Opinion for the court filed by Circuit Judge TATEL.
The Commissioner of Internal Revenue and Intermountain Insurance Service of Vail disagree about Intermountain’s 1999 gross income to the tune of approximately $2 million, a disagreement arising from Intermountain’s sale of assets and centering primarily on the Commissioner’s conclusion that Intermountain inflated its basis in those assets. But deciding whether Intermountain inflated its basis must wait for another day because we must first answer an antecedent question: did the Commissioner wait, too long to adjust Intermountain’s gross income? Although the Commissioner usually must make such an adjustment within three years, sections 6501(e)(1)(A) and 6229(c)(2) of the Internal Revenue Code give the Commissioner up to six years if the taxpayer (or partnership) “omits from gross income an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in the return.” (emphasis added). Because in this case the Commissioner waited nearly six years after Inter-mountain filed its 1999 tax return, the adjustment was timely only if a basis overstatement can result in an “omission from gross income” for purposes of these two provisions. Id. Believing it does not, the Tax Court granted summary judgment to Intermountain. For the reasons set forth in this opinion, we reverse.
I.
The key tax concept at issue in this case is “basis.” Basis refers to a taxpayer’s capital stake in an item of property — generally the amount the taxpayer paid to obtain it, as adjusted by various other factors. 26 U.S.C. § 1012. When a taxpayer sells property, he realizes gain from that sale, and that gain contributes to gross income. Id. § 61(a)(3). But the taxpayer’s gain from the property sale is not the sale price (or in technical terms, the “amount realized”) but rather the sale price minus basis. Id. § 1001. Given the role basis plays in calculating gross income, a higher basis translates into a lower gross income. In the real world, of course, people generally prefer a higher gross income. But when dealing with the tax collector, lower gross income means a smaller tax bill. Taxpayers, therefore, prefer a higher basis.
The question this case presents is whether a taxpayer who overstates basis in sold property and therefore understates gross income triggers the extended statute of limitations periods. (For the sake of brevity, we will sometimes refer to the issue as whether a basis overstatement constitutes an omission from gross income under the relevant provisions.) This issue “arises in the context of the now infamous Son of BOSS tax shelter,” which shields income from taxation by artificially inflating basis. Appellant’s Br. 4 (internal quotation marks and citations omitted). As amicus Bausch
&
Lomb accurately observes, however, our resolution of this case will “apply equally to
all
taxpayers ... without regard to the nature of the underlying transaction.” Amicus’s Br. 7;
see also Wilmington Partners v. Comm’r,
No. 10-4183 (2d Cir. filed Oct. 13, 2010). Conscious of that, and because we agree with
*695
the Tax Court that “[t]he details of the transactions are largely irrelevant to the issues we face today,” we shall refer to those details only to the extent necessary to explain our disposition of this case.
Intermountain Ins. Serv. of Vail, L.L.C. v. Comm’r,
The Commissioner accuses Intermountain Insurance Service of Vail of using a Son of BOSS tax shelter to avoid taxes on approximately $2 million of income. Inter-mountain realized that income on August 1, 1999 when it sold its assets for $1,918,844. On its 1999 Tax Return, filed on September 15, 2000, Intermountain reported a loss from this sale of $11,420, an amount it calculated by subtracting its purported basis in the sold assets ($2,061,-808) from the sale proceeds ($1,918,844) and the recaptured depreciation ($131,544). Believing Intermountain had artificially inflated its basis in those assets, thus converting a substantial gain into a loss, the IRS mailed Intermountain a Final Partnership Administrative' Adjustment (abbreviated FPAA and pronounced “F-Paw” in tax-speak) on September 14, 2006, nearly six years after Intermountain had filed its 1999 Tax Return. The FPAA concluded that certain Intermountain transactions “were a sham, lacked economic substance and ... had a principal purpose of ... [reducing] substantially the present value of ... [Intermountain’s] partners’ aggregate federal tax liability.” Id. at 4 (quoting the FPAA) (alterations in the original). As a result, the FPAA adjusted Inter-mountain’s basis to $0.
Intermountain petitioned the Tax Court and moved for summary judgment, arguing that the FPAA was untimely because the IRS mailed it after the expiration of the standard three year statute of limitations provided for in 26 U.S.C. §§ 6501(a) and 6229(a) (2000). Insisting that the FPAA was in fact timely, the Commissioner contended that Intermountain’s return triggered the extended six year limitations period, available in the case of any taxpayer, 26 U.S.C. § 6501(e)(1)(A) (2000), or any partnership, 26 U.S.C. § 6229(c)(2) (2000), who
“omits from gross income
an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in the return.” (emphasis added). The alleged omissions to which the Commissioner pointed were almost all overstatements of basis. The key question for the Tax Court, then, was whether such overstatements qualify as omissions from gross income under sections 6501(e)(1)(A) and 6229(c)(2) and thus trigger the six year limitations period. Contending they do not, Intermountain relied on an earlier tax court decision,
Bakersfield Energy Partners v. Commissioner,
Shortly after the Tax Court’s grant of summary judgment — and implicitly contradicting that decision — the Internal Revenue Service issued temporary regulations that interpret the phrase “omits from
*696
gross income” in sections 6501(e)(1)(A) and 6229(c)(2) to include basis overstatements outside the trade or business context. 26 C.F.R. §§ 301.6501(e)-lT; 301.6229(c)(2)-1T (2010). The Service reasoned that because I.R.C. section 61(a)’s standard definition of “gross income” includes “gains derived from dealings in property,” 26 U.S.C. § 61(a)(3), and because such gains are ordinarily calculated by subtracting basis from the amount realized,
id.
§ 1001, “outside the context of a trade or business, any basis overstatement that leads to an understatement of gross income under section 61(a) constitutes an omission from gross income for purposes of sections 6501(e)(1)(A) and 6229(c)(2).” Definition of Omission from Gross Income, T.D. 9466, 74 Fed.Reg. 49,321, 49,321 (Sept. 28, 2009). As for
Colony,
the Service concluded that it applies only to section 6501(e)(l)(A)’s predecessor, pointing out that Congress had enacted section 6501(e)(1)(A) four years
before
the Supreme Court decided
Colony
and had, at that time, added an amendment (limited to the trade or business context) designed to address the very same issue later addressed in
Colony. Id.
Relying on those temporary regulations, the Commissioner moved the Tax Court for reconsideration and to vacate its grant of summary judgment. Denying that motion, the Tax Court found the temporary regulations inapplicable to Intermountain because the standard three year statute of limitations had expired prior to September 24, 2009, the temporary regulations’ applicability date.
Intermountain II,
The Commissioner has appealed the Tax Court decisions in both cases, and because they raise many of the same issues, we scheduled oral argument for both on the same day before the same panel. Although formally resolving only Intermountain’s case here, we also address UTAM’s arguments about whether a basis overstatement constitutes an omission from gross income. In a separate opinion also released today, we address issues unique to that case.
UTAM, Ltd. v. Comm’r,
II.
Determining whether basis overstatements constitute omissions from gross income and thus trigger the extended statute of limitations has long provoked debate, the history of which is critical to understanding this case. Congress first established the applicable extended statute of limitations in 1934 when it added section 275(c) to the tax code. See Revenue Act of 1934, ch. 277, 48 Stat. 680, 745, § 275(c) (codified at 26 U.S.C. § 275(c) (1934)). Section 275(c) lengthened the standard three year period, 26 U.S.C. § 275(a) (1934), to five years for omissions from gross income, providing as follows:
Omission from gross income If the taxpayer omits from gross income an amount properly includible therein which is in excess of 25 per centum of the amount of gross income stated in the return, the tax may be assessed, or a proceeding in court for the collection of such tax may be begun without assessment, at any time within 5 years after the return was filed.
Id.
*697
In the 1940s and 1950s, the courts of appeals divided over how to interpret section 275(c). The Sixth Circuit held that a basis overstatement qualifies as an omission from gross income, thus triggering the extended period.
See, e.g., Reis v. Comm’r,
One year after Uptegrove Lumber, in 1954, Congress, apparently responding to the circuit split, added two new subsections to section 275(c) as part of a major recodification of the 1939 tax code. Internal Revenue Code of 1954, 68 Stat. 730, Pub.L. 83-591 (Aug. 16, 1954). In doing so, Congress also renumbered section 275 as section 6501. Id. The amended text (as relevant to this case) reads:
Omission from gross income....
If the taxpayer omits from gross income an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in the return, the tax may be assessed, or a proceeding in court for the collection of such tax may be begun without assessment, at any time within 6 years after the return was filed. For the purposes of this subparagraph—
(i) In the case of a trade or business, the term “gross income” means the total of the amounts received or accrued from the sale of goods or services (if such amounts are required to be shown on the return) prior to diminution by the cost of such sales or services; and
(ii) In determining the amount omitted from gross income, there shall not be taken into account any amount which is omitted from gross income stated in the return if such amount is disclosed in the return, or in a statement attached to the return, in a manner adequate to apprise the Secretary of the nature and amount of such item.
26 U.S.C. § 6501(e)(1)(A) (1954). Notably, new subsection (i) substantially tracks Uptegrove Lumber’s holding by excluding basis overstatements from the category of omissions from gross income. The amendment, however, used a different mechanism to achieve that result. The Third Circuit had interpreted the phrase “omits from gross income” to exclude basis overstatements, but Congress literally took basis out of section 6501(e)(l)(A)’s equation, redefining “gross income” to mean gross receipts rather than gross receipts minus the cost of goods sold. One other difference is particularly important. Although Uptegrove Lumber involved a manufacturing corporation, its reasoning is not limited to that context. By contrast, and of critical significance to this case, subsection (i) applies only “[i]n the case of a trade or business.” Finally, section 6501(e)(1)(A) lengthened the extended statute of limitations from five to six years.
In a letter to the Senate Finance Committee, attorneys supporting the Third Circuit’s approach stated their “belie[f] that subjection] (i) ... w[as] proposed to *698 reflect the rule of reason announced by cases like Uptegrove Lumber Company v. Commissioner.” An Act to Revise the Internal Revenue Laws of the United States: Hearing on H.R. 8300 Before the S. Comm, on Finance, 83d Cong. 984-85 (1954) (letter from Harry N. Wyatt, D’Ancona, Pflaum, Wyatt & Riskind) (added to the hearing record at the direction of the Committee Chairman, id. at 961) (“Wyatt Letter”). Worried that the new provisions would not apply to, open tax years governed by the pre-1954 tax code, they asked the Committee to make the new subsections retroactive and to indicate that the amendments merely clarified section 275(c). Id. But to no avail — the House and Senate Reports characterized subsections (i) and (ii) as “changes from existing law,” and Congress nowhere indicated that section 6501(e)(1)(A) would apply retroactively. H.R.Rep. No. 83-1337, at 503 (1954), reprinted m'1954 U.S.C.C.A.N. 4017, 4562; S.Rep. No. 83-1622, at 558 (1954), reprinted in 1954 U.S.C.C.A.N. 4621, 5233.
Left unresolved, therefore, was which interpretation — the Third Circuit’s or the Sixth Circuit and the Tax Court’s — applied to section 275(c) of the 1939 Code. Over the next several years, other circuits embraced the Third Circuit’s approach, but the Sixth Circuit stuck with its earlier rule.
Compare, e.g., Davis v. Hightower,
Starting with section 275(e)’s text, the Supreme Court explained that “[a]lthough we are inclined to think that the statute on its face lends itself more plausibly to the taxpayer’s interpretation” — i.e., that basis overstatements are not omissions from gross income — “it cannot be said that the language is unambiguous.”
Colony, Inc.,
Colony
thus closed the first round in the debate over whether a basis overstatement counts as an omission from gross income, that question having been “resolved for the future” (at least in the
*699
trade or business context) by Congress when it enacted section 6501(e)(1)(A) and “for earlier taxable years” (seemingly for all taxpayers) by
Colony
itself.
Id.
at 32,
Substantial omission of income. — If any partnership omits from gross income an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in its return, subsection (a) shall be applied by substituting ‘6 years’ for ‘3 years’.
26 U.S.C. § 6229(c)(2) (1982). At oral argument, Intermountain argued that “this case is not about [section] 6501” but only section 6229 given the Tax Court’s observation that where, as here, the Commissioner has adjusted only partnership items, only section 6229(c)(2) applies. Oral Arg. Tr. 15:13-16:01; see
Intermountain II,
All of this brings us nearly to the present. The latest round in the debate over whether a basis overstatement constitutes an omission from gross income has arisen in the last several years, largely in the context of entities, such as Intermountain, that the Commissioner believes took advantage of Son of BOSS tax shelters.
See, e.g., Bakersfield Energy Partners v. Comm’r,
In several such cases, including this one, the Tax Court concluded that
Colony
controls this latest debate.
See Intermountain I,
Disagreeing with those circuits, the Commissioner issued the temporary regulations, described supra at 695-96, that interpreted sections 6501(e)(1)(A) and 6229(c)(2) to mean that outside the trade or business context an overstatement of basis constitutes an omission from gross income, thus triggering the extended six year statute of limitations. Simultaneously, the Commissioner issued proposed final regulations identical to the temporary regulations. Notice of Proposed Rulemaking, Definition of Omission from Gross Income, 74 Fed.Reg. 49,354 (Sept. 28, 2009). Approximately a year later, and after soliciting comments, the Commissioner withdrew the temporary regulations and replaced them with largely identical final regulations. See 26 C.F.R. §§ 301.6501(e)-l; 301.6229(e)(2)-l; see also Definition of Omission from Gross Income, T.D. 9511, 75 Fed.Reg. 78,897 (Dec. 17, 2010). The Commissioner now contends that these regulations are entitled to Chevron deference and so control the question in this case.
Since the Commissioner issued the final regulations, several of our sister circuits have weighed in on the basis overstatement debate. The Fourth and Fifth Circuits have now joined the Ninth and Federal Circuits in holding that
Colony’s
interpretation of section 275(c) applies to sections 6501(e)(1)(A) and 6229(c)(2).
See Home Concrete & Supply, L.L.C. v. United States,
In addition, in 2010 Congress amended sections 6501(e)(1)(A) and 6229(c)(2). See Hiring Incentives to Restore Employment Act, Pub.L. No. 111-147, 124 Stat. 71, 112. In this opinion, we interpret the version of those sections applicable to 1999, the tax year at issue in this case. See 26 U.S.C. §§ 6501(e)(1)(A), 6229(c)(2) (2000).
III.
As the Supreme Court just recently made clear, courts assessing Treasury
*701
regulations that interpret the tax code, as we do here, must apply the two-step framework of
Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc.,
Although we ordinarily begin a
Chevron
step one inquiry with the statute’s text, given the peculiar circumstances of this case, we must first assess
Colony’s
relevance to the question presented. Indeed, Intermountain’s argument largely “starts and ends” with
Colony.
Oral Arg. Tr. 15:07-15:08. Because “[a]t new [section] 6501(e)(1)(A) Congress adopted the exact same language the Supreme Court interpreted in
Colony,”
Intermountain claims we need do nothing more than apply
Colony’s
holding to this case. Appellees’ Br. 39. Intermountain is, of course, correct that in 1954 Congress transferred essentially all of section 275(c)’s text into section 6501(e)(1)(A), and then added two new subsections. Had the meaning of the transferred text been well-established — either because the text itself was unambiguous or because, although it was ambiguous, the courts and Treasury had consistently interpreted it — then we would agree with Intermountain that this case is easy. We would simply assume Congress intended the text to convey that established pre-reenactment meaning.
See Davis v. United States,
But we face a far different set of circumstances because the language Congress borrowed from section 275(c) was not only understood to be ambiguous,
see, e.g., Uptegrove Lumber, 204 F.2d
at 571 (noting “real ambiguity” in section 275(c)’s text), but had been interpreted one way by the Sixth Circuit and another by the Third.
Compare Reis,
Significantly, the Court concluded that the one source of continuity between section 275(c) and section 6501(e)(1)(A) — the statutes’ essentially identical text — was indeterminate. After all, the Court explained, “it
cannot
be said that the language [of section 275(c) ] is unambiguous.”
See Colony,
Nor do the Court’s few references to section 6501(e)(1)(A) suggest it actually considered that provision’s potentially distinctive meaning. Indeed, the Court first mentioned the new statute in order to explain that although the question presented had been “resolved for the future by [section] 6501(e)(1)(A) of the Internal Revenue Code of 1954,” it had nonetheless granted certiorari because that question remained unresolved “for earlier taxable years” still governed by section 275(c).
Colony,
Intermountain’s sole argument to the contrary focuses on
Colony’s
only other reference to section 6501(e)(1)(A), in which the Court “observe[d] that the conclusion we reach [about the meaning of section 275(c) ] is in harmony with the unambiguous language of [section] 6501(e)(1)(A) of the Internal Revenue Code of 1954.”
Id.
at 37,
The problem with Intermountain’s reading is that it makes this passage incomprehensible. In that passage, the Court called section 6501(e)(l)(A)’s text “unambiguous,” even though earlier in the opinion it had characterized section 275(c)’s text as ambiguous. See
Colony,
In sum, to the extent the Court in
Colony
referred to section 6501(e)(1)(A), it did so only to acknowledge that it was interpreting section 275(c) consistently with the new subsection (i) that Congress had added in 1954 to address the same issue prospectively in the trade or business context. Because that observation does not directly control the question presented here, and because it otherwise seems clear to us that the Court in
Colony
dealt
only
with the limited task of interpreting section 275(c) of the 1939 code for cases arising under that code, we believe the Court left unresolved the issue now before us — namely, how to interpret section 6501(e)(l)(A)’s “omits from gross income” language in cases that fall beyond subsection (i)’s scope. It is to that question that we now turn, keeping in mind that we may only reject the Commissioner’s interpretation at
*704
Chevron
step one if Congress has unambiguously foreclosed it.
Vill. of Barring-ton,
Focusing first on section 6501(e)(l)(A)’s relevant text — “omits from gross income an amount properly includible therein which is in excess of 25 percent of the amount of gross income stated in the return” — we are, though not technically bound by
Colony, see supra
701-04, nonetheless inclined to agree with the Supreme Court’s judgment that this text, even read in isolation, is susceptible to both the Commissioner’s and Intermountain’s interpretations.
Colony,
Resisting that conclusion, Intermountain points out that “gross income” plays two different roles in section 6501(e)(1)(A), only one of which its interpretation makes superfluous. Specifically, subsection (i)’s gross income definition affects not only what counts as an “omission from gross income,” but also whether a taxpayer’s total omissions exceed 25 percent “of the amount of gross income stated in the return,” thus triggering the extended period. 26 U.S.C. § 6501(e)(1)(A) (emphasis added). Because its interpretation of “omits from gross income” in no way encroaches on subsection (i)’s second role, Intermountain contends, any redundancy between that interpretation and subsection (i)’s first role is irrelevant.
Intermountain’s point is well taken, but it fails to account fully for subsection (i)’s first role — the one its interpretation admittedly makes irrelevant and that actually led Congress to add subsection (i) in the first place. Recall that Congress added subsection (i) amidst a debate that had divided the courts of appeals and that specifically revolved around whether basis overstatements constituted omissions from gross income.
See supra
696-98. Given that context, it seems obvious that Congress intended subsection (i) to resolve that debate in the taxpayers’ favor, though only in the trade or business context. Indeed, that is exactly how the amendment was contemporaneously understood by the amendment’s supporters, by the parties who argued
Colony,
and by the Supreme Court itself.
See supra
701-02 (citing
Colony,
Perhaps recognizing this problem, the Ninth Circuit suggested that Congress enacted subsection (i) only to clarify the statute’s previous meaning, not to change it.
See Bakersfield,
Finally, Intermountain argues that even if the “omits from gross income” language had an ambiguous meaning when passed in 1954, Congress has since ratified the application of Colony’s interpretation to sections 6501(e)(1)(A) and 6229(c)(2). In support, it points out that Congress reenacted section 6501(e)(1)(A) many times and that it enacted section 6229(c)(2) — all after the Court in Colony definitively interpreted section 275(c)’s corresponding language. This theory, however, collides with our understanding of Colony as interpreting only section 275(c). See supra 701-04. Given that the Supreme Court limited itself to interpreting section 6501(e)(l)(A)’s predecessor, we have no reason to presume from Congress’s silence that it treated that opinion as having authoritatively interpreted section 6501(e)(1)(A) itself. Nor do we see any clear reason to treat section 6229(c)(2) differently, especially since it seems likely that when first enacting that section, Congress intended it to have the same meaning as still-operative section 6501(e)(1)(A) rather than that of long-since defunct section 275(c).
In a post-argument letter filed pursuant to Federal Rule of Appellate Procedure 28(j), Intermountain offers a variation on this reenactment theory based on “the Commissioner’s prior position [i.e., before the Son of BOSS controversy] on the import and effect of the Supreme Court’s decision in
Colony.”
Appellees’ 28(j) Letter 1, Apr. 11, 2011. Intermountain’s unsolicited attempt to introduce a new legal theory based on long-available sources neither included in its brief nor even raised at oral argument comes far too late to warrant our attention.
See United States ex rel. Miller v. Bill Harbert Int’l Const., Inc.,
In sum, because the Court in Colony never purported to interpret section 6501(e)(1)(A); because section 6501(e)(l)(A)’s “omits from gross income” text is at least ambiguous, if not best read to include overstatements of basis; and because neither the section’s structure nor its legislative history nor the context in *706 which it was passed nor its reenactment history removes this ambiguity, we conclude that, outside the trade or business context, nothing in section 6501(e)(1)(A) unambiguously forecloses the Commissioner from interpreting “omissions from gross income” as including basis overstatements. We reach the same conclusion with respect to section 6229(c)(2) in light of Intermountain’s failure to timely raise any argument that the two provisions should be interpreted differently outside the trade or business context. See supra 699-700.
IV.
Given this conclusion, we would ordinarily next analyze the Commissioner’s interpretation of sections 6501(e)(1)(A) and 6229(c)(2) under
Chevron
step two. But Intermountain insists that the Commissioner’s interpretation is entitled to no
Chevron
deference at all. Specifically, it argues that the regulations were promulgated in a manner that lacked “ ‘the fairness and deliberation that should underlie a pronouncement’ meriting
Chevron
deference” given that the “Commissioned ] reactive[ly] issu[ed] ... the [regulations] immediately following the rejection of his identical litigating position by two Courts of Appeals and the Tax Court.” Appellees’ Br. 37 (quoting
United States v. Mead Corp.,
Notwithstanding the rhetorical force of this argument, we agree with the Commissioner that it runs afoul of binding Supreme Court precedent that has, for all practical purposes, superseded
Chock Full O’ Nuts.
As a general matter, the Supreme Court has made crystal clear that it is utterly “irrelevant” to the question of whether
Chevron
deference is due “[t]hat it was litigation which disclosed the need for the regulation.”
Smiley v. Citibank (South Dakota), N.A.,
The partnership in the companion case,
UTAM,
offers another argument for denying
Chevron
deference to the Commissioner — namely, that “[ijnterpreting a statute of limitations [like the ones here] is outside Treasury’s expertise.” Appellee UTAM’s Br. 34,
UTAM, Ltd.,
No. 10-1262 (D.C.Cir. Feb. 7, 2011). UTAM finds some support for this argument in a Third Circuit decision ruling
Chevron
inapplicable to INS’s interpretation of a statute of limitations because “a statute of limitations is a general legal concept with which the judiciary can deal at least as competently as can an executive agency.”
Bamidele v. INS,
Arriving at last at Chevron step two, our task is easy. Intermountain’s only argument that the Commissioner’s interpretation is unreasonable is that it conflicts with Colony. But having held that Colony applies neither to section 6501(e)(1)(A) nor to section 6229(c)(2), see supra 701-05, we see nothing unreasonable in the Commissioner’s decision to diverge from Colony’s holding.
V.
Finally, Intermountain and UTAM advance several arguments for why the regulations neither apply to Intermountain (or UTAM) nor were validly promulgated. We consider each in turn.
Reiterating an argument on which the Tax Court relied, Intermountain first contends that the Commissioner’s regulations are inapplicable to this case under their own “effective/applicability date” provisions. Those provisions state:
Effective/applicability date .... [T]his section applies to taxable years with respect to which the period for assessing tax was open on or after September 24, 2009.
26 C.F.R. §§ 301.6501(e) — 1(e)(1); 301.6229(c)(2)-l(b) (2011); see also 26 C.F.R. §§ 301.6501(e)-lT(b) (2009); 301.6229(c)(2)-lT(b) (The temporary regulations in effect when the Tax Court ruled included a slightly different version of this provision which, with the changes italicized, stated: “The rules of this section apply to taxable years with respect to which the applicable period for assessing tax did not expire before September 24, *708 2009.”). In the preamble to the final regulations, the Commissioner interpreted the phrase “the period for assessing tax” to include “all assessment periods Congress has provided, including the six-year period,” Appellant’s Reply Br. 28, meaning “the final regulations apply to taxable years with respect to which the six-year period for assessing tax under section 6229(c)(2) or 6501(e)(1) was open on or after September 24, 2009,” T.D. 9511, 75 Fed.Reg. at 78,898. The preamble, in turn, explains that a taxable year is “open” if, among other things, it is the “subject of any case pending before any court of competent jurisdiction ... in which a decision had not become final (within the meaning of section 7481).” Id. Finally, section 7481 provides, in effect, that a decision is not final “until the last bell has rung in the last court.” Appellant’s Reply Br. 29. In other words, according to the Commissioner, the regulations apply at least to any taxpayer or partnership whose case was pending in any court at any level on or after September 24, 2009, which all agree includes Intermountain. See also IRS Chief Counsel Notice CC-2010-001 (Nov. 23, 2009) (interpreting “the temporary regulations [to] apply to any docketed Tax Court case in which the period of limitations under sections 6229(c)(2) and 6501(e)(1)(A), as interpreted in the temporary regulations, did not expire with respect to the tax years at issue, before September 24, 2009, and in which no final decision has been entered.”).
Iiitermountain argues that the Commissioner’s interpretation essentially requires us to apply the regulations before determining whether they are even applicable— an approach the Tax Court characterized as “irreparably marred by circular, result-driven logic.”
Intermountain II,
We grant the highest level of deference to an agency’s interpretation of its own regulations, deferring unless the interpretation is “plainly erroneous or inconsistent with the regulation.”
Auer v. Robbins,
Intermountain next contends that applying the regulations under the circumstances of this case would make them impermissibly retroactive. This is so, Intermountain says, because the regulations change settled law — namely,
Colony’s
interpretation of sections 6501(e)(1)(A) and 6229(c)(2) — thus disrupting the expectations of taxpayers or partnerships who filed returns for tax years prior to the regulations’ effective date. We disagree. Because
Colony
never applied to section 6501(e)(1)(A) or section 6229(c)(2),
see supra
701-05, there was no
settled
law for the regulations to change. Given our treatment of
Colony,
the most Intermountain might have argued is that the regulations raise a different sort of retroactivity issue, i.e., that they bring clarity to an area of the law that had been ambiguous during the tax year at issue in this case. But because neither Intermountain nor UTAM makes this particular argument, we decline to consider it.
United States v. Reeves,
Focusing next on the regulatory process, UTAM and amicus Bausch & Lomb urge us not to apply the final regulations because, they say, the Commissioner failed to keep an “open mind” during the notice-and-comment period. Ordinarily, we evaluate an agency’s so-called open-mindedness only when it issues final regulations without the requisite comment period and then tries to cure that Administrative Procedure Act violation by holding a post-promulgation comment period.
See, e.g., Advocates for Highway
<£
Auto Safety v. Fed. Highway Admin.,
Even assuming the applicability of this framework, however, we believe the final regulations were validly promulgated. UTAM and Bausch & Lomb criticize the Commissioner for the preamble’s “silen[ce] regarding the numerous arguments” advanced in voluminous related litigation, Amicus’s Br. 14-15, and for “ma[king] only immaterial changes” in response to those comments, Appellee UTAM’s Br. 55. But an open-mindedness review focuses not on whether the Commissioner responded to
litigants,
but rather on whether he has “afforded the
comments
[received during the comment period] particularly searching consideration.”
Advocates for Highway & Auto Safety,
VI.
In sum, the Commissioner’s regulations were validly promulgated, apply to this ease, qualify for Chevron deference, and pass muster under the traditional Chevron two-step framework. Because the Tax Court concluded otherwise and failed to apply the Commissioner’s interpretation of sections 6501(e)(1)(A) and 6229(c)(2), we reverse that court’s grant of summary judgment. In addition, we remand for the Tax Court to consider Intermountain’s alternative argument, made in the tax court but unaddressed there, that Intermountain avoided triggering the extended statute of limitations by “adequately disclosing] to the IRS the basis amount it applied in connection with the transaction at issue.” Appellees’ Br. 57 (emphasis added) (relying on section 6501(e)(l)(A)(ii)).
So ordered.
