Open Questions in Section 6418 Practice

1. When exactly does the payment window close?

Status: open

The question. The election requires cash paid within a defined window. Practitioners routinely describe that window as ending on the return due date. The regulation does not say that.

Where the text stops.Treas. Reg. § 1.6418-1(f)(2) defines the window as ending on the due date for completing a transfer election statement, and points to § 1.6418-2(b)(5)(iii), which provides that the statement cannot be completed for any year after the earlier of—

“(A) The filing of the eligible taxpayer’s return for the taxable year for which the specified credit portion is determined…; or (B) The filing of the return of the transferee taxpayer for the year in which the specified credit portion is taken into account.”

The operative words are “the filing of” — an act, not a date. On a plain reading, either party can close the window unilaterally by filing early, and the transferee’s filing can close it on a schedule the transferor never sees. We have not found guidance addressing whether “the filing of” is intended to carry that consequence, or what happens to a signed agreement when it does.

Who could answer. A practitioner who has closed transfers where the two parties had different fiscal years, or who has had this timing question raised on examination.

2. What happens to an installment that lands outside the window?

Status: open

The question. Sellers frequently propose splitting payment across two tax years. Whether that is a partial problem or a total one is not clear from the text.

Where the text stops.Three provisions have to be read together. § 1.6418-1(f)(3) expressly contemplates a forward commitment:

“May include a transferee taxpayer’s contractual commitment to purchase eligible credits with United States dollars in advance of the date a specified credit portion is transferred… if all payments of United States dollars are made in a manner described in paragraph (f)(1) during the time period described in paragraph (f)(2).”

And § 1.6418-2(a)(4)(ii) is categorical:

“No transfer election is allowedif an eligible taxpayer receives any consideration other than cash (as defined in § 1.6418-1(f)) in connection with the transfer.”

Read together, an installment falling outside the window appears not to be “cash” as defined — which, under (a)(4)(ii), reads as invalidating the election entirely rather than reducing it proportionally. We have not found anything that confirms or rejects the all-or-nothing reading. The difference matters enormously: one version costs a seller part of a deal, the other costs the whole thing.

Who could answer. Counsel who has papered a multi-year payment structure under section 6418, or anyone with visibility into how the Service has treated one.

3. Which taxable year does the transferee use, and what does that do to a buyer with a non-calendar year?

Status: open

The question. Buyer qualification lists routinely cover tax appetite, entity type, and credit size. Fiscal year end is rarely on them. It may belong there.

Where the text stops.IRC § 6418(d):

“…shall be taken into account in the first taxable year of the transferee taxpayer ending with, or after, the taxable year of the eligible taxpayer with respect to which the credit was determined.”

For a credit determined in a calendar year 2025 seller year, a buyer whose fiscal year ended in the spring of 2026 has, on this reading, already passed the only year in which it could take that credit into account. Combined with question 1 — the window closing on the earlier filing — a buyer can be structurally ineligible for a given vintage without either party noticing until late in the process. We have not found guidance addressing this interaction directly.

Who could answer. A practitioner who has run a transfer where the buyer had a non-calendar fiscal year.

4. How is an excessive credit transfer actually computed?

Status: open

The question. The consequence of an excessive transfer is severe and falls on the buyer. The computation that produces it is less examined.

Where the text stops.Treas. Reg. § 1.6418-5(a) is explicit about the consequence:

“The tax imposed on the transferee taxpayer… will be increased by… the amount of such excessive credit transfer; and an amount equal to 20 percentof such excessive credit transfer.”

§ 1.6418-5(b) supplies the definition. We have not yet worked through it line by line against a fact pattern, and we have not found a worked example in published guidance showing how the calculation runs where a credit is reduced for reasons that emerge after closing — a basis adjustment, a recharacterized cost, a partial disallowance.

Who could answer. Anyone who has computed one, or defended one.

5. Can reasonable cause reach the 20 percent addition?

Status: open

The question.The 20 percent addition under § 1.6418-5(a) is what makes indemnity caps set at 100 percent of purchase price insufficient — the exposure exceeds what was paid. Whether a reasonable cause defense is available against that addition changes how those caps should be negotiated.

Where the text stops.We have read § 1.6418-5(a) and its statement of the consequence. We have not located a provision addressing reasonable cause specifically as applied to this addition, and we are aware that “we have not found it” is not the same as “it does not exist.” This is stated as an open question precisely because we would rather be corrected than proceed on an assumption.

Who could answer. Tax controversy counsel, or anyone who has seen this raised in an examination.

6. Does section 469(e)(2) reach purchased credits held by a closely held C corporation?

Status: open

The question. Treasury has settled the general question and left a narrower one untouched.

Where the text stops. The preamble to the final regulations is unambiguous that section 469 applies:

“There is no carveout for section 469 in section 6418.”
— T.D. 9993, 89 Fed. Reg. 34,770, 34,783 (Apr. 30, 2024)

And Treasury declined to change that:

“the final regulations do not adopt commenters’ suggestions to not apply the passive credit rules to transferred specified credit portions or to apply the passive credit rules in a different manner than as provided in the proposed regulations.”
— Id. at 34,784

But section 469(e)(2) contains its own relief for closely held C corporations, ending with the sentence:

“A similar rule shall apply in the case of any passive activity credit.”

That sentence is not a carveout from section 469; it is a provision inside it. The preamble does not address it.Whether a closely held C corporation with net active income may apply that relief to a purchased credit is, so far as we can find, unanswered in the published guidance — and it determines whether an entire class of mid-sized buyers is in the market or out of it.

Who could answer. A practitioner who has applied section 469(e)(2) to a purchased credit on a filed return.

7. Which states have not adopted section 6418 at all?

Status: open

The question.Section 6418(b)(2) excludes the proceeds from the seller’s gross income as a matter of federal law. State conformity is a separate question, and sellers usually encounter it after price is agreed.

Where the text stops.Section 6418 was enacted August 16, 2022. A state whose conformity date precedes that has, as a matter of that state’s law, no section 6418 to apply — and falls back to the general rule of section 61. The final transfer regulations were issued in April 2024, which creates a second date a state may or may not have reached.

We do not have a verified state-by-state table, and we are deliberately not publishing one assembled from secondary commentary. Conformity dates move by statute every year, and a table that is wrong is worse than no table. What we would like is a source that is maintained.

Who could answer. State and local tax practitioners; a maintained conformity survey with citations to the state codes.

8. Can a surety bond stand behind a tax indemnity?

Status: open

The question. Tax credit insurance has a minimum premium that makes it uneconomic below a certain deal size. Guaranties are the usual substitute. Surety is occasionally mentioned as a third option, and we have not been able to establish whether it actually works here.

Where the text stops.This is not a section 6418 question — nothing in the statute or regulations speaks to it. It is a question about what a surety will write. A tax indemnity obligation is contingent, potentially long-tailed under the five-year recapture period, and triggered by a determination the obligee does not control. We have not found a surety product described as covering it, and we have not found a clear statement that none exists.

Who could answer. A surety underwriter; counsel who has tried to place one.