Amicus Curiae Brief — Real Estate Exchange, Inc., a Delaware Corporation, Petitioner v. Zillow Group, Inc., a Washington Corporation, et al.

No. 25-326

In the

Supreme Court of the United States

__________________________________________

REAL ESTATE EXCHANGE, INC.,

Petitioner,

v.

ZILLOW GROUP, INC. AND

NATIONAL ASSOCIATION OF REALTORS,

Respondents.

__________________________________________

On Petition for Writ of Certiorari

to the United States Court of Appeals

for the Ninth Circuit

__________________________________________

BRIEF OF AMICUS CURIAE

ANTITRUST EDUCATION PROJECT

IN SUPPORT OF PETITIONER

__________________________________________

DAVID H. THOMPSON

Counsel of Record

HAROLD S. REEVES

COOPER & KIRK, PLLC

1523 New Hampshire

Avenue, N.W.

Washington, D.C. 20036

(202) 220-9600

dthompson@cooperkirk.com

Counsel for Amicus Curiae

October 14, 2025

i

TABLE OF CONTENTS

Page

TABLE OF AUTHORITIES ....................................... ii

INTEREST OF AMICUS CURIAE............................. 1

SUMMARY OF THE ARGUMENT ............................ 2

ARGUMENT ............................................................... 3

I. The Ninth Circuit Erroneously Concluded That

An Agreement To Adopt A Non-Binding Rule Is

Not An Agreement Under The Sherman Act. ....... 3

A. Even An Agreement To Adopt An Optional

Rule Is An Agreement. ..................................... 5

B. Even An Optional Rule May Invite Competitors to Take Concerted Action. ......................... 7

II. The Ninth Circuit Decision Would Harm

Consumer Welfare. ................................................ 8

A. The Sherman Act Protects Competition To

Protect Consumers. .......................................... 8

B. The Decision Below Contradicts The

Consumer Welfare Standard.......................... 13

CONCLUSION .......................................................... 19

ii

TABLE OF AUTHORITIES

CASES

Page(s)

American Needle, Inc. v. Nat’l Football League,

560 U.S. 183 (2010)............................. 4, 6, 7, 16

Brunswick Corp. v. Pueblo Bowl–O–Mat, Inc.,

429 U.S. 477 (1977)................................... 10, 11

Business Electronics Corp. v. Sharp Electronics

Corp., 485 U.S. 717 (1988).............................. 16

Continental T.V., Inc. v. GTE Sylvania, Inc.,

433 U.S. 36 (1977) .......................................... 16

Gamco Inc. v. Providence Fruit & Produce Bldg,

194 F.2d 484 (1st Cir. 1952) ........................... 17

In re High Fructose Corn Syrup Antitrust Litig.,

295 F.3d 651 (7th Cir. 2002) ............................ 7

Leegin Creative Leather Prods., Inc. v. PSKS, Inc.,

551 U.S. 877 (2007)......................................... 11

Marrese v. Am. Acad. of Orthopaedic Surgeons,

706 F.2d 1488 (7th Cir. 1983) ........................ 18

Monsanto v. Spray-Rite Serv. Corp.,

465 U.S. 752 (1984)........................................... 7

National Soc’y of Pro. Eng’rs v. United States,

435 U. S. 679 (1978).......................................... 7

Novell, Inc. v. Microsoft Corp.,

731 F.3d 1064 (10th Cir. 2013) ................ 11, 12

Ohio v. Am. Express Co.,

585 U.S. 529 (2018)......................................... 11

Olympia Equip. Leasing Co. v. W. Union Tel. Co.,

797 F.2d 370 (7th Cir. 1986) .......................... 10

iii

Real Estate Exchange Inc. v. Zillow Group, Inc.,

No. 24-685, 2025 WL 670967

(9th Cir. Mar. 3, 2025) ...................................... 1

Reiter v. Sonotone Corp.,

442 U.S. 330 (1979)........................................... 9

United States v. Aluminum Co. of Am.,

148 F.2d 416 (2d Cir. 1945) .......................... 8, 9

United States v. Am. Tobacco Co.,

221 U.S. 1063 (1911)....................................... 16

United States v. Gen. Motors Corp.,

384 U.S. 127 (1966)......................................... 16

United States v. Grinnell Corp.,

384 U.S. 563 (1966)......................................... 12

United States v. New Wrinkle, Inc.,

342 U.S. 371 (1952)......................................... 16

United States v. Sealy, Inc.,

388 U.S. 350 (1967)......................................... 16

United States v. Sw. Greyhound Lines, Inc.,

1953 Trade Cases ¶ 67,470, 1953 WL 100908

(N.D. Okla. Mar. 27, 1953) ............................. 17

United States v. Terminal R.R. Ass’n of St. Louis,

224 U.S. 383 (1912)................................... 16, 17

United States v. Trans-Missouri Freight Ass’n,

166 U.S. 290 (1897)........................................... 8

CODES

15 U.S.C. § 1 ............................................................ 4, 5

iv

OTHER AUTHORITIES

Robert H. Bork, Legislative Intent and The Policy of

The Sherman Act, 9 J. L. & ECON. 7

(1966)........................................................... 9, 10

ROBERT H. BORK, THE ANTITRUST PARADOX

(1978)............................................... 9, 10, 17, 18

Composition, NAT’L ASS’N OF REALTORS,

https://perma.cc/RPB5-WJ57 ........................... 6

Veronica Dagher, Almost No One Pay a 6% Real-Estate Commission—Except Americans: How the

rest of the world buys and sells homes explained, in three charts, WALL ST. J. (Nov. 16,

2023), https://perma.cc/CZA7-3D2P ......... 14, 15

Einer Elhauge, Tying, Bundled Discounts, and the

Death of the Single Monopoly Profit Theory,

123 HARV. L. REV. 399 (2009) ........................... 9

Hon. Douglas H. Ginsburg, Wither The Consumer Welfare Standard?, 46 HARV. J. L. &

PUB. POL'Y 69 (2023) ....................................... 12

Property 118.com News Team, Global Estate Agent

Commission Comparison, PROPERTY118 (Aug.

26, 2020),

https://perma.cc/FPA8-CQZC ................... 14, 15

When Is a Real Estate Agent a REALTOR®?, NAT’L

ASS’N OF REALTORS, https://perma.cc/3GQL2G4Y.................................................................. 6

1

INTEREST OF THE AMICUS 1

Amicus, the Antitrust Education Project, is supporting the Petitioner in asking that this Court grant

certiorari to review and reverse the decision of the

Ninth Circuit in Real Estate Exchange Inc. v. Zillow

Group, Inc., No. 24-685, 2025 WL 670967 (9th Cir.

Mar. 3, 2025), insofar as that decision upheld the

lower court’s decision holding that an agreement to

impose a non-binding rule cannot constitute an agreement under Section 1 of the Sherman Act. The decision, which deepens a split among the Circuit Courts

of Appeals, departs from settled antitrust jurisprudence and in particular from the consumer welfare

standard. The Antitrust Education Project is an organization committed to combatting the rising politicization and concomitant deterioration of antitrust

theory, jurisprudence, and enforcement practices by

advocating that the consumer welfare standard

should continue to serve as the centerpiece concept of

American antitrust jurisprudence. The Project promotes education of the current generation of American law students, practitioners, and jurists about the

consumer welfare standard, and advocates for the vigorous application of that standard by the enforcement

agencies and by the courts.

1 Pursuant to SUP. CT. R. 37.6, amicus certifies that no

counsel for any party authored this brief in whole or in part, no

party or party’s counsel made a monetary contribution to fund

its preparation or submission, and no person other than amicus

or his counsel made such a monetary contribution. Pursuant to

SUP. CT. R. 37.2, notice of intent to file this brief was provided to

counsel for the parties by the Antitrust Education Project on October 2, 2025.

2

SUMMARY OF ARGUMENT

There is today a marked absence of free and open

competition in the market for real estate services.

Americans directly experience it whenever they buy

or sell a home. Everyone pays the price in the form of

higher costs, decreased output of new houses, fewer

jobs in the construction and durable goods sectors,

and the social costs of delayed family formation, that

are the inevitable result of the exorbitant commissions and fees that these gatekeepers of the American

dream extract from those seeking to acquire a home of

their own. The suppression of new entry and the prevention of innovative disruption by the National Association of Realtors (“NAR”) has benefitted only its

1.4 million members who, insulated from competition,

have continued to charge supra-competitive prices for

service that can charitably be described as a lackluster relic of the pre-Internet era.

A combination of legal errors committed below has

permitted this patent violation of the Sherman Act to

continue. First, the court held that competitors do not

enter into an agreement for purposes of Section 1 of

the Sherman Act if they agree to impose only a nonbinding rule, thereby falling into the error of confusing the question of an agreement’s existence with the

question of its efficacy; this has deepened an existing

circuit split between the Ninth and Tenth Circuits, on

the one hand, and the First, Third, and Fifth Circuits

on the other. Second, the court ignored that, by subsequently accepting an invitation to join an agreement, a party may become a party to that agreement.

Here, there is no circuit split, only clear error.

3

This Court should grant the petition for certiorari,

however, not merely to correct these errors and resolve the split between the Circuits, but also, and far

more importantly, to affirm the continuing vitality of

the consumer welfare standard that has guided the

antitrust enterprise for the past half century. The

case presents a fitting opportunity to do so not only

because of the central role that the housing industry

plays in the life of our nation, but also given that the

decision below presents a textbook example of a court

falling into error by seeking to protect competitors rather than consumers, and stifling innovation and new

entry in order to shelter legacy market participants.

Ever growing numbers of lawyers and legal scholars are urging the courts to abandon the consumer

welfare standard and succumb to the old temptation

to transform the magna carta of American competition into a tool for the advancement of idiosyncratic

ideological aims and the enforcement of individual

preferences. This petition presents the court with the

opportunity to put a definitive halt to this effort and

restore consumer welfare to its rightful place as the

lodestar of the American antitrust enterprise. The

Court should therefore grant the petition for certiorari

and reverse the decision of the Ninth Circuit.

ARGUMENT

I.

The Ninth Circuit Erroneously Concluded That An Agreement To Adopt A

Non-Binding Rule Is Not An Agreement

Under The Sherman Act.

Section 1 of the Sherman Act prohibits every “contract, combination * * * or conspiracy” that

4

unreasonably restrains trade. 15 U.S.C. § 1. “The

question whether an arrangement is a contract, combination, or conspiracy is different from and antecedent to the question whether it unreasonably restrains

trade.” American Needle, Inc. v. Nat’l Football League,

560 U.S. 183, 186 (2010). To constitute a Section 1 contract, combination, or conspiracy, an arrangement

must be (a) an agreement (b) between two or more entities capable of engaging in concerted action. Id. at

189–190. If there has been no such agreement, then

there has been no concerted action. But wherever

competitors have agreed to adopt rules, guidelines, or

standards, then their “activities constitute concerned

action that is not categorically beyond the coverage of

§ 1.” Id. at 186. And “the legality of that concerted

action must be judged under the Rule of Reason.” Id.

The Ninth Circuit’s ruling that the agreement by

the members realtors of the NAR to adopt the Segregation Rule is not an agreement because that rule is

“optional” ignores two of the three ways in which this

Court has acknowledged that even an optional rule

may violate the antitrust laws: first, where members

of an association are competitors and either participate in the adoption of the rule or have delegated the

authority to adopt and promulgate the rule to the association, the adoption of the rule itself constitutes

concerted action that is subject to antitrust scrutiny;

and, second, where the optional rule invites the members of an association to agree to adopt and enforce the

“optional” standard, and the members signal their

agreement by so doing.

5

A.

Even An Agreement to Adopt an

Optional Rule is an Agreement.

Both the District Court and Court of Appeals

erred by holding that the Segregation Rule was not

the product of an agreement because it “is entirely optional and has not been adopted by approximately

29% of NAR-affiliated MLSs.” Pet.App.29a; See also

id. at 3a (“The rule was in fact optional and does not

establish a Section 1 agreement by itself.”). This is

wrong under settled precedent and as a matter of simple common sense insofar as it overlooks that the

adoption of the optional rule was itself the product of

an agreement among competitors and thus was,

standing alone, concerted action.

The adoption of the Segregation Rule constituted

concerted action for purposes of Section 1 because a

decision by the NAR board of directors reflects concerted action on the part of competitors. As this Court

explained in American Needle, Inc. v. National Football League, the inquiry into whether there has been

concerted action looks to whether there has been an

agreement that deprives the marketplace of independent centers of decisionmaking:

The key is whether the alleged contract, combination, or conspiracy is concerted action—that is, whether it joins

together separate decisionmakers. The

relevant inquiry, therefore, is whether

there is a contract, combination, or conspiracy amongst separate economic actors pursuing separate economic interests, such that the agreement deprives

the marketplace of independent centers

6

of decisionmaking, and therefore of diversity of entrepreneurial interests, and

thus of actual or potential competition.

560 U.S. at 195 (cleaned up). The membership of the

NAR board of directors includes competitors in the industry, including individual REALTORS® 2 and representatives from each of the 75 largest real estate

firms. 3 The decision by the NAR to adopt even an optional rule, therefore, itself reflected “concerted action

under Section 1 that joins together separate decisionmakers” in the formulation of an agreed upon result.

This is not to say that an optional rule or discretionary standard is indistinguishable from a mandatory or binding one. The optional nature of the rule

likely mitigates the quantum of its anticompetitive effect. It does not, however, alter the fact that the decision to adopt the rule was concerted action under Section 1. Competitors can agree to compete vigorously

and, while it is hard to imagine how such an agreement would fail to pass survive scrutiny under the

Rule of Reason, it would nevertheless constitute concerted action under the Sherman Act. A non-binding

rule or standard may impose less of a restraint on

2 A REALTOR® is defined by the NAR as “a member of NAR,

National Association of REALTORS® as well as a licensed real

estate professional. … a REALTOR® pledges to uphold integrity,

honesty, and client interests through NAR Code of Ethics and

complete ethics training every three years.” When Is a Real Estate Agent a REALTOR®?, NAT’L ASS’N OF REALTORS,

https://perma.cc/3GQL-2G4Y.

Composition,

NAT’L

https://perma.cc/RPB5-WJ57.

3

ASS’N

OF

REALTORS,

7

competition than a mandatory one. But an agreement

to adopt a non-binding rule or standard is no less an

agreement than one to adopt one that is mandatory

and binding. In short, the court below fell into the

trap identified by Judge Posner of “failing to distinguish between the existence of a conspiracy and its efficacy.” In re High Fructose Corn Syrup Antitrust

Litig., 295 F.3d 651, 656 (7th Cir. 2002). 4

B.

Even An Optional Rule May Invite

Competitors to Take Concerted Action.

The second error below was the assumption

shared by the district court and the court of appeals

4 A failure to distinguish between unilateral and concerted

action may have contributed to the making of this error. Indeed,

both the Ninth Circuit and, before it the Tenth Circuit, effectively applied the standard that is used when a manufacturer

unilaterally announces a suggested price or policy, in which case

there is no concerted action but only the unilateral action of the

manufacturer, to analyze an agreement by competitors, acting as

members of a trade association, to announce a suggested rule, in

which case there is an agreement, made when those competitors

agree to the adoption of the optional rule.

In the former case, the manufacturer is free to suggest and

even to enforce whatever price or policy it prefers, for as this

Court has made clear, such “[i]ndependent action is not proscribed. A manufacturer of course generally has a right to deal,

or refuse to deal, with whomever it likes, as long as it does so

independently.” Monsanto v. Spray-Rite Serv. Corp., 465 U.S.

752, 761 (1984) (citing United States v. Colgate & Co., 250 U.S.

300, 307 (1919)). In the latter case, however, the action of the

trade association members is analyzed using the rule of reason.

National Soc’y of Pro. Eng’rs v. United States, 435 U. S. 679, 687–

92, 697 (1978) (prohibiting the Society from adopting any “opinion, policy statement, or guideline stating or implying that competitive bidding is unethical”).

8

that, where a defendant was not an original party to

the agreement to promulgate a non-binding rule, its

subsequent decision to adopt the rule to which the

original conspirators agreed cannot form the basis for

§ 1 liability. One need not get in on the ground floor

to be held liable under § 1. Nor does a defendant who

subsequently agrees to adopt and adhere to an existing restraint of trade immunized from liability by the

fact that it chose to do so freely. Indeed, it would be

perverse if one could be held liable for choosing to join

an agreement only if one in fact had no choice but to

do so.

II. The Ninth Circuit Decision Would Harm

Consumer Welfare.

A. The Sherman Act Protects Competition

To Protect Consumers.

Antitrust jurisprudence once reflected a raft of

subjective biases and idealized visions of commerce

that had little grounding in economics, tended to punish reasonable business arrangements, promoted inefficiency, and thwarted the basic purposes of the antitrust laws; namely, the promotion of the well-being

of the American consumer. Indeed, for the first half

of the last century, the focus of American antitrust

policy and enforcement remained the protection of

“small dealers and worthy men,” United States v.

Trans-Missouri Freight Ass’n, 166 U.S. 290, 323

(1897), against competition from larger, more efficient

enterprises. Untethered from the original purpose of

the Sherman Act, the courts came to prefer, on account of its “social and moral” effects, “a system of

small producers, each dependent for his success upon

his own skill and character, to one in which the great

9

mass of those engaged must accept the direction of a

few.” United States v. Aluminum Co. of Am., 148 F.2d

416, 427 (2d Cir. 1945) (Hand, J.). This effort to combat the “curse of bigness” continued well into the

1970s.

The courts have now accepted that “Congress designed the Sherman Act as a ‘consumer welfare prescription.”’ Reiter v. Sonotone Corp., 442 U.S. 330, 343

(1979) (quoting ROBERT H. BORK, THE ANTITRUST PARADOX 66 (1978)). 5 The recovery of the Sherman Act’s

original meaning and the restoration of the antitrust

laws to the service of their intended purpose owes

much to the efforts of Judge Robert H. Bork, who argued persuasively that “[t]he whole task of antitrust

can be summed up as the effort to improve allocative

efficiency without impairing productive efficiency so

greatly as to produce either no gain or a net loss in

consumer welfare.” 6 Judge Bork established that the

overriding purpose of the antitrust laws is to enhance

“consumer welfare,” that is, the “maximization of

wealth or consumer want satisfaction.” 7 And to

achieve that end, the Congress intended for the courts

to focus on the task of “distinguish[ing] between

agreements or activities that increase wealth through

5 See, e.g., Robert H. Bork, Legislative Intent and The Policy

of The Sherman Act, 9 J. L. & ECON. 7 (1966); Einer Elhauge,

Tying, Bundled Discounts, and the Death of the Single Monopoly

Profit Theory, 123 HARV. L. REV. 399, 435–42 (2009) (showing

that case law, legislative history and sound policy all support a

consumer welfare standard).

6 BORK, THE ANTITRUST PARADOX, supra, at 91.

7 Bork, Legislative Intent, supra, at 7.

10

efficiency and those that decrease it through restriction of output.” 8

Antitrust “has a built-in preference for material

prosperity, but it has nothing to say about the ways

prosperity is distributed or used.” 9 But there is “not a

scintilla of support”' in the Sherman Act’s legislative

history for “broad social, political, and ethical mandates.” 10 “Consumer welfare,” properly understood,

thus includes the maximizing of economic efficiency

but excludes anything having to do with the fairness

of commercial transactions and economic transfers, or

with achieving a just distribution of wealth and economic power.

Beginning in the 1970s, this originalist understanding of the Sherman Act gained widespread acceptance and the aim of antitrust scrutiny has progressively shifted from the “protection of competition

as a process of rivalry to the protection of competition

as a means of promoting economic efficiency.” Olympia Equip. Leasing Co. v. W. Union Tel. Co., 797 F.2d

370, 375 (7th Cir. 1986) (Posner, J.). The focus of the

analysis remains on protecting competition, not competitors. Brunswick Corp. v. Pueblo Bowl–O–Mat,

8 Id.

9 BORK, THE ANTITRUST PARADOX, supra, at 90; See also id.

at 111 (“[I]t seems clear the income distribution effects of economic activity should be completely excluded from the determination of the antitrust legality of the activity. It may be sufficient

to note that the shift in income distribution does not lessen total

wealth, and a decision about it requires a choice between two

groups of consumers that should be made by the legislature rather than by the judiciary.”).

10 Bork, Legislative Intent, supra, at 10.

11

Inc., 429 U.S. 477, 488 (1977) (“The antitrust laws ...

were enacted for ‘the protection of competition, not

competitors.’ ” (quoting Brown Shoe Co. v. United

States, 370 U.S. 294, 320 (1962))). But the effect of a

restraint on competition is analyzed specifically “with

the interests of consumers, not competitors, in mind.”

Novell, Inc. v. Microsoft Corp., 731 F.3d 1064, 1072

(10th Cir. 2013) (Gorsuch, J.). The aim, in other

words, is to “distinguish[] between restraints with anticompetitive effect that are harmful to the consumer

and restraints stimulating competition that are in the

consumer’s best interest.” Leegin Creative Leather

Prods., Inc. v. PSKS, Inc., 551 U.S. 877, 886 (2007);

Accord Ohio v. Am. Express Co., 585 U.S. 529, 541

(2018).

Antitrust is today no longer a tool for the imposition by the judiciary of ideological and aesthetic preferences on the free market. The futile struggle to promote the small over the big and to sort the worthy

from the unworthy has ended, replaced by a focus on

promoting innovation, raising output, lowering prices,

and broadening consumer choice, all to be achieved by

fostering free and open competition. The innovation,

growth, and rising living standards that have characterized the past 45 years bear eloquent witness to the

long-lasting, positive impact of the antitrust revolution ushered in by the Judge Bork and the proponents

of the Chicago School.

The price of economic prosperity remains eternal

judicial vigilance. Today, there are voices on both the

left and right calling for a return to the mistakes of

the past. The cry is again raised in favor of embracing

more sweeping standards that would serve social and

12

moral agenda, aims that lie entirely outside the purview of the antitrust laws. 11 Again, the nation’s successful and most innovative companies find themselves under attack solely because of their innovation

and success, either because they have become too big

for the tastes of the hipster antitrust movement or

have transgressed the political preferences of the antitrust enforcers. Again, there are those who seek to

use the competition laws to promote the personal and

political rather than efficiency, innovation, and consumer welfare.

If the original intention of the Congress that enacted the Sherman Act is to be respected, then the

consumer welfare standard must remain the lodestar

by which the antitrust enterprise is conducted. For it

is the consumer welfare standard that permits the enforcers and the courts alike to distinguish between

bigness that is the fruit of anticompetitive conduct or

that is being abused to restrain competition, thwart

efficiency, and harm the consumer, and bigness that

is merely the consequence “of a superior product,

business acumen, or historic accident.” United States

v. Grinnell Corp., 384 U.S. 563, 570–71 (1966). It is

only by looking to efficiency, price, and innovation,

and not to diversity, equity, and inclusion, that the

courts will ensure that the antitrust laws are not diverted into the service of the prevailing predilections

of the day but continue to serve their original purpose

of promoting competition and benefitting the American consumer.

See, e.g., Hon. Douglas H. Ginsburg, Wither The Consumer Welfare Standard?, 46 HARV. J. L. & PUB. POL'Y 69, 72–81

(2023).

11

13

B. The Decision Below Contradicts The Consumer Welfare Standard.

The Ninth Circuit has joined the Tenth Circuit in

creating a safe harbor in which those competitors who

seek to restrain competition and inflict harm on consumers may find unfailing shelter from antitrust scrutiny. The standard they have announced would license competitors to restrain competition whenever

competition can be restrained by means of a non-binding rule, standard, or guideline. It is not merely that

such agreements would survive antitrust scrutiny under this standard; they would not be subject to antitrust scrutiny at all. And where, as here, that nonbinding rule suffices to protect inefficient incumbents

against competition from new entrants, it is the consumer who will suffer the harms lower quality service,

reduced choice, and higher prices, fees, and commissions.

On its face, the NAR’s Segregation Rule purports

merely to separate the MLS listings offered by members of the NAR from the non-MLS listings offered by

realtors who are not members. In its effect, however,

the rule resulted in the listings offered by new entrants being made invisible to consumers. After Zillow agreed to comply with the NAR’s Segregation Rule

and redesigned its website to separate listings from

non-NAR realtors, Consumer traffic to the new entrant’s website plummeted by 90 percent. That new

entrant, Petitioner Real Estate Exchange, was forced

out of business.

The harm was not merely to these competitors, of

course, but to competition and to consumers as well.

The facts and the data speak for themselves. Realtors

14

continue to extract six percent of every real estate

transaction that takes place in the United States, a

figure that has remained constant for over half a century, even as buyers have come use the Internet to

perform most of the work that once would have required the use of a buyer’s agent, and even as house

prices have experienced inflation far in excess of the

rate at which wages have increased. 12 As a 2020

study revealed, the stifling of competition in the market for realtor services has resulted in Americans now

paying more, substantially more, when they buy or

sell their home than their counterparts in other developed countries: 13

Country

Average

Commission

US

Australia

Canada

New Zealand

Argentina

Israel

France

6%

5.7%

5%

4.3%

4.2%

4%

3.9%

12 Veronica Dagher, Almost No One Pay a 6% Real-Estate

Commission—Except Americans: How the rest of the world buys

and sells homes explained, in three charts, WALL ST. J. (Nov. 16,

2023), https://perma.cc/CZA7-3D2P (“In the pre-internet days, a

buyer agent’s main job was to screen and filter listings for hopeful home buyers. Today, much of that early house hunting can be

done online.”).

13 Property 118.com News Team, Global Estate Agent Com-

mission Comparison, PROPERTY118

https://perma.cc/FPA8-CQZC.

(Aug.

26,

2020),

15

Italy

Japan

Spain

Germany

UK

China

Singapore

Netherlands

Hong Kong

South Korea

3.4%

3.15%

2.75%

2.7%

1.8%

1.75%

1.5%

1.5%

0.75%

0.55%

Id. The Wall Street Journal reported in 2023 that

even consumers in Russia (3.5%) and Red China

(2.5%) pay substantially less when they buy and sell

their homes than American consumers. 14

The members of the NAR were able to agree

upon a mechanism that would prevent a new entrant

introducing price competition into this market. What

is more, they were able to immunize their agreement

from scrutiny by devising a restraint that, while

highly effective at barring that new entry, was formally optional and non-binding. They were able to do

this because the analysis embraced by the Ninth Circuit unavoidably turns a blind eye to the actual and

demonstrable economic effects of a restraint so long as

the parties characterize the restraint as optional. An

agreement that restrains competition in practice will

pass muster, therefore, so long as it might not have

restrained competition in theory. This represents the

14 Dagher, supra at n.11.

16

triumph of form over substance and, more importantly, over competition.

The Ninth Circuit’s decision thus ignores this

court’s oft-repeated injunction to “seek the central

substance of the situation, not its periphery,” when

analyzing the effect of a restraint on competition.

United States v. Sealy, Inc., 388 U.S. 350, 353 (1967);

See also American Needle, Inc., 560 U.S. at 191–92;

Timken Roller Bearing Co. v. United States, 341 U.S.

593 (1951); United States v. Gen. Motors Corp., 384

U.S. 127 (1966); United States v. New Wrinkle, Inc.,

342 U.S. 371 (1952); United States v. Am. Tobacco Co.,

221 U.S. 1063 (1911). Indeed, as this Court has repeatedly affirmed, the analysis under the antitrust

laws is concerned not with the formalities competitors

use to enter their agreement to restrain trade, but

with the “demonstrable economic effect” that the restraint has in practice. Continental T.V., Inc. v. GTE

Sylvania, Inc., 433 U.S. 36, 58–59 (1977); See also

Business Electronics Corp. v. Sharp Electronics Corp.,

485 U.S. 717, 724 (1988). For it is only by keeping the

focus of the analysis squarely on those demonstrable

economic effects that the courts can ensure that consumers are receiving the benefits of the competition

the Sherman Act protects.

Had the courts below subjected it to scrutiny under the rule of reason, they would have found that,

although formally non-binding, the NAR’s Segregation Rule was in terms of its demonstrable economic

effects indistinguishable from a predatory group boycott undertaken to deny market access to a new entrant threatening to introduce technological innovation and competition. The courts have long recognized

17

the anticompetitive effects of such boycotts and have

condemned them, even when compliance with them

was formally optional, as antithetical to the Sherman

Act. See, e.g., United States v. Terminal R.R. Ass’n of

St. Louis, 224 U.S. 383, 409-410 (1912) (condemning

use of control exercised over existing approaches to

river crossing to exclude competitors); Gamco Inc. v.

Providence Fruit & Produce Bldg, 194 F.2d 484, 487–

89 (1st Cir. 1952) (condemning coordinated refusal to

renew lease to competitor); United States v. Sw. Greyhound Lines, Inc., 1953 Trade Cases ¶ 67,470, 1953

WL 100908 (N.D. Okla. Mar. 27, 1953) (competitors’

actions resulting in tenant who refused to cease competing with them being evicted from main bus terminal violated both § 1 and § 2 of Sherman Act). Indeed,

as Judge Bork observed, these sorts of “predatory boycotts engaged in by members of a joint venture are relatively easy to spot.” 15 It would have been easy to spot

here, as well, had the Ninth Circuit not adopted a rule

that requires the courts to close their eyes.

It is a rule, moreover, that appears to have resuscitated the long-discredited preference for the small,

inefficient, legacy merchants. There may be reasons

why the legacy realtors now working in the United

States need to be sheltered from change, from innovation, and from free and open competition. As Judge

Bork observed nearly half a century ago, it is not for

the courts, but for the legislature, to decide if and

when the American consumer is to bear the cost of

15 BORK, THE ANTITRUST PARADOX, supra, at 336–37 (observ-

ing that court in Southwestern Greyhound “had no difficulty in

perceiving the connection between the evicted tenant’s increased

competition and the eviction”).

18

shielding an inefficient form of commerce from competition:

Courts are the wrong institution for

these unstructured interpersonal comparisons both because political choices of

this nature should, in a society with our

presuppositions about democracy, be

made by elected and representative institutions, and because the courts do not

have the facilities for fact-finding on a

broad scale that are available to the legislature. The admission by a court of

goals in conflict with the consumer welfare into the adjudicative process, therefore, involves a serious usurpation of the

legislative function by the judicial arm. 16

If realtors alone, unlike stock brokers, bookstore

owners, and mom-and-pop groceries, are to be excluded from the reach of the antitrust laws and protected from the sort of disruption the Internet has introduced into these other sectors or our economy, it is

for Congress, the branch of government most directly

answerable to the individual American consumer who

would pay the price for that decision, to grant that exemption.

BORK, THE ANTITRUST PARADOX, supra, at 83; See also

Marrese v. Am. Acad. of Orthopaedic Surgeons, 706 F.2d 1488,

1497 (7th Cir. 1983) (“[A] consumer has no interest in the preservation of a fixed number of competitors greater than the number

required to assure his being able to buy at the competitive

price.”) (Posner, J.).

16

19

CONCLUSION

This Court should grant the petition for certiorari,

reverse the decision of the Ninth Circuit, and reaffirm

that the Sherman Act was enacted as a prescription

for consumer welfare.

October 14, 2025

Respectfully submitted,

DAVID H. THOMPSON

Counsel of Record

HAROLD S. REEVES

COOPER & KIRK, PLLC

1523 New Hampshire

Avenue, N.W.

Washington, D.C. 20036

(202) 220-9600

dthompson@cooperkirk.com

Counsel for Amicus Curiae