PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


VOLVO TRUCKS OF NORTH AMERICA,          
INCORPORATED, formerly known as
Volvo GM Heavy Truck
Corporation,
                 Plaintiff-Appellant,            No. 03-1256
                 v.
UNITED STATES OF AMERICA,
               Defendant-Appellee.
                                        
            Appeal from the United States District Court
       for the Middle District of North Carolina, at Durham.
               Frank W. Bullock, Jr., District Judge.
                          (CA-01-416-3)

                      Argued: February 24, 2004

                        Decided: May 5, 2004

Before WILKINSON, NIEMEYER, and DUNCAN, Circuit Judges.



Affirmed by published opinion. Judge Niemeyer wrote the opinion,
in which Judge Wilkinson and Judge Duncan joined.


                             COUNSEL

ARGUED: Tamura D. Coffey, WILSON & ISEMAN, Winston-
Salem, North Carolina, for Appellant. Randolph L. Hutter, Tax Divi-
sion, UNITED STATES DEPARTMENT OF JUSTICE, Washington,
D.C., for Appellee. ON BRIEF: G. Gray Wilson, J. Chad Bomar,
2        VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
WILSON & ISEMAN, Winston-Salem, North Carolina, for Appel-
lant. Eileen J. O’Connor, Assistant Attorney General, Richard Farber,
Tax Division, UNITED STATES DEPARTMENT OF JUSTICE,
Washington, D.C., for Appellee.


                              OPINION

NIEMEYER, Circuit Judge:

   Volvo Trucks of North America, Inc. commenced this action
against the Internal Revenue Service ("IRS") to obtain an $856,226
refund of federal excise taxes paid under 26 U.S.C. § 4051(a) for
heavy trucks that Volvo sold to its dealers during the 1989-91 period.
Volvo claimed to be entitled to an exemption from the tax, but the
IRS disallowed the exemption because Volvo failed to support its
claim with the documentation required by Temporary Treasury Regu-
lation § 145.4052-1 (1988).

   Volvo contends (1) that Regulation § 145.4052-1 was an arbitrary
and capricious regulation as promulgated and as applied; (2) that
Volvo substantially complied with the regulation’s requirements; and
(3) that Volvo’s noncompliance with the regulation was attributable
to representations made by IRS agents and therefore that the IRS
should be equitably estopped from disputing Volvo’s refund request.

  The district court dismissed Volvo’s equitable estoppel claim under
Federal Rule of Civil Procedure 12(b)(6), and it granted the IRS’s
motion for summary judgment on the other two claims. For the rea-
sons that follow, we affirm.

                                    I

   Before 1983, the Internal Revenue Code imposed an excise tax on
the first sale by a manufacturer or importer of heavy-duty trucks, but
in 1983, Congress changed the law to impose the 12% tax on the
value of the "first retail sale" of such trucks. 26 U.S.C. §§ 4051, 4052
(1983). Congress defined the "first retail sale" as "the first sale . . .
for a purpose other than for resale or leasing in a long-term lease." 

OF NORTH AMERICA v. UNITED STATES              3
§ 4052(a)(1). Under this scheme, manufacturers and importers would
be exempt from excise tax on trucks sold to their dealers for resale,
and their dealers would pay the tax. For trucks that the dealers pur-
chased for their own use, however, the manufacturer or the importer
would have to pay the tax. Temporary Treasury Regulation
§ 145.4052-1 was promulgated in 1988 to provide the mechanism by
which the IRS collected this tax.

   Section 4052 authorized the IRS to promulgate regulations, direct-
ing the IRS to prescribe rules "similar to the rules of . . . section
4222." 26 U.S.C. § 4052(d) (later amended by Pub. L. No. 105.34,
§ 1434(b)(1) (1997)). Under § 4222, which governs a different set of
tax exemptions, taxpayers are required to register with the IRS before
they can be eligible for the exemptions. 

In addition to
the registration requirement, parties to sales governed by § 4222 must,
as required by regulations promulgated under § 4222, also provide the
IRS with a written statement establishing the nontaxable nature of
each sale. 26 C.F.R. §§ 48.4222(a)(1)(c), 48.4221-1(c). Acting on
§ 4052’s instruction to use § 4222 as a guide in establishing regula-
tions for § 4052, the IRS promulgated Temporary Treasury Regula-
tion 26 C.F.R. § 145.4052-1 (1988).

   Regulation § 145.4052-1(a) provided that in order for a
manufacturer-seller to be exempt from the excise tax imposed under
§ 4051, both the manufacturer-seller and the dealer-purchaser had to
be registered with the IRS. In addition, the manufacturer-seller must
have obtained from the dealer-purchaser a signed certificate that
included the dealer’s registration number and indicated that the trans-
action was for resale or long-term lease.

   Volvo Trucks of North America, Inc. ("Volvo"), a manufacturer of
heavy trucks and truck parts, responded to this regulation by instruct-
ing each of its franchised dealers to register with the IRS and to pro-
vide Volvo with exemption certificates that indicated the dealer’s
registration number and that listed the trucks purchased for resale.
Two such dealers, Atlas Engine Rebuilders, Inc. ("Atlas") and Alaska
Sales and Service, Inc. ("Alaska"), sent Volvo certificates with the
phrase "Applied For" in the field reserved for its IRS registration
number, indicating that they had applied for but not yet received a
registration number for the relevant period. Another dealer, Alameda
4         VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
Truck Center, Inc. ("Alameda"), never supplied Volvo with a certifi-
cate. There is evidence that despite their failure to produce the certifi-
cates to Volvo, Alaska and Alameda had in fact registered with the
IRS.

   In 1991, the IRS began two excise tax audits of Volvo, one cover-
ing the period 1989-90 and the second covering 1990-91. At the end
of the audits, the IRS assessed Volvo with over $2.1 million in excise
taxes and penalties to cover those sales transactions that it had with
dealers for which Volvo had not produced completed dealer certifica-
tions. Volvo paid the assessed amount and pursued administrative
appeals. During this administrative process, the IRS refunded taxes to
Volvo for transactions where the IRS could confirm that the dealer
had paid the excise tax, even if the dealer had not properly registered
and had not properly certified the transaction. As a result of this pro-
cess, Volvo’s liability for excise taxes was reduced from over $2.1
million to $856,226.08. Volvo commenced this action seeking a
refund of this remaining amount.

   In its complaint, Volvo contends (1) that Temporary Treasury Reg-
ulation § 145.4052-1 was invalid because it was an arbitrary and
capricious regulation; (2) that Volvo substantially complied with Reg-
ulation § 145.4052-1; and (3) that the IRS should in any event be
equitably estopped from enforcing the regulation because, during the
administrative process, IRS made representations on which Volvo
relied in failing to produce the required documentation. With respect
to the equitable estoppel claim, Volvo alleged that IRS agents told
Volvo that it did not need to have exemption certificates, but the IRS
later changed its position; that IRS agents told Volvo that exemption
certificates would apply retroactively but then denied their retroactive
effect; and that IRS agents told Volvo that the IRS would accept affi-
davits in lieu of certifications but then refused to accept affidavits.

  The district court granted the IRS’s motion for summary judgment
on Volvo’s first two claims relating to Regulation § 145.4052-1 and
Volvo’s compliance with it, and it granted the IRS’s motion to dis-
miss the third claim relating to equitable estoppel on the ground that
Volvo failed to state a claim upon which relief could be granted. This
appeal followed.
         VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES               5
                                   II

   Volvo contends first that the promulgation of Temporary Treasury
Regulation § 145.4052-1 was an invalid exercise of the IRS’s rule-
making authority. More particularly, Volvo argues that (1) Regulation
§ 145.4052-1 was inconsistent with 26 U.S.C. § 4052, which autho-
rized the regulation; (2) the regulation was inconsistent with congres-
sional intent; (3) the IRS failed to consider the possibility of double-
taxation in promulgating the regulation; and (4) the regulation was not
"uniformly or literally applied" in all circumstances. We address these
arguments seriatum.

   On Volvo’s first argument that the regulation was inconsistent with
the statute, we conclude that the regulation was not only consistent
with the plain language of the statute, but it was explicitly contem-
plated by the statute. In § 4052, Congress authorized the IRS to pro-
mulgate regulations "similar to the rules of . . . section 4222." 26
U.S.C. § 4052(d)(2). Section 4222 requires that all parties to a sale be
registered with the IRS as a condition to receiving the tax exemptions
that are detailed in § 4221. In addition, the regulations promulgated
under §§ 4221 and 4222 require that purchasers provide sellers with
written statements that include their IRS registration numbers and the
nontaxable purpose for which the items were purchased. 26 C.F.R.
§§ 48.4222(a)-(1)(c), 48.4221-1(c). Thus, when Congress specifically
instructed the IRS in § 4052 to promulgate regulations similar to
those in § 4222, it directed the Commissioner to impose registration
and certification requirements in connection with sales covered by
§ 4052.

   The Commissioner did just that. When the IRS promulgated Tem-
porary Treasury Regulation § 145.4052-1, it was only complying with
the explicit requirements of § 4052. As with § 4221 and its imple-
menting regulations, the IRS required with respect to § 4052 that
manufacturer-sellers and dealer-purchasers be registered with the IRS
under § 4222 and that the manufacturers obtain exemption certificates
containing statements from the dealer-purchasers that the trucks being
sold were for resale or long-term leasing. Even if § 4052 had not
explicitly authorized such a regulatory scheme, however, Regulation
§ 145.4052-1 would have been a reasonable promulgation designed to
verify that the excise tax had been paid by the dealer before exempt-
6        VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
ing the manufacturer. It therefore would undoubtedly have been
within the IRS’s authority.

   As for Volvo’s argument that the regulation violated congressional
intent, there is little need to address this point further because, as
already noted, the IRS received explicit authority to promulgate the
regulation. Moreover, Congress’ intent to authorize such a regulation
is manifested by the fact that in later changing the language of § 4052,
Congress, albeit a different Congress, recognized that it was adopting
a new requirement that called for less documentation than it had
required in the 1983 version of § 4052. See 26 U.S.C. § 4052(g)
(2003) (deleting the registration requirement and authorizing the
endorsement of a simple affidavit by the purchasing dealer on the
sales invoice that "such sale is for resale"). In recognizing that the
registration and certification requirements of the 1983 version of
§ 4052 were too onerous, Congress also recognized that it would have
to rewrite the old version before the Commissioner could discard
those onerous requirements. Thus, Congress recognized that, at the
time the IRS promulgated Temporary Treasury Regulation
§ 145.4052-1 (1988), it was the then-current Congress’ intent that the
IRS issue such a regulation.

   Volvo also argues that the regulation was arbitrary and capricious
in that it created the possibility of double taxation. This argument,
however, is not based on the traditional understanding of double taxa-
tion — referring to taxing a single transaction twice — because, in the
circumstances before us, there are actually two transactions in play:
the sale by the manufacturer to the dealer and the sale by the dealer
to the user. Even if both transactions were taxed, the taxation would
not amount to double taxation in the traditional sense. Using "double
taxation" in a nontraditional sense, as Volvo would prefer for its argu-
ment — i.e., to refer to any instance where a taxpayer pays a tax for
which it could have been exempt — would render almost any docu-
mentation requirement violative of this "double taxation" prohibition.
Tax exemptions generally rely on taxpayers’ ability to prove their eli-
gibility, and the IRS’s actions in demanding such proof are not arbi-
trary and capricious merely because some taxpayers do not take
advantage of all exemptions. Volvo has no legal authority or plausible
legal theory to support its argument that the fact that its noncompli-
         VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES                7
ance could result in taxation to both Volvo and its dealers renders the
IRS’s regulation arbitrary or capricious.

   Finally, Volvo makes the astonishing argument that in order to
avoid arbitrariness and capriciousness, "an administrative agency
must uniformly apply its regulations to all applicable situations."
Such a standard would be impossible for any agency to achieve. The
inherently discretionary nature of enforcement duties means that, in
the absence of an unconstitutional motive, the agency cannot be
required to apply each of its regulations mechanically to every situa-
tion that falls under them.

   In sum, we find no merit in any of Volvo’s arguments that Tempo-
rary Treasury Regulation § 145.4052-1 was invalid.

                                   III

   Volvo next contends that it "made a good faith effort to comply"
with Temporary Treasury Regulation § 145.4052-1 and that, under
the doctrine of substantial compliance, it is entitled to a refund. Volvo
asserts that its substantial compliance with the regulation is a question
of fact that cannot be properly resolved by summary judgment and
that therefore we must remand this issue to the district court for trial.
Even as Volvo recognizes that it failed to obtain proper certifications
from three dealers — Atlas, Alaska, and Alameda — it proffers in
support of its substantial compliance claim evidence that suggests that
Alameda and Alaska were registered with the IRS and that they paid
some of the required excise taxes. Volvo also suggests that Alaska’s
and Alameda’s forms demonstrating payment of the excise tax have
been destroyed by the IRS. Finally, Volvo has presented evidence that
it made good-faith efforts to obtain certifications from its dealers but
that the dealers did not provide them. At bottom, it maintains that the
establishment of these facts and more would justify a factfinder’s
determination that Volvo had substantially complied with Regulation
§ 145.4052-1.

   At the outset, it must be noted that in circumstances where the IRS
was able to determine from its own records that Volvo’s dealers paid
the excise tax, the IRS refunded taxes to Volvo. Indeed, in response
to such an investigation, the IRS reduced its initial assessment of $2.1
8        VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
million to $856,226. The IRS presses its claim for excise taxes from
Volvo in the circumstances where it has no record that the excise
taxes were paid.

    Substantial compliance, as applied to tax regulation requirements,
must be seen as a limited exception to the general rule that "equitable
considerations are of limited consequence" in interpreting tax law
because "tax laws are technical and, for the most part, are to be
accordingly interpreted." Hull v. United States, 

, 238
(4th Cir. 1998) (internal quotation marks and citations omitted). Even
so, the Tax Court has accepted substantial compliance with regulatory
requirements when the requirements "are procedural and when the
essential statutory purposes have been fulfilled." American Air Filter
Co. v. Commissioner, 

(1983). We have recognized a sim-
ilar formulation, inquiring whether the failure to comply with a regu-
latory requirement "goes to the ‘essence’ of the provision, or whether
it is merely a relatively ancillary, minor procedural infirmity." Atlan-
tic Veneer Corp. v. Commissioner, 

, 161 (4th Cir. 1987).
Believing that the dichotomy between "essential" and "procedural"
for this purpose is not satisfactory, the Seventh Circuit has suggested
a formulation that "[t]he common law doctrine of substantial compli-
ance should not be allowed to spread beyond cases in which the tax-
payer had a good excuse (though not a legal justification) for failing
to comply with either an unimportant requirement or one unclearly or
confusingly stated in the regulations or the statute." Prussner v.
United States, 

, 224 (7th Cir. 1990) (en banc) (emphasis
added). To that end, before the doctrine of substantial compliance
could apply, there would have to be "a showing that the [regulatory]
requirement is either unimportant or unclearly or confusingly stated."

And drawing on Prussner, the Fifth Circuit has articu-
lated a similar formulation, holding that "substantial compliance is
achieved where the regulatory requirement at issue is unclear and a
reasonable taxpayer acting in good faith and exercising due diligence
nevertheless fails to meet it." McAlpine v. Commissioner, 

, 462 (5th Cir. 1992).

   All of these formulations seek to preserve the need to comply
strictly with regulatory requirements that are important to the tax col-
lection scheme and to forgive noncompliance for either unimportant
and tangential requirements or requirements that are so confusingly
          VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES                 9
written that a good faith effort at compliance should be accepted.
Stated otherwise, a taxpayer may be relieved of perfect compliance
with a regulatory requirement when the taxpayer has made a good
faith effort at compliance or has a "good excuse" for noncompliance,
and (1) the regulatory requirement is not essential to the tax collection
scheme but rather is an unimportant or "relatively ancillary require-
ment" or (2) the regulatory provision is so confusingly written that it
is reasonably subject to conflicting interpretations.

   When we apply such a formulation to this case, we readily con-
clude that Volvo cannot have the benefit of substantial compliance in
the circumstances presented. Regulation § 145.4052-1 was clear and
unambiguous in requiring that Volvo and its dealers register with the
IRS in accordance with § 4222 and that Volvo produce exemption
certificates from its dealers with respect to trucks sold to the dealer
for resale or for a long-term lease. Moreover, this provision was
essential to the IRS’s tax collection effort in that it demonstrated
which party was responsible for the excise tax imposed by § 4051.
The statute created a presumption that any sale, including the manu-
facturer’s sale to the dealer was, a "first retail sale," and therefore the
manufacturer owed the tax unless the dealer certified that it was pur-
chasing the vehicle for resale. Thus, for example, if the dealer were
purchasing trucks for its own use or for a business of daily rentals,
the manufacturer would have to pay the excise tax itself. But if the
dealer were purchasing trucks for resale or long-term leasing and so
certified, the manufacturer would not have to pay the tax. Volvo’s
failure to provide the required demonstration that its dealers were pur-
chasing trucks for resale thus left the tax regulation in its default
application, requiring Volvo to pay the excise tax.

    The requirements of Regulation § 145.4052-1 are not ancillary or
unimportant; they go to the essence of who owes the tax and how the
IRS can collect it. And the regulation itself established the importance
of the documentation by requiring it as a condition precedent to the
manufacturer’s exemption, providing that "[t]he sale of an article is
a taxable sale unless" the registration and certification requirements
are met. Temp. Treas. Reg. § 145.4052-1(a)(2) (1988). In treating ful-
fillment of these requirements as a condition precedent to eligibility,
the IRS had support in its authorizing statute. Section 4222, on which
Congress directed the IRS to model its § 4052 regulations, treats reg-
10        VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
istration as a condition precedent for a manufacturer taxpayer to avail
itself of § 4221’s exemption. See 26 U.S.C. § 4222(a) (providing that
the exemption "shall not apply . . . unless the [parties] are all regis-
tered under this section"). Thus, by referring to § 4222, § 4052
directed the IRS to treat registration as a condition precedent for eligi-
bility for the tax exemption in § 4051. The IRS was therefore within
its authority to require registration as a condition precedent to eligibil-
ity for the manufacturer’s exemption, rather than to treat it as an
unimportant procedural matter. Accordingly, the doctrine of substan-
tial compliance cannot be applied in this case because it would excuse
noncompliance with essential regulatory requirements.

   We should note that were we required to reach other aspects of the
substantial compliance formulation, we would have to question
whether Volvo’s efforts to comply with Regulation § 145.4052-1
were in fact made in good faith. In its complaint and its brief on
appeal, Volvo has claimed that it relied on IRS agents’ misrepresenta-
tions regarding the requirements in Regulation § 145.4052-1 even
though the regulation was clear and it understood its requirements.
Thus, Volvo alleged in its complaint that it did not take "steps to
obtain exemption certificates from its noncompliant dealers." Simi-
larly in its brief on appeal, it stated, "Absent the IRS agents retreating
from their statements, Volvo would have followed the registration
requirements and obtained exemption certificates." In other words,
Volvo has actually acknowledged that it could have complied with
Regulation § 145.4052-1 but chose not to. Instead, it relied on indi-
vidual IRS agents’ assurances that it did not have to comply with the
regulation. No formulation of the substantial compliance doctrine
would award a tax refund to a taxpayer in these circumstances.

                                    IV

   Finally, Volvo contends that the district court erred in dismissing
its claim for a refund based on its allegations that the IRS should be
equitably estopped from enforcing Temporary Treasury Regulation
§ 145.4052-1 against Volvo because individual IRS agents told Volvo
it did not have to comply with the requirements of the regulation.

  In its complaint, Volvo alleged three instances when IRS agents
misrepresented what was required to satisfy Regulation § 145.4052-1.
          VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES               11
First, it alleged that during the first audit cycle, begun in 1991, an IRS
agent told Volvo that it did not need exemption certificates, but that
the IRS later changed its position. By this time, Volvo claimed, it
could not have obtained the required documentation. Second, it
alleged that also during the first audit cycle, the IRS’s manager told
Volvo that exemption certificates would apply retroactively to qualify
as tax-exempt prior transactions between Volvo and the dealers. Dur-
ing the second audit cycle, however, another agent denied retroactive
effect to the certificates. Third and finally, Volvo alleged that some-
time after February 13, 1995, an appeals officer told Volvo that the
IRS would accept affidavits in lieu of the specified certifications, but
the IRS did not do so. Volvo claims that it suffered a detriment in
receiving this misinformation because it "expended substantial
resources in obtaining" affidavits.

   Equitable estoppel against the government is strongly disfavored,
if not outright disallowed, because it allows parties to collect public
funds in a situation not expressly authorized by Congress. Courts
should not "order[ ] recovery contrary to the terms of the regulation,
for to do so would disregard ‘the duty of all courts to observe the con-
ditions defined by Congress for charging the public treasury.’" OPM
v. Richmond, 

, 420 (1990) (quoting Federal Crop Ins.
Corp. v. Merrill, 

, 385 (1947)); see also Miller v. United
States, 

, 712 (4th Cir. 1991). If equitable estoppel ever
applies to prevent the government from enforcing its duly enacted
laws, it would only apply in extremely rare circumstances. In "leav-
[ing] for another day whether an estoppel claim could ever succeed
against the Government," the Supreme Court has ominously observed
that "we have reversed every finding of estoppel that we have
reviewed." 

.

   In this case, each of Volvo’s allegations relates to an IRS agent’s
misrepresentation of the requirements of law, and it is well settled that
reliance upon statements or actions contrary to law is not reasonable.
See Fredericks v. Commissioner, 

, 443 (3d Cir. 1997)
("[A] private party’s reliance on governmental actions or omissions
is not reasonable if such acts or omissions are contrary to the law");
see also 

; Goldberg v. Weinberger, 

, 481 (2d Cir. 1976); Posey v. United States, 

, 233-
34 (5th Cir. 1997). Equitable estoppel requires reasonable reliance,
12       VOLVO TRUCKS OF NORTH AMERICA v. UNITED STATES
and we conclude that Volvo could not reasonably have relied upon
individual IRS agent’s representations that the unambiguous provi-
sions of the law need not have been obeyed. Accordingly, we affirm
the district court’s dismissal of Volvo’s claim based on equitable
estoppel.

                                  V

   For the reasons given, we affirm the district court’s summary judg-
ment entered on Volvo’s claims that Temporary Treasury Regulation
§ 145.4052-1 was arbitrary and capricious and that Volvo substan-
tially complied with the regulation’s requirements. We also affirm the
district court’s order dismissing Volvo’s claim for equitable estoppel
under Federal Rule of Civil Procedure 12(b)(6) for failure to state a
claim upon which relief could be granted.

                                                         AFFIRMED