Forty-five days from the close of the relinquished property. The clock starts the day after closing and runs continuously — calendar days, not business days, including weekends and holidays — to the end of day on day 45. By midnight on the 45th day, the seller must have submitted written identification of the replacement property or properties to the qualified intermediary (QI) holding the exchange funds. After day 45, identification is final. No additions, no substitutions, no exceptions.
The 45-day identification window is the most operationally unforgiving rule in the 1031 exchange framework. Most failed exchanges fail at this step, almost always because the seller underestimated how compressed 45 days actually feels when running a real replacement search against a real market. The closing of the relinquished property is the loud event; the 45-day deadline is the quiet one that does most of the damage to unprepared sellers.
The IRS requires identification to be in writing, signed by the taxpayer, and delivered to the qualified intermediary or to the seller of the replacement property (not to the taxpayer's own files). Standard practice is to deliver to the QI, who timestamps the identification document.
The identification must describe each property unambiguously. For real estate, this means the legal address or assessor's parcel number — vague descriptions like "a building in Phoenix similar to the one I just sold" do not satisfy the requirement.
Once delivered, the identification can be revoked only if a new identification is delivered within the same 45-day window. After day 45, the identification is locked. The taxpayer can close on any of the identified properties (subject to the 180-day completion deadline) but cannot acquire anything that wasn't identified.
The IRS allows three identification structures, and the taxpayer picks one. Most sellers default to the three-property rule, often without realizing the other options exist.
The three-property rule. Identify up to three replacement properties, regardless of value. The most common structure. Simple, flexible, and accommodates the common pattern of identifying a primary target and one or two backups.
The 200% rule. Identify any number of replacement properties, but the aggregate fair market value of all identified properties cannot exceed 200% of the value of the relinquished property. A seller who sold a $5M building can identify multiple replacements totaling up to $10M in aggregate value. Useful when the seller wants flexibility to mix and match smaller replacement properties.
The 95% rule. Identify any number of replacement properties of any aggregate value, but the taxpayer must actually acquire at least 95% (by value) of the properties identified. The strictest rule and the rarely-used one. Typically applicable only when the seller has a high-conviction list of multiple properties and the operational capacity to close on substantially all of them.
The three-property rule is the right default for most LA multifamily sellers doing standard single-property replacement exchanges. The 200% rule is the right default for sellers using DSTs or fractional structures where multiple identification is the strategy. The 95% rule is rare in practice.
Forty-five days sounds like a long time. It is not.
A real replacement search involves identifying target markets, identifying brokers in those markets, getting on tour, evaluating properties, running underwriting on candidates, performing preliminary due diligence, and reaching a level of conviction sufficient to commit. Doing this from a cold start in 45 days is operationally tight; doing it well is harder than most sellers anticipate.
The sellers who do this best start the replacement search before the relinquished property closes — sometimes 60 to 90 days before. They have brokers engaged in target markets, candidate properties under evaluation, and underwriting frameworks ready to apply. When the relinquished property closes, they have a short list of viable targets and the identification document is largely already drafted. The 45-day window becomes a final selection exercise rather than a search exercise.
The sellers who struggle are the ones who treat the 45 days as the search window. They close, take a week to decompress, spend two weeks building broker relationships, two weeks getting on tour, and find themselves at day 30 without conviction on any property. The remaining 15 days become a forced choice from inadequate options.
When the 45-day window approaches with no clear conviction, three structures preserve the exchange while reducing risk.
Identify Delaware Statutory Trust (DST) backups. A DST identification can be made as one of the three properties under the three-property rule. The DST offering set typically has stable availability across the year, so the DST identification is unlikely to evaporate during the 180-day window. The DST functions as a parachute — if the primary direct-replacement target falls through, the DST closes the exchange and preserves the tax deferral. The cost is the DST's fee load if it actually gets used; the value is the optionality.
Identify the Section 121 backup if applicable. For sellers with a personal residence component, certain structured combinations of 121 (primary residence exclusion) and 1031 are possible. Limited applicability for pure multifamily sellers but worth knowing exists.
Negotiate seller financing on the relinquished property to extend the timeline. If the relinquished property hasn't yet closed and the search is genuinely not converging, structuring the sale with extended close timing can buy weeks. Once the relinquished property has closed, this option is gone.
The exchange fails. The QI returns the proceeds to the seller, and the full gain on the relinquished property becomes taxable in the year of sale. The 1031 deferral is lost, period. There is no extension, no late-identification mechanism, no IRS sympathy.
Federal disaster declarations occasionally produce limited extensions for taxpayers in declared disaster areas — a narrow exception that does not apply to routine deadline slippage. Outside disaster declarations, the deadline is the deadline.
The 45-day identification deadline is the first deadline. The 180-day completion deadline is the second. From the close of the relinquished property, the seller has 180 days (also calendar days, also continuous, also unforgiving) to actually close on one or more of the identified properties.
The 180-day deadline is also strict, but it is operationally easier than the 45-day deadline because by day 45 the universe of possible closings has been frozen. The remaining 135 days are spent moving identified properties through due diligence, financing, and escrow — work that has a more predictable rhythm than search.
The tax-return filing deadline (April 15 or the taxpayer's fiscal year date) can compress the 180-day window. If the relinquished property closed in October, the 180 days runs into April — but the taxpayer's return must be filed (or an extension obtained) before the 180-day window expires, because once the return is filed the exchange is treated as complete as of that date. Extension filing is routine for active 1031 exchanges crossing the year-end.
Start the replacement search before the relinquished property closes. Engage replacement-market brokers 60 to 90 days before listing. Build the candidate list. Run preliminary underwriting on the top three to five candidates. Have the qualified intermediary engaged and the exchange documents drafted before close.
When the relinquished property closes, the 45 days should be a confirmation exercise, not a discovery exercise. The sellers who treat it as a discovery exercise are the ones who end up identifying weaker properties under time pressure or losing the deferral entirely.
The other thing I tell sellers is that the QI is not optional and the QI is not interchangeable. The QI must be engaged before the relinquished property closes — if the seller takes constructive receipt of the sale proceeds, the exchange is dead. Select the QI early, vet them like you would vet a lender, and confirm the exchange documents are in escrow before the closing date arrives.
Forty-five days is enough time to make a confident decision when the work of selecting was done before the clock started. Forty-five days is not enough time to do the work and make the decision. The sellers who run this well treat the 45-day window as a final selection process backed by months of preparation. The sellers who lose the exchange treat the 45 days as the project plan. The IRS is indifferent to which approach the seller took. The taxpayer is not.
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Michael Sterman is Senior Managing Director Investments at Marcus & Millichap, specializing in Los Angeles multifamily transactions.
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