1031 Exchange Mechanics: Identification Rules, Timing, and Like-Kind Requirements

Key Takeaways

How the Clock Works

A 1031 exchange imposes two concurrent deadlines that begin running on the date the relinquished property closes, as codified in IRC Section 1031(a)(3) and detailed in Treasury Regulation 1.1031(k)-1(b). Not the date you sign the PSA, not the date the buyer goes hard on their deposit. The date the deed transfers and proceeds flow to the qualified intermediary. From that moment, two clocks run simultaneously:

• Day 45: Identification deadline. The exchanger must identify potential replacement properties to the person obligated to transfer the replacement property (even if that person is a disqualified person) or to another person involved in the exchange other than the exchanger or a disqualified person, such as the QI. The identification must be in writing, signed by the taxpayer, and hand delivered, mailed, faxed, or otherwise sent before midnight on the 45th calendar day (best practice: confirm receipt). Calendar days, not business days. Because the period ends "at midnight on the 45th day thereafter" (Treasury Regulation 1.1031(k)-1(b)(2)(i)) and the IRS states that the limits cannot be extended for any circumstance or hardship except in the case of presidentially declared disasters, plan to identify by the last business day on or before day 45 rather than relying on a weekend rollover.
• Day 180: Closing deadline. The exchanger must close on the replacement property by midnight on the 180th calendar day. This clock runs concurrently with the 45-day window, meaning the exchanger has 135 days after identification to close, not 180.

Both deadlines are absolute. There is no extension mechanism, no force majeure carve-out, no court petition process. The only relief comes through IRS postponements of time-sensitive acts under sections 7508A (federally declared disasters and terroristic or military actions) and 7508 (combat-zone service). Rev. Proc. 2018-58 lists the 45-day and 180-day periods among the postponable acts, and Notice 2020-23 used section 7508A to postpone specified time-sensitive actions due on or after April 1, 2020, and before July 15, 2020, to July 15, 2020. Outside of those narrow exceptions, a missed deadline collapses the entire exchange into a taxable sale.

Consider an institutional portfolio manager disposing of a $40M office building with a $12M adjusted basis, or $28M of embedded gain. For illustration, assume $10M of that gain reflects accumulated straight-line depreciation. UnderIRC Section 1(h)(1)(E) and 1(h)(6), that $10M is unrecaptured Section 1250 gain taxed at a maximum of 25%, or $2.5M. The remaining $18M is taxed at 20%, or $3.6M. The 3.8% net investment income tax underIRC Section 1411adds about $1.06M on the full $28M where it applies. For individual owners, holding directly or through a partnership, missing the 45-day window therefore means roughly $7.2M of federal tax, before state tax. (Section 1(h) rates and the NIIT do not apply to a C corporation, which pays its corporate rate instead.) The stakes justify the diligence.

Like-Kind After TCJA

The Tax Cuts and Jobs Act of 2017 (Public Law 115-97, Section 13303) narrowed Section 1031 to real property only, effective for exchanges completed after December 31, 2017 (with a transition rule for exchanges already under way on that date). Before TCJA, taxpayers could exchange personal property (aircraft, equipment, art) under 1031. That's gone. The only qualifying asset class is real property, which, for CRE practitioners, means the statute now applies exclusively to the asset class they care about.

The "like-kind" standard for real property remains broad. An office building is like-kind to a warehouse. A ground leasehold with 30 or more years to run is like-kind to a fee simple interest, including unimproved land, under Treasury Regulation 1.1031(a)-1(c). The IRS confirmed in final regulations (T.D. 9935, published in the Federal Register on December 2, 2020) that real property includes:

• Land and improvements: buildings, inherently permanent structures, structural components
• Unsevered natural products: growing crops, timber, minerals in place
• Water and air space superjacent to land: for example, boat-slip water space at a marina, or air space above a parcel
• Intangible interests in real property: leaseholds, options to acquire real property, easements (Treas. Reg. 1.1031(a)-3(a)(5) sets no minimum lease term; the 30-year threshold matters only for whether a leasehold is like-kind to a fee interest)

Critically, the final regulations also clarify what does not qualify: tangible property that is not an inherently permanent structure, a structural component, or real property under state or local law (for example, movable equipment and furniture), and a license or permit to engage in or operate a business on real property. Affixed machinery and equipment is real property if it meets the inherently-permanent-structure or structural-component test (Treas. Reg. 1.1031(a)-3(a)(2)). Separately, under IRC Section 1031(h), real property located in the United States and real property located outside the United States are not property of a like kind, so domestic property must be exchanged for domestic property and foreign property for foreign property. Because Section 1031(a)(1) is limited to real property, personal property of any kind, including goodwill and going-concern value, is outside Section 1031 after TCJA (the pre-TCJA like-kind rule for goodwill is in Treasury Regulation 1.1031(a)-2(c)(2)).

Cost segregation interacts with this definition, but not the way it is often described. The real property definition in Treasury Regulation 1.1031(a)-3 applies only for Section 1031, and the regulation states that no inference is intended for depreciation or for Sections 1245 and 1250. A component that a cost segregation study places in a 5-year or 7-year MACRS class can still be real property for 1031 purposes if it is a structural component or part of an inherently permanent structure. As The Tax Adviser concluded after T.D. 9935, nearly all building components identified as 5- and 7-year property are real property under Section 1031.

The real exposure is depreciation recapture. Those components remain Section 1245 property for recapture purposes. Under IRC Section 1245(b)(4), Section 1245 gain in a like-kind exchange is capped at the gain recognized plus the fair market value of non-1245 property acquired. In practice, the recapture is deferred only if the replacement property carries enough Section 1245 property to absorb it. Exchange a heavily cost-segregated building for one with little 1245 content and the recapture comes out as ordinary income even though the exchange otherwise qualifies. Genuinely movable personal property, such as furniture or removable equipment, is not real property and is taxable as other property, although under Treasury Regulation 1.1031(k)-1(g)(7)(iii) incidental personal property worth no more than 15% of the replacement real property does not break the qualified intermediary safe harbor.

Section 1031 was preserved fully intact under the One Big Beautiful Bill Act signed July 4, 2025. The Biden-era proposals (Treasury's FY2022 Green Book) to cap deferred gains at $500,000 per taxpayer per year ($1 million for married individuals filing jointly) never passed. A 2021 Ernst & Young study, commissioned by a coalition that included ADISA and the Institute for Portfolio Alternatives, estimated that like-kind exchanges support approximately 568,000 jobs and contribute $55.3 billion to U.S. GDP.

The Three Identification Rules

Within the 45-day window, the exchanger must identify potential replacement properties under one of three rules established in Treasury Regulation 1.1031(k)-1(c). The identification must be in writing, signed, and sent to a non-disqualified party (typically the QI). Each rule imposes a different constraint on the number and value of properties that can be identified.

Table 1. The three identification rules. Each trades flexibility for risk. The three-property rule is the safest; the 95% exception is the most flexible but requires closing on nearly everything identified.

Three-Property Rule

The exchanger may identify up to three properties regardless of their aggregate fair market value. It is the simplest rule and carries the least compliance risk. If you sell a $25M industrial building and identify three potential replacements (a $30M warehouse, a $22M distribution center, and a $28M flex property), all three qualify regardless of total value ($80M, or 320% of the relinquished property).

The constraint is quantity, not value. Three means three. Identify a fourth property without satisfying the 200% rule or the 95% exception, and you are treated as having identified nothing, apart from any replacement property already received by day 45. The exchange fails and the full gain is taxable. There is no "pick your best three" correction after day 45.

200% Rule

The exchanger may identify any number of properties as long as their aggregate fair market value does not exceed 200% of the relinquished property's FMV on the date of transfer. Sold a $25M building? You can identify $50M worth of replacement properties, which could be five properties at $10M each, or ten at $5M each, or any other combination.

The 200% rule is useful when the acquisitions team has multiple targets in the pipeline but isn't sure which will close. It provides more optionality than the three-property rule but still imposes a hard cap on aggregate value.

95% Exception

If the exchanger identifies properties exceeding the 200% threshold, the exchange can still qualify under the 95% exception, but only if the exchanger acquires at least 95% of the aggregate identified FMV by the 180-day deadline. This is a high-risk strategy: identify $100M of replacement properties, and you must close on at least $95M of them.

Institutional portfolio managers sometimes use the 95% exception deliberately during large multi-property dispositions. When disposing of a $200M portfolio across 8 properties, each generating a separate exchange, the team may need to identify a large pool of replacement targets. The 95% exception provides the flexibility, at the cost of an almost-certain obligation to close on nearly everything identified.

Multi-Asset Identification Strategy

When an institutional fund disposes of a portfolio (say, five properties generating $120M in aggregate proceeds across five separate exchanges), the identification challenge compounds. Each exchange has its own 45-day clock, its own identification, and its own closing deadline. The clocks may start on different dates if the portfolio properties close sequentially.

The simplest approach is to use the three-property rule for each exchange independently. Five exchanges means fifteen identification slots. But the acquisitions team typically has a smaller universe of viable targets: perhaps eight or nine properties that match the fund's investment criteria, geography, and return thresholds. The same replacement property can be identified in multiple exchanges, which creates concentration risk. A target that falls through does not invalidate the identifications that listed it, since an identification is tested as of day 45. But every exchange that counted on that target loses its best option at the same time and must close on something else it identified. Exchanges relying on the 95% exception are the exception: missing one property can drop them below the 95% threshold and fail them outright.

Coordinating sequential closings

Portfolio dispositions rarely close simultaneously. A buyer may close on three properties in June and two in August, creating staggered 45-day windows. The identification strategy must account for this overlap. Properties identified in the June exchanges may already be under contract by the time the August identification deadline arrives, or they may have fallen out of escrow, requiring the team to find new targets on a compressed timeline.

The DST backstop

Some institutional exchangers identify a Delaware Statutory Trust (DST) interest as one of their three properties under the three-property rule. The DST serves as a backstop: a replacement property of last resort if the primary targets fall through after the 45-day deadline, when the identification can no longer change. DSTs are pre-packaged, securitized real estate interests that can be identified and closed quickly, absorbing the exchange proceeds and preserving the tax deferral even when the preferred direct acquisition doesn't materialize.

This strategy has a cost: DST interests carry upfront load and structuring costs, limited upside, and no operational control. But for an individual owner, a failed exchange on a $30M gain triggers roughly $7.1M to $8.6M of federal tax, at 23.8% if none of the gain is unrecaptured Section 1250 gain and 28.8% if all of it is. Against that, the DST backstop is a rational insurance policy.

Late-Year Filing Deadline Compression

The 180-day closing deadline has an often-overlooked interaction with the federal income tax filing deadline. Under IRC §1031(a)(3)(B), the exchange must be completed by the earlier of:

1. 180 calendar days after the transfer of the relinquished property (§1031(a)(3)(B)(i)), or
2. The due date (including extensions) of the taxpayer's federal income tax return for the taxable year in which the relinquished property was transferred (§1031(a)(3)(B)(ii)).

The due date depends on the entity. Under IRC Section 6072, calendar-year partnerships and S corporations file by March 15, while calendar-year C corporations (including REITs) and individuals file by April 15. If a partnership sells a property on October 15, its 180-day window extends to April 13 of the following year (assuming a non-leap following year), but without an extension its return is due March 15, and the exchange must be completed by then. A C corporation selling on the same date is not affected, because April 15 falls after day 180. For calendar-year partnerships and S corporations, the trap starts with closings after September 16 (September 17 if the following year is a leap year). For C corporations and individuals, it starts with closings after October 17 (October 18 if the following year is a leap year). These cutoffs assume March 15 and April 15 are not moved by a weekend or legal holiday; under IRC Section 7503, a due date that falls on a Saturday, Sunday, or legal holiday moves to the next day that is not, which shifts the cutoff by the same number of days.

The practical solution is straightforward: file an extension. Partnerships and corporations file Form 7004, which gives an automatic extension of generally 6 months, so a partnership's March 15 deadline moves to September 15. Individuals file Form 4868. With the extension, day 180 falls before the extended due date, so the 180-day window becomes the binding constraint. Every institutional tax advisor handling a late-year disposition should put the extension on the exchange calendar at closing and confirm it is filed before the original due date.

Common Mistakes

Each of the following failure modes can collapse an exchange and trigger the full tax liability:

• Ambiguous property descriptions. The identification must unambiguously describe the replacement property, which for real property generally means a legal description, street address, or distinguishable name. "An industrial building in Dallas" does not meet that standard. For properties under construction, the identification must include both the legal description of the land and a description of the improvements to be constructed. An identification letter that describes a portfolio by fund name rather than by individual property addresses risks failing this test.
• Delivering identification to a disqualified person. The identification must be delivered to the QI, the seller of the replacement property, or another person involved in the exchange, but not to the exchanger's agent (attorney, accountant, broker, or employee within the preceding two years). Sending the identification letter to your own attorney instead of the QI is an error that invalidates the identification.
• Assuming you can revoke and re-identify after day 45. The exchanger may revoke an identification and substitute a new one, but only within the 45-day window. After midnight on day 45, the identification is locked. No amendment, no correction, no substitution. If your preferred replacement property falls through on day 50, you are limited to whatever else you identified before the deadline.
• Ignoring the concurrent clock. The 180-day deadline runs from the closing date of the relinquished property, not from the end of the 45-day identification window. Practitioners who treat the 180 days as a sequential period after identification are miscounting. They actually have 135 days after identification to close.
• Constructive receipt of proceeds. If exchange proceeds are deposited into an account that the exchanger can access, pledge, borrow against, or otherwise control, the IRS treats the exchanger as having received the funds under the constructive receipt doctrine outlined in Treasury Regulation 1.1031(k)-1(f) and (g), and the exchange is taxable. All proceeds must flow through the QI and remain outside the exchanger's control until the replacement property closes. The Federation of Exchange Accommodators (FEA) publishes best-practice standards for QI escrow procedures to prevent inadvertent constructive receipt.
• Failing to match the vesting entity. The taxpayer who sells the relinquished property must be the same taxpayer who acquires the replacement property. If a partnership sells the relinquished property, the same partnership must acquire the replacement. The test is the tax owner: selling through one entity and attempting to acquire through an affiliated entity that is a separate taxpayer breaks the exchange. Unless it has elected to be classified as a corporation, a single-member LLC wholly owned by the exchanger is disregarded for federal tax purposes (Treasury Regulation 301.7701-3(b)(1)(ii)), so its activities are treated as those of the owner (Treasury Regulation 301.7701-2(a)) and it can take title to the replacement property.
• Not filing the extension for late-year (after mid-September) closings. As discussed above, the tax return filing deadline can truncate the 180-day window. The risk is highest when the disposition team and the tax team don't coordinate early enough.

How to Model It

A properly structured 1031 exchange model isn't a single spreadsheet. It's a tracking framework that coordinates identification, timing, and tax impact across potentially multiple concurrent exchanges. Here's what it needs:

Exchange timeline tracker

For each exchange: relinquished property close date, day-45 identification deadline, day-180 closing deadline, tax return filing deadline (with and without extension), and the binding deadline (the earlier of day 180 and the return due date, including extensions). This should flag any exchanges where the return due date is binding. Those need immediate attention from the tax team.

Identification matrix

A cross-reference of exchanges and identified replacement properties. Each exchange gets a row; each potential replacement gets a column. The matrix shows which properties are identified in which exchanges, the aggregate value of identified properties per exchange, and whether the identification complies with the three-property rule, 200% rule, or requires the 95% exception. Color-code exchanges that depend on the same replacement property. If that target falls through, the matrix reveals which exchanges are exposed.

Tax impact projection

For each exchange: the adjusted basis of the relinquished property, the realized gain, the projected deferred gain (assuming a full exchange), the projected boot (if the replacement property value or debt doesn't fully match), and the resulting tax liability under various scenarios: full deferral, partial exchange with boot, and complete failure (taxable sale). This lets the portfolio manager quantify the downside of each potential failure point.

Related Articles

This article is part of the 1031 exchange series. Each article covers a specific aspect of exchange structuring for institutional CRE portfolios:

• Boot and Basis Modeling: Cash boot, mortgage boot, carryover basis, and how to model the tax impact in a disposition waterfall.
• Reverse Exchanges: EAT/QEAA structures, Rev. Proc. 2000-37 safe harbor, and improvement exchanges at institutional scale.
• DST Replacement Property: When and how to use DST interests as identification backstops and passive replacement vehicles.
• 721 Exchange / UPREIT: Contributing exchanged property into a REIT operating partnership for liquidity and diversification.