JUSTICE WHITE delivered the opinion of the Court.In these cases, we review an application of the so-called "zone of interest" standing test that was first articulated in Association of Data Processing Service Organizations, Inc. v. Camp, 397 U. S. 150 (1970).  Concluding that respondent is a proper litigant, we also review, and reverse, a judgment that the Comptroller of the Currency exceeded his authority in approving the applications of two national banks for the establishment or purchase of discount brokerage subsidiaries.IIn 1982, two national banks, Union Planters National Bank of Memphis (Union Planters) and petitioner Security Pacific National Bank of Los Angeles (Security Pacific), applied to the Comptroller of the Currency for permission to open offices that would offer discount brokerage services to the public. [Footnote 1]  Page 479 U. S. 391 Union Planters proposed to acquire an existing discount brokerage operation, and Security Pacific sought to establish an affiliate named Discount Brokerage.  Both banks proposed to offer discount brokerage services not only at their branch offices but also at other locations inside and outside of their home States.In passing on Security Pacific's application, the Comptroller was faced with the question whether the operation of Discount Brokerage would violate the National Bank Act's branching provisions.  Those limitations, enacted as §§ 7 and 8 of the McFadden Act, 44 Stat. 1228, as amended, are codified at 12 U.S.C. § 36 and 12 U.S.C. § 81.  Section 81 limits "the general business" of a national bank to its headquarters and any "branches" permitted by § 36.  Section 36(c) provides that a national bank is permitted to branch only in its home State, and only to the extent that a bank of the same State is permitted to branch under state law.  The term "branch" is defined at 12 U.S.C. § 36(f)"to include any branch bank, branch office, branch agency, additional office, or any branch place of business . . . at which deposits are received, or checks paid, or money lent."The Comptroller concluded that"the non-chartered offices at which Discount Brokerage will offer its services will not constitute branches under the McFadden Act because none of the statutory branching functions will be performed there."App. D to Pet. for Cert. in No. 85-971, p. 39a.  He explained that, although Discount Brokerage would serve as an intermediary for margin lending, loan approval would take place at chartered Security Pacific offices, so that Discount Brokerage offices would not be lending money within the meaning of § 36(f).  Likewise, although Discount Brokerage Page 479 U. S. 392 would maintain, and pay interest on, customer balances created as an incident of its brokerage business, the Comptroller concluded that these accounts differ sufficiently in nature from ordinary bank accounts that Discount Brokerage would not be engaged in receiving deposits. [Footnote 2]  He further observed that treating offices conducting brokerage activities as branches under § 36(f) would be inconsistent with the "longstanding and widespread" practice of banks' operating nonbranch offices dealing in United States Government or municipal securities.  Id. at 44a.  Accordingly, the Comptroller approved Security Pacific's application. [Footnote 3]Respondent, a trade association representing securities brokers, underwriters, and investment bankers, brought this action in the United States District Court for the District of Columbia.  Among other things, respondent contended that bank discount brokerage offices are branches within the meaning of § 36(f), and thus are subject to the geographical Page 479 U. S. 393 restrictions imposed by § 36(c). [Footnote 4]  The Comptroller disputed this position on the merits, and also argued that respondent lacks standing because it is not within the zone of interests protected by the McFadden Act. [Footnote 5]  The Comptroller contended that Congress passed the McFadden Act not to protect securities dealers, but to establish competitive equality between state and national banks.The District Court, relying on Association of Data Processing Service Organizations, Inc. v. Camp, 397 U. S. 150 (1970), held that respondent has standing and rejected the Comptroller's submission that national banks may offer discount brokerage services at nonbranch locations.  A divided panel of the Court of Appeals affirmed in a brief per curiam opinion, [Footnote 6] 244 U.S.App.D.C. 419, 758 F.2d 739 (1985), and rehearing en banc was denied, with three judges dissenting.  247 U.S.App.D.C. 42, 765 F.2d 1196 (1985). Page 479 U. S. 394The Comptroller sought review by petition for certiorari, as did Security Pacific.  We granted both petitions, and consolidated the cases.  475 U.S. 1044 (1986).  We now affirm the judgment that respondent has standing, but reverse on the merits.IIIn Association of Data Processing Service Organizations, Inc. v. Camp, supra, the association challenged a ruling by the Comptroller allowing national banks, as part of their incidental powers under 12 U.S.C. § 24 Seventh, to make data processing services available to other banks and to bank customers.  There was no serious question that the data processors had sustained an injury in fact by virtue of the Comptroller's action.  Rather, the question, which the Court described as one of standing, was whether the data processors should be heard to complain of that injury.  The matter was basically one of interpreting congressional intent, [Footnote 7] and the Court looked to § 10 of the Administrative Procedure Act (APA), 5 U.S.C. § 702, which "grants standing to a person aggrieved by agency action within the meaning of a relevant statute.'"  397 U.S. at  397 U. S. 153.  The Court of Appeals had interpreted § 702 as requiring either the showing of a "legal interest," as that term had been narrowly construed in our earlier cases, e.g., Tennessee Electric Power Co. v. TVA, 306 U. S. 118,  306 U. S. 137 (1939), or alternatively as requiring an explicit provision in the relevant statute permitting suit by any party "adversely affected or aggrieved." [Footnote 8]  See Association of Data Processing Service Organizations, Inc. v. Camp, 406 Page 479 U. S. 395 F.2d 837 (CA8 1969).  This Court was unwilling to take so narrow a view of the APA's "`generous review provisions,'" 397 U.S. at  397 U. S. 156 (quoting Shaughnessy v. Pedreiro, 349 U. S. 48,  349 U. S. 51 (1955)), and stated that, in accordance with previous decisions, the Act should be construed "not grudgingly, but as serving a broadly remedial purpose," ibid. (citing Shaughnessy, supra, and Rusk v. Cort, 369 U. S. 367,  369 U. S. 379-380 (1962)).  Accordingly, the data processors could be "within that class of `aggrieved' persons who, under § 702, are entitled to judicial review of `agency action,'" 397 U.S. at  397 U. S. 157, even though the National Bank Act itself has no reference to aggrieved persons, and, for that matter, no review provision whatsoever. [Footnote 9]  It was thought, however, that Congress, in enacting § 702, had not intended to allow suit by every person suffering injury in fact.  What was needed was a gloss on the meaning of § 702.  The Court supplied this gloss by adding to the requirement that the complainant be "adversely affected or aggrieved," i.e., injured in fact, the Page 479 U. S. 396 additional requirement that"the interest sought to be protected by the complainant [be] arguably within the zone of interests to be protected or regulated by the statute or constitutional guarantee in question."Id. at 153.The Court concluded that the data processors were arguably within the zone of interests established by § 4 of the Bank Page 479 U. S. 397 Service Corporation Act of 1962, 76 Stat. 1132, 12 U.S.C. § 1864, which forbids bank service corporations to "engage in any activity other than the performance of bank services for banks."  See 397 U.S. at  397 U. S. 155.  In so holding, the Court relied on a brief excerpt from the legislative history of § 4 indicating that Congress intended to enforce adherence to "the accepted public policy which strictly limits banks to banking."  Ibid. (internal quotations omitted). [Footnote 10]  The data processors were therefore permitted to litigate the validity of the Comptroller's ruling.The "zone of interest" formula in Data Processing has not proved self-explanatory, [Footnote 11] but significant guidance can nonetheless be drawn from that opinion.  First.  The Court interpreted the phrase "a relevant statute" in § 702 broadly; the data processors were alleging violations of 12 U.S.C. § 24 Seventh, see 397 U.S. at  397 U. S. 157, n. 2, yet the Court relied on the legislative history of a much later statute, § 4 of the Bank Service Corporation Act of 1962, in holding that the data processors satisfied the "zone of interest" test.  Second.  The Court approved the "trend . . . toward [the] enlargement of the class of people who may protest administrative action."  397 U.S. at  397 U. S. 154.  At the same time, the Court implicitly recognized the potential for disruption inherent in allowing every party adversely affected by agency action to seek judicial review.  The Court struck the balance in a manner favoring review, but excluding those would-be plaintiffs not even "arguably within the zone of interests to be protected or regulated by the statute. . . ."  Id. at  397 U. S. 153. [Footnote 12]The reach of the "zone of interest" test, insofar as the class of potential plaintiffs is concerned, is demonstrated by the subsequent decision in Investment Company Institute v. Camp, 401 U. S. 617 (1971).  There, an association of open-end investment companies and several individual investment companies sought, among other things, review of a Comptroller's regulation that authorized banks to operate collective investment funds.  The companies alleged that the regulation violated the Glass-Steagall Banking Act of 1933, which prohibits banks from underwriting or issuing securities.  See 12 U.S.C. § 24 Seventh.  The Comptroller urged that the plaintiffs lacked standing, to which the Court responded that plaintiffs not only suffered actual injury but, as in Data Processing, suffered injury from the competition that Congress had arguably legislated against by limiting the activities available to national banks. [Footnote 13] Page 479 U. S. 398Justice Harlan, in dissent, complained that there was no evidence that Congress had intended to benefit the plaintiff's class when it limited the activities permitted national banks.  The Court did not take issue with this observation; it was enough to provide standing that Congress, for its own reasons, primarily its concern for the soundness of the banking system, had forbidden banks to compete with plaintiffs by entering the investment company business. Page 479 U. S. 399Our decision in Block v. Community Nutrition Institute, 467 U. S. 340 (1984), provides a useful reference point for understanding the "zone of interest" test.  There we held that, while milk handlers have the right to seek judicial review of pricing orders issued by the Secretary of Agriculture under the Agricultural Marketing Agreement Act of 1937, consumers have no such right, because "[a]llowing consumers to sue the Secretary would severely disrupt [the] complex and delicate administrative scheme."  Id. at  467 U. S. 348.  We recognized the presumption in favor of judicial review of agency action, but held that this presumption is "overcome whenever the congressional intent to preclude judicial review is fairly discernible in the statutory scheme.'"  Id. at  467 U. S. 351 (quoting Data Processing, 397 U.S. at  397 U. S. 157).  The essential inquiry is whether Congress "intended for [a particular] class [of plaintiffs] to be relied upon to challenge agency disregard of the law."  467 U.S. at  467 U. S. 347 (citing Barlow v. Collins, 397 U. S. 159,  397 U. S. 167 (1970)).The "zone of interest" test is a guide for deciding whether, in view of Congress' evident intent to make agency action presumptively reviewable, a particular plaintiff should be heard to complain of a particular agency decision.  In cases where the plaintiff is not itself the subject of the contested regulatory action, the test denies a right of review if the plaintiff's interests are so marginally related to or inconsistent with the purposes implicit in the statute that it cannot reasonably be assumed that Congress intended to permit the suit.  The test is not meant to be especially demanding; [Footnote 14] in particular, there need be no indication of congressional purpose Page 479 U. S. 400 to benefit the would-be plaintiff.  Investment Company Institute v. Camp, 401 U. S. 617 (1971). [Footnote 15]The inquiry into reviewability does not end with the "zone of interest" test.  In Community Nutrition Institute, the interests of consumers were arguably within the zone of interests meant to be protected by the Act, see 467 U.S. at  467 U. S. 347, but the Court found that point not dispositive because, at bottom, the reviewability question turns on congressional intent, and all indicators helpful in discerning that intent must be weighed. [Footnote 16] Page 479 U. S. 401In considering whether the "zone of interest" test provides or denies standing in these cases, we first observe that the Comptroller's argument focuses too narrowly on 12 U.S.C. § 36, and does not adequately place § 36 in the overall context of the National Bank Act.  As Data Processing demonstrates, we are not limited to considering the statute under which respondents sued, but may consider any provision that helps us to understand Congress' overall purposes in the National Bank Act.  See supra at  479 U. S. 396.Section 36 is a limited exception to the otherwise applicable requirement of § 81 that "the general business of each national banking association shall be transacted in the place specified in its organization certificate. . . ."  Prior to the enactment of § 36, § 81 had been construed to prevent branching by national banks.  Lowry National Bank, 29 Op.Atty.Gen. 81 (1911), approved in First National Bank in St. Louis v. Missouri, 263 U. S. 640,  263 U. S. 656-659 (1924).  We have described the circumstances surrounding the enactment of § 36 as part of the McFadden Act, and its subsequent modification by the amendments added through the Bank Act of 1933, in First National Bank of Logan v. Walker Bank & Trust Co., 385 U. S. 252 (1966), and we will not repeat that history in Page 479 U. S. 402 detail here.  It is significant for our present inquiry that Congress rejected attempts to allow national banks to branch without regard to state law.  See id. at  385 U. S. 259.  There were many expressions of concern about the effects of branching among those who supported the McFadden Act, as well as among its opponents.  Allusion was made to the danger that national banks might obtain monopoly control over credit and money if permitted to branch.  66 Cong.Rec. 4438 (1925) (remarks of Sen. Reed).  The sponsor of the Act himself stated that "[t]his bill is much more an anti-branch-banking bill than a branch-banking bill."  Id. at 1582 (remarks of Rep. McFadden). [Footnote 17]  In short, Congress was concerned not only with equalizing the status of state and federal banks, but also with preventing the perceived dangers of unlimited branching. Page 479 U. S. 403The interest respondent asserts has a plausible relationship to the policies underlying §§ 36 and 81 of the National Bank Act.  Congress has shown a concern to keep national banks from gaining a monopoly control over credit and money through unlimited branching.  Respondent's members compete with banks in providing discount brokerage services -- activities which give banks access to more money, in the form of credit balances, and enhanced opportunities to lend money, viz., for margin purchases.  "Congress [has] arguably legislated against the competition that [respondent seeks] to challenge," Investment Company Institute, 401 U.S. at  401 U. S. 620, by limiting the extent to which banks can engage in the discount brokerage business, and hence limiting the competitive impact on nonbank discount brokerage houses.These cases can be analogized to Data Processing and Investment Company Institute.  In those cases the question was what activities banks could engage in at all; here, the question is what activities banks can engage in without regard to the limitations imposed by state branching law.  In both cases, competitors who allege an injury that implicates the policies of the National Bank Act are very reasonable candidates to seek review of the Comptroller's rulings.  There is sound reason to infer that Congress "intended [petitioner's] class [of plaintiffs] to be relied upon to challenge agency disregard of the law."  Community Nutrition Institute, 467 U.S. at  467 U. S. 347.  And we see no indications of the kind presented in Community Nutrition Institute that make "fairly discernible" a congressional intent to preclude review at respondent's behest.  We conclude, therefore, that respondent was a proper party to bring this lawsuit, and we now turn to the merits.III"It is settled that courts should give great weight to any reasonable construction of a regulatory statute adopted by the agency charged with Page 479 U. S. 404 the enforcement of that statute.  The Comptroller of the Currency is charged with enforcement of banking laws to an extent that warrants the invocation of this principle with respect to his deliberative conclusions as to the meaning of these laws.  See First National Bank v. Missouri, 263 U. S. 640,  263 U. S. 658."Investment Company Institute v. Camp, supra, at  401 U. S. 626-627.  See also, e.g., United States v. Riverside Bayview Homes, Inc., 474 U. S. 121 (1985); Chemical Manufacturers Assn. v. Natural Resources Defense Council, Inc., 470 U. S. 116 (1985); Chevron U.S.A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984).Respondent contends that the Comptroller's interpretation of the Bank Act is not entitled to deference, because it contradicts the plain language of the statute.  Respondent relies on 12 U.S.C. § 81, which provides:"The general business of each national banking association shall be transacted in the place specified in its organization certificate and in the branch or branches, if any, established or maintained by it in accordance with the provisions of section 36 of this title."In respondent's view, the unambiguous meaning of § 81 is that "national banks may locate their business only at their headquarters or licensed branches within the same state."  Brief for Respondent 11.  However, § 81 is considerably more ambiguous than respondent allows.  The phrase "[t]he general business of each national banking association" in § 81 need not be read to encompass all the business in which the bank engages, but, as we shall explain, can plausibly be read to cover only those activities that are part of the bank's core banking functions.Prior to 1927, the predecessor of § 81 (Rev. Stat. § 5190) provided that"the usual business of each national banking association shall be transacted at an office or banking-house located in the place specified in its organization certificate."In Lowry National Bank, 29 Op.Atty.Gen. 81 (1911), the Page 479 U. S. 405 Attorney General interpreted this statute to permit"a bank [to] maintain an [extra-office] agency, the power of which is restricted to dealing in bills of exchange, or possibly to some other particular class of business incident to the banking business,"but to forbid "a bank to establish a branch for the transaction of a general banking business."  Id. at 86.  The Attorney General went on to cite cases which he viewed as"recogniz[ing] a vital distinction between a mere agency for the transaction of a particular business and a branch bank wherein is carried on a general banking business."Id. at 87.  He summarized the distinction as follows:"An agency requires no division of the capital stock, and the details of the business are few and are easily supervised by the officers of the bank, while a branch bank requires, in effect, a division of the capital, the working force is organized, and the business conducted as if it were a separate organization, and it competes in all branches of the banking business with other banks in that locality the same as if it were an independent institution."Id. at 87-88.  The Court subsequently approved this interpretation of § 5190 in First National Bank in St. Louis v. Missouri, 263 U.S. at  263 U. S. 658.The Lowry National Bank opinion, which is part of the background against which Congress legislated when it passed the McFadden Act in 1927, does not interpret § 5190 as requiring national banks to conduct all of their business at the central office.  The opinion equates "the usual business of banking" with "a general banking business," and envisions branching in terms of the performance of core banking functions.Respondent attempts to sidestep the Lowry opinion by arguing that Congress changed the meaning of § 5190 when, in passing the McFadden Act, it changed the words "the usual business of each national banking association" to "the general business of each national banking association."  Respondent Page 479 U. S. 406 has pointed to nothing in the legislative history of the McFadden Act, however, indicating that this change in the wording had substantive significance.  We find reasonable the Comptroller's position that "the amendment simply codified the accepted notion that the usual business' of a bank was the `general banking business.'"  Reply Brief for Federal Petitioner 5, n. 5.Respondent's fallback position from its "plain language" argument is that the phrase "general business" in § 81 at least refers to all activities in which Congress has specifically authorized a national bank to engage, including the trading in securities that the McFadden Act authorized by the amendment of 12 U.S.C. § 24 Seventh.  See McFadden Act, ch. 191, § 2, 44 Stat. 1226.  However, petitioner Security Pacific has provided a counter-example to this general thesis:  In § 2(b) of the McFadden Act, Congress specifically authorized national banks' involvement in the safe-deposit business, and in doing so deleted language from the bill that arguably would have limited the bank's authority "to conduct a safe deposit business" to activities "located on or adjacent to the premises of such association."  67 Cong.Rec. 3231 (1926).  In floor debates, Representative McFadden, in response to the question from Representative Celler whether the bill, as amended, would permit "a safe-deposit business [to be] conducted a block away or a mile away from a national banking association," replied that the deletion of the language regarding location "removes the limitations which might be very embarrassing to an institution."  Id. at 3232. [Footnote 18]  In view of this exchange, we are not persuaded that Congress intended the locational restriction of § 81 and § 36 to reach all activities in which national banks are specifically authorized to engage. Page 479 U. S. 407Respondent also relies on the following statement, which Representative McFadden placed in the Congressional Record 10 days after the passage of the McFadden Act, while Congress was in recess:"[Section 36(f)] defines the term 'branch.'  Any place outside of or away from the main office where the bank carries on its business of receiving deposits, paying checks, lending money, or transacting any business carried on at the main office, is a branch if it is legally established under the provisions of this act."68 Cong.Rec. 5816 (1927).  We do not attach substantial weight to this statement, which Congress did not have before it in passing the McFadden Act.  As the Comptroller persuasively argues, Representative McFadden cannot be considered an impartial interpreter of the bill that bears his name, since he was not favorably disposed toward branch banking. [Footnote 19]  If we took literally Representative McFadden's view of § 36(f), we would have to conclude that Congress intended to overturn the Attorney General's opinion in Lowry National Bank, 29 Op.Atty.Gen. 81 (1911), which this Court had previously approved in First National Bank in St. Louis v. Missouri, supra, at  263 U. S. 658.  Congress never specifically indicated such an intention, and we find it hard to imagine that it would have made such a change without comment.It is significant that, in passing the McFadden Act, Congress recognized and for the first time specifically authorized the practice of national banks' engaging in the buying and selling of investment securities.  See Act of Feb. 25, 1927, ch. 191, § 2, 44 Stat. 1226. [Footnote 20]  Prior to 1927, banks had conducted Page 479 U. S. 408 such securities transactions on a widespread and often interstate basis, without regard to the locational restriction imposed by § 5190 on "the usual business of each national banking association."  See, e.g., W. Peach, The Security Affiliates of National Banks 74 (1941); Perkins, The Divorce of Commercial and Investment Banking:  A History, 88 Banking L.J. 483, 492, 494, n. 26 (1971). [Footnote 21]  We find it unlikely that Congress, in recognizing and explicitly authorizing this practice, would have undertaken to limit its geographic scope through the branching law without specifically noting the restriction on the prior practice. [Footnote 22] Page 479 U. S. 409For the foregoing reasons, we conclude that Congress did not intend to subject a bank's conduct of a securities business to the branching restrictions imposed by 12 U.S.C. § 36(f).  We do not view our decision today as inconsistent with our prior decisions interpreting 12 U.S.C. § 36(f) as embodying a policy of "competitive equality" between state and national banks.  See, e.g., First National Bank in Plant City v. Dickinson, 396 U. S. 122 (1969).  The Comptroller reasonably interprets the statute as requiring "competitive equality" only in core banking functions, and not in all incidental services in which national banks are authorized to engage. [Footnote 23]  We are not faced today with the need to decide whether there are core banking functions beyond those explicitly enumerated in § 36(f); it suffices, to decide this case, to hold that the operation of a discount brokerage service is not a core banking function.Accordingly, the judgment of the Court of Appeals is affirmed insofar as it held that respondent has standing, and reversed on the merits.It is so ordered
U.S. Supreme CourtClarke v. Securities Indus. Ass'n, 479 U.S. 388 (1987)Clarke v. Securities Industry AssociationNo. 85-971Argued November 3, 1986Decided January 14, 1987479 U.S. 388SyllabusPetitioner Security Pacific National Bank (Security Pacific) applied to the Comptroller of the Currency for permission to establish an affiliate named Discount Brokerage, and to offer discount brokerage services not only at its branch offices but also at other locations inside and outside of its home State.  A pertinent branching provision of the National Bank Act, 12 U.S.C. § 81, originally enacted in 1927 as part of the McFadden Act, limits "the general business" of a national bank to its headquarters and any "branches" permitted by 12 U.S.C. § 36.  Section 36(c) provides that a national bank is permitted to branch only in its home State, and only to the extent that a bank of the same State is permitted to branch under state law, and the term "branch" is defined in § 36(f)"to include any branch bank, branch office, branch agency, additional office or any branch place of business . . . at which deposits are received, or checks paid, or money lent."The Comptroller approved Security Pacific's application, concluding that the nonchartered offices at which Discount Brokerage would offer its services would not constitute branches under the McFadden Act because none of the statutory branching functions set forth in § 36(f) would be performed there, and that treating offices conducting brokerage activities as branches under § 36(f) would be inconsistent with the longstanding practice of banks in operating nonbranch offices dealing in United States Government or municipal securities.  Respondent, a trade association representing securities brokers, underwriters, and investment bankers, brought suit in Federal District Court, contending that bank discount brokerage offices are branches within the meaning of § 36(f), and thus are subject to the geographical restrictions imposed by § 36(c).  The court, relying on Association of Data Processing Service Organizations, Inc. v. Camp, 397 U. S. 150, rejected the Comptroller's contention that respondent lacked standing to maintain the action, and ruled for respondent on the merits.  The Court of Appeals affirmed. Page 479 U. S. 389Held:1. Respondent has standing to maintain this lawsuit.  Under the "standing" standard set forth in Association of Data Processing Service Organizations, supra, at 153, the complainant must be injured in fact, and the interest sought to be protected by the complainant must be arguably within the "zone of interests" to be protected or regulated by the statute in question.  The essential inquiry in determining standing is whether Congress intended for a particular class of plaintiffs to be relied upon to challenge an agency's disregard of the law.  Cf. Block v. Community Nutrition Institute, 467 U. S. 340,  467 U. S. 347.  The "zone of interest" test provides standing in this case, since the interest respondent asserts has a plausible relationship to the policies underlying §§ 36 and 81 with regard to Congress' concern to keep national banks from gaining a monopoly control over credit and money through unlimited branching.  Pp.  479 U. S. 394-403.2. The Comptroller, whose construction of the statutory provisions is entitled to great weight, did not exceed his authority in approving Security Pacific's application.  There is no merit to respondent's contention that the Comptroller's interpretation of the National Bank Act contradicts the plain language of the statute.  The phrase "[t]he general business of each national banking association" in § 81 need not be read to encompass all the business in which a bank engages, but, as interpreted by the Comptroller, can plausibly be read as covering only those activities that are part of the bank's core banking functions.  The Act's history, including that predating the branching provisions of the McFadden Act, supports the Comptroller's interpretation.  The history of the McFadden Act itself does not establish that Congress intended the locational restriction of §§ 81 and 36 to reach all activities in which national banks are specifically authorized to engage.  The Comptroller reasonably interprets § 36(f) as requiring "competitive equality" between state and national banks only in core banking functions, and the operation of a discount brokerage service is not such a function.  Pp.  479 U. S. 403-409.244 U.S.App.D.C. 419, 758 F.2d 739, and 247 U.S.App.D.C. 42, 765 F.2d 1196, affirmed in part and reversed in part.WHITE, J., delivered the opinion of the Court, in which BRENNAN, MARSHALL, BLACKMUN, and POWELL, JJ., joined, and in Parts I and III of which REHNQUIST, C. J., and STEVENS and O'cONNOR, JJ., joined.  STEVENS, J., filed an opinion concurring in part and concurring in the judgment, in which REHNQUIST, C.J., and O'CONNOR, J., joined, post, p.  479 U. S. 409.  SCALIA, J., took no part in the consideration or decision of the cases. Page 479 U. S. 390