market timing suggests only a few practical replacement prospects, the three‑property rule is often the simplest option. If the exchanger is uncertain and wants more optionality while still limiting the scope of the list, the 200‑percent path may be attractive—but it requires careful preliminary valuation work so the identified properties’ combined value does not exceed the 200% threshold relative to the relinquished property. The 95‑percent path can provide maximum flexibility when the exchanger expects to purchase many small parcels; however, successfully using that path typically requires near‑complete execution on the identified properties, because the exchanger will generally need to acquire 95% of the aggregate identified value to be within that path.

Importantly, these classification paths are not interchangeable mid‑course without attention to timing and delivery rules. If the exchanger revises the list, the timing of the revision and the recipients of the revised written identification are facts that influence whether the revision is effective. Practitioners commonly recommend treating any revision as a new written identification event for recordkeeping purposes and obtaining written acknowledgement from the recipient to show the revised list was received within the 45‑day window.

Timing and reporting: calendar days, delivery, and related deadlines

Timing is the central sequence fact for identification. The 45‑day period is measured in calendar days beginning the day after the transfer of the relinquished property; that period includes weekends and holidays. The identification must be made within those 45 calendar days. A related and separate deadline is the overall exchange period within which the replacement property must be received — commonly described in exchange guidance as a 180‑day period measured from the transfer date of the relinquished property or by the due date of the exchanger’s tax return for the year of transfer, whichever rule applies under the controlling provisions. Those two periods operate together: the 45‑day identification requirement is an earlier, shorter window that sets which properties are eligible to be acquired during the overall exchange window.

How the identification is delivered is an important record fact. Delivery methods that create a verifiable timestamp are preferred: certified mail with return receipt, courier with signed delivery receipt, or direct written acknowledgement from the qualified intermediary or the seller are typical examples. Electronic delivery can be effective if the recipient accepts such delivery and provides an electronic acknowledgement that clearly establishes the date and content received. Many qualified intermediaries publish accepted delivery instructions; follow those instructions and keep documentation of the delivery and any confirmations received.

Reporting of the exchange on tax filings normally follows the closing of the exchange and the specific reporting form instructions. The information tracking the identification event — dates, content, and recipient acknowledgements — is not only an internal control; it is the factual sequence professionals will rely on when preparing exchange reporting. Because the 45‑day identification event precedes closing on any identified replacement property, the documentation created during those first 45 days is often central to preparing the later exchange return or report.

Records to gather and preserve for a reliable record package

Maintain a contemporaneous package that documents the chain of events: a dated copy of the written identification, the method of delivery, and the recipient’s acknowledgement. A practical record package typically contains a signed and dated identification list; the delivery receipt or acknowledgement from the qualified intermediary or seller; closing statements for the relinquished property; closing statements for any replacement property acquired; correspondence and emails that show negotiation and acceptance of identified properties; and the exchange agreement with the qualified intermediary that records the exchange structure and the transfer dates. When ownership is held through an entity, include entity formation documents and any trustee or operating agreement excerpts that clarify who had the authority to identify on behalf of the entity.

Include supporting valuation materials when the identification path requires value determinations — for example, when taking the 200‑percent or 95‑percent path. Those materials might include broker quotes, listing histories, appraisal summaries, and other contemporaneous materials that reasonably support the identified values. Keep all communications with the qualified intermediary showing receipt and acceptance of the identification. If the exchanger revises an identification list, keep both versions and the acknowledgements for each; show dates and delivery method for the revisions. Practitioners often keep a simple chronological index that ties each document to the relevant exchange date so the narrative of the exchange is readily reconstructed.

Finally, keep records for as long as other ownership records are retained under ordinary tax document retention guidance. The exchange record package is part of the property’s transactional file and will inform later basis calculations, sale analysis, and any post‑transaction due diligence.

Complexity and next-path selection: when to get advisory help

The identification choice and its execution can be straightforward in simple, single‑property transactions or more complex when the exchanger faces multiple potential replacements, fractional interests, or complex ownership facts. Because identification is a short, fixed window, careful pre‑closing planning helps prevent rushed choices after the relinquished sale closes. Advisers often recommend pre‑limiting a practical set of replacement candidates before closing the relinquished property so that the identification list is ready to be signed and delivered promptly on the transfer date.

The qualified intermediary handles the administrative mechanics of the exchange, but the intermediary typically does not provide tax advice about which identification path best aligns with the exchanger’s tax profile or investment objectives. Advisors who are typically involved at the selection stage include tax counsel, a CPA with exchange experience, and a real estate transactional attorney. When valuation matters—such as when contemplating the 200‑percent path—independent valuation input can reduce the risk of an unintended over‑valuation in the identification package.

When a taxpayer’s ownership includes entities or when several owners or related parties are connected to the transaction, advisers help clarify whether the taxpayer who owned the relinquished property is the taxpayer required to identify. Where multiple properties are acquired as part of a single investment plan, advisers can help structure the identification list so it reflects realistic acquisition possibilities and to document why a given path was selected. If the transaction crosses state lines, local recording or title matters may affect the practical description of a property and how it should be identified in writing.

If you are evaluating your next steps, consider using tools and resources to assess timelines and value ranges. Useful Uncle Kam resources include the 1031 exchange calculator and the general 1031 resource guide; for ownership and basis questions, see the rental property cost basis guide. For broader planning that may involve business exit or investment structuring choices, the Business Exit and Sale Tax Planning hub and the Real Estate Investors service page present additional considerations. If you expect to rely on more specific how‑to or stepped timelines, consult experienced advisers early so that identification choices are made with adequate documentation and in alignment with the exchanger’s broader transaction plan.