After day 45, can I switch to a different unit or parcel in the same identified building?

A different unit is a different property under the receipt test

The regulation applies its receipt rule "separately to each replacement property" and asks whether what you got is "substantially the same property as identified." Its examples compare the property received with the property identified: a fence added to identified land passes, a barn carved out of an identified farm parcel fails because it differs in basic nature or character from the whole.

None of the examples lets you trade one identified property for a comparable property next door. A condominium unit or a subdivision lot is generally conveyed by its own deed and legal description, so unit 5C is not unit 4B, however similar the floor plan.

Swapping in a property you never named is the subject of changing your identification after day 45, and the answer there is the same: changes end at midnight on day 45.

Naming the building or the project does not cover every unit in it

Paragraph (c)(3) requires that replacement property be "unambiguously described," and the regulation's own failing example is a notice for "unimproved land located in Hood County with a fair market value not to exceed $100,000," which identified nothing. "Any two-bedroom unit at 200 Bay Street" has the same problem.

If you identified the whole building by its address and then buy a single unit, you receive a small fraction of the identified property's value. The only partial purchase the regulation accepts, in Example 4, was land worth 75% of the identified parcel with the same character. One unit in a building of many units is far from that.

For multi-building projects, the same logic applies to buildings and phases: identify the building, pad or lot you will close on, by legal description where one exists.

Worked example: three units named, any one can close

Hypothetical, round numbers. You sell a rental for $600,000 and want a unit in a new condominium tower. Before day 45 you identify unit 4B at $550,000, unit 5C at $560,000 and unit 6A at $580,000, by unit number and building address.

On day 70 the developer tells you 4B has a construction defect. You close on 5C instead. Because 5C was on your list, there is no substitution, and the three-property rule allowed three units of any value.

Had you named only 4B, the only choices would be to close on 4B, fix the problem within it, or let the exchange fail for that property. The 200% rule would not have helped here: four units totalling about $2.2 million exceed twice the $600,000 sale.

• Write unit numbers and the building's legal description or street address exactly as the purchase contract will show them.
• Include parking or storage units you are buying with the unit, or confirm they are incidental under paragraph (c)(5).
• Keep one slot for a backup outside the project if the developer controls all three units.

Units still under construction add a second test

If the unit is being built, paragraph (e) applies. Usual or typical production changes are ignored, but substantial changes mean the property received is not substantially the same as identified.

Only the part of the unit that is real property under local law and completed by the time you receive it counts as like-kind replacement property. Construction finished after you take title is not. See new construction as replacement property.

Use the open slot for something that cannot be sold out from under you

A unit list can fail all at once if the same developer delays all three. A Delaware Statutory Trust interest on the list, described by the trust's name, can serve as the backup; see how to identify a DST interest.

If day 45 has already passed and only one unit is identified, negotiate within that unit: price, closing date, finishes and credits can change without changing the property. Have your intermediary review any contract amendment before you sign.

One timing rule works in your favour. Under paragraph (c)(1), any replacement property you actually receive before the end of the identification period is treated as identified. If a better unit appears on day 30 and can close by day 45, closing it settles the question.