Updated July 29, 2026. Quick answer: IRC §1259(c)(1) enumerates exactly four transactions that trigger a constructive sale of an appreciated financial position: a short sale, an offsetting notional principal contract, a futures or forward contract to deliver, and acquiring the property when you already hold the short side. A fifth subparagraph is a catch-all — but it applies only “to the extent prescribed by the Secretary in regulations,” and no regulation under §1259 has ever been issued.
The four, as the statute writes them
| §1259(c)(1) | Transaction |
|---|---|
| (A) | A short sale of the same or substantially identical property |
| (B) | An offsetting notional principal contract on the same or substantially identical property |
| (C) | A futures or forward contract to deliver the same or substantially identical property |
| (D) | Where the appreciated position is itself a short sale or a (B) or (C) contract, acquiring the same or substantially identical property |
| (E) | Any other transaction with substantially the same effect — only to the extent prescribed by the Secretary in regulations |
A precision point that changes outcomes. The statute does not use the phrase “substantially similar” anywhere, though secondary summaries use it constantly. Subparagraphs (A) through (D) say “the same or substantially identical property.” Only the (E) catch-all uses a different and looser formulation, “substantially the same effect.” Identical is a much narrower word than similar, and it is doing real work in every one of the operative triggers.
The fact the marketing leaves out: there is no Treasury regulation under §1259. Section 1259(c)(1) lists four transactions that trigger a constructive sale — a short sale, an offsetting notional principal contract, a futures or forward contract to deliver, and the mirror case of acquiring the property when you are already short. A collar is none of them. The only way to reach one is subparagraph (E), and (E) applies by its own terms only “to the extent prescribed by the Secretary in regulations.” Walking the current eCFR structural index for Title 26 for any node containing “1259” returns nothing: 26 CFR part 1 runs from §1.1258-1 directly into the §1260 rules. Congress in 1997 expressly asked Treasury to set collar standards and said it expected them to apply prospectively. Nearly three decades later they do not exist.
What that means in practice
An instrument either fits one of (A) through (D) or it does not. If it does not, reaching it requires (E), and (E) has no content. That is why the constructive-sale question resolves cleanly for some structures and remains genuinely open for others — not because the analysis is hard, but because half the statute was left for a regulation that never arrived.
Where a transaction does hit a trigger, the position is treated as sold at fair market value on that date — though §1259(c)(3) supplies a narrow escape hatch for transactions closed shortly after year end.
Section 1259 applies to constructive sales occurring after June 8, 1997, subject to the transitional exceptions in the effective-date provision of the Taxpayer Relief Act of 1997. Note what that rule keys on: the date of the transaction, not the vintage of the position. A short sale entered into today against a block bought in the 1990s is a constructive sale occurring after June 8, 1997, and is squarely inside the section. A long-held low-basis position is not grandfathered out of it.
The best-documented application is the prepaid variable forward, which escapes (C) on a definitional point — Rev. Rul. 2003-7 and what it actually requires.
Sources
IRC §1259(c)(1)(A)–(E), §1259(c)(3)(A) and (B), §1259(d)(1) and §1259(f); Pub. L. 105-34 §1001(d) (effective-date note); H.R. Conf. Rep. No. 105-220, at 512 (1997); Rev. Rul. 2003-7, 2003-1 C.B. 363. Absence of any regulation under §1259 verified against the eCFR structural index for Title 26, 2026-07-01 edition. All read July 2026.
This states what the cited authority says. It is not tax or legal advice. Constructive-sale analysis, partnership nonrecognition and insider-trading defences all turn on transaction documents and facts that no page can see, and the instruments described here are executed under contracts whose terms vary by provider.