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beginning of this opinion is the date the opinion was
released as a slip opinion. The operative date for the
beginning of all time periods for filing postopinion
motions and petitions for certification is the ‘‘officially
released’’ date appearing in the opinion.
 This opinion is subject to revisions and editorial
changes, not of a substantive nature, and corrections
of a technical nature prior to publication in the
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       THE RESERVE REALTY, LLC, ET AL. v.
        WINDEMERE RESERVE, LLC, ET AL.
                   (SC 19979)
                   (SC 19982)
       THE RESERVE REALTY, LLC, ET AL. v.
            BLT RESERVE, LLC, ET AL.
                   (SC 19981)
           Robinson, C. J., and Palmer, McDonald, D’Auria,
                    Mullins, Kahn and Ecker, Js.
    Argued September 18, 2018—officially released March 24, 2020*

                         Procedural History

   Action, in the first case, to recover damages for, inter
alia, breach of contract, and for other relief, and actions
in the second and third cases to foreclose broker’s liens
on certain of the defendants’ real property, brought to
the Superior Court in the judicial district of Danbury,
where, in the first case, the court, Doherty, J., granted
the plaintiffs’ motion to add Century 21 Scalzo Realty,
Inc., as a defendant; thereafter, in the first case, the
plaintiffs withdrew the action as to the defendant Cen-
tury 21 Scalzo Realty, Inc., and, in the second case, the
plaintiffs withdrew the action as to the defendant The
Reserve Master Association, Inc.; subsequently, the first
case was tried to the court, Truglia, J.; judgment for
the named defendant et al., from which the plaintiffs
appealed to the Appellate Court; thereafter, in the sec-
ond and third cases, the court, Truglia, J., rendered
judgments discharging the broker’s liens in accordance
with the parties’ stipulations, and separate appeals were
filed with the Appellate Court; subsequently, the Appel-
late Court, Alvord, Sheldon and Schaller, Js., affirmed
the judgments of the trial court, and the plaintiffs, on
the granting of certification, filed separate appeals with
this court. Reversed; further proceedings.
  Daniel E. Casagrande, with whom was Lisa M.
Rivas, for the appellants (plaintiffs).
  Christopher Rooney, with whom was Brian A. Daley,
for the appellees (named defendant et al.).
                          Opinion

   ROBINSON, C. J. These certified appeals invite us to
revisit State v. Hossan-Maxwell, Inc., 181 Conn. 655,
662–63, 436 A.2d 284 (1980), in which this court held that
real estate ‘‘list-back’’ agreements—tying arrangements
that commit the purchaser of a parcel of real property
to use the services of a particular broker when leasing
or reselling the property1—are per se illegal under state
antitrust law. Specifically, we must decide whether, in
light of recent antitrust scholarship and developments
in federal tying law, Hossan-Maxwell, Inc., should be
overruled. We answer that question in the affirmative.
Accordingly, we reverse the judgments of the Appellate
Court, which, like the trial court, correctly determined
that it was required to apply Hossan-Maxwell, Inc., to
the present case.
   These appeals arise out of a breach of contract action
involving the sale and development of 546 acres of
the former Union Carbide Corporation (Union Carbide)
corporate campus in Danbury (the Reserve). The pri-
mary brokers involved in the transactions were Jeanette
Haddad (Haddad), a prominent local real estate agent
who died in 2013, and Paul P. Scalzo.2 The plaintiffs
are Haddad’s husband, Theodore Haddad, Sr., as execu-
tor of his wife’s estate, and The Reserve Realty, LLC
(Reserve Realty), a limited liability company organized
by Haddad and Scalzo to market and sell the Reserve
as it became subdivided. The defendants, BLT Reserve,
LLC (BLT), and Windemere Reserve, LLC (Windemere),
are limited liability companies, the principals and own-
ers of which include Carl R. Kuehner, Jr., and Paul J.
Kuehner, whose family is longtime friends and business
associates of the Haddad family. In this action, the
plaintiffs sought to recover real estate brokerage fees
in connection with the sale and/or lease of units in an
apartment complex constructed on the Reserve and
leased by BLT, and of commercial office space to be
constructed on the Reserve by Windemere. After a trial
to the court, judgments were rendered in favor of the
defendants. The Appellate Court affirmed, agreeing
with the trial court that the defendants’ antitrust special
defense barred the plaintiffs’ claims. Reserve Realty,
LLC v. Windemere Reserve, LLC, 174 Conn. App. 130,
132, 165 A.3d 162 (2017).
                             I
  The relevant facts, as found by the trial court or that
are undisputed, and complete procedural history are
set forth in detail in the opinion of the Appellate Court.
See id., 132–38. In brief, following its acquisition by
the Dow Chemical Company (Dow Chemical) in 1999,
Union Carbide made known that it would entertain
offers to sell the Reserve to interested buyers. Garland
Warren, then a Union Carbide employee, initially was
responsible for overseeing the sale of the parcel.
  In early 2002, a group of real estate developers, later
known as Woodland Group II, LLC (Woodland),
engaged the services of Haddad and Scalzo to represent
them in negotiations to purchase the Reserve. Wood-
land appears to have chosen Haddad and Scalzo in part
because Warren had since left Dow Chemical and been
employed by Scalzo.
  As part of the broker-client relationship, Haddad,
Scalzo, and Woodland executed an ‘‘Exclusive Right to
Sell—Listing Agreement’’ (Woodland agreement). The
Woodland agreement gave Haddad and Scalzo the
exclusive right to sell and/or lease property in the
Reserve. The agreement also contained the following
provision: ‘‘[Woodland] shall make aware to the new
purchaser of any part, or of individual lots, or of land,
that this [a]greement shall apply to that new purchaser
and [Haddad and Scalzo].’’
  Woodland succeeded in purchasing the Reserve, and
the plaintiffs received a commission for facilitating that
sale. Woodland subsequently proposed a master plan
for the entire 546 acre parcel, which the Danbury Zoning
Commission approved in November, 2002. Woodland
then continued to use the services of Haddad and Scalzo
to market the property to potential buyers.
  Efforts to develop the property foundered, however,
when Windemere, which was in the process of devel-
oping a neighboring parcel of land, appealed Wood-
land’s zoning approval for the Reserve, effectively
blocking development of the land. To resolve the zoning
dispute, Woodland agreed to sell one portion of the
Reserve (parcel 13) to BLT for residential development
(a luxury apartment complex, Abbey Woods, had been
built at the time of trial), and another portion (parcel
15) to Windemere for commercial development (which
had yet to be built at the time of trial).
   Consistent with the requirements of the Woodland
agreement, and after several rounds of negotiations
with Woodland, the defendants reluctantly agreed to
include list-back provisions in their purchase and sale
agreements for parcels 13 and 15. Specifically, BLT
agreed to enter into a listing agreement with Haddad
and Scalzo, pursuant to which the brokers would
receive a 3 percent commission on the subsequent sale
or lease of parcel 13, either as a whole or as individual
units. For its part, Windemere agreed to pay Haddad
and Scalzo $1 million for their efforts in leasing the
office space that Windemere planned to build on parcel
15. That fee was to be paid in ten annual increments
of $100,000, beginning when the first certificate of occu-
pancy was issued.3 After months of additional negotia-
tions, Woodland and the defendants finalized and
memorialized those list-back agreements in July, 2003.4
  Although Haddad and Scalzo made good faith efforts
to market parcels 13 and 15, the real estate market
softened in the wake of the 2007–2008 financial crisis,
and those efforts were unsuccessful. BLT ultimately
proceeded to build a luxury apartment complex on its
parcel, units of which it marketed through its own on-
site leasing agent instead of through the services of
Haddad and Scalzo.
   The plaintiffs responded by filing the present action,
alleging breach of contract and anticipatory breach, and
seeking, inter alia, specific performance of the listing
agreements. In response, the defendants raised a num-
ber of special defenses, three of which were at issue
in the plaintiffs’ appeal to the Appellate Court. Specifi-
cally, the defendants argued that the list-back provi-
sions in their purchase and sale agreements were not
enforceable by the plaintiffs because those provisions
(1) were illegal tying arrangements, (2) did not satisfy
the requirements of General Statutes § 20-325a,5 and (3)
were personal and specific to Haddad, who died prior
to the trial. Reserve Realty, LLC v. Windemere Reserve,
LLC, supra, 174 Conn. App. 138. Following a bench
trial, the trial court ruled for the defendants on all three
of these special defenses and rendered judgments
accordingly. The Appellate Court affirmed the judg-
ments on the basis of the antitrust defense and, there-
fore, declined to address the plaintiffs’ claims that the
trial court reached the incorrect conclusion on the
remaining special defenses.6 Id.
                             II
  The dispositive question in these appeals is whether
we should reconsider our tying jurisprudence and over-
rule Hossan-Maxwell, Inc. In part II A of this opinion,
we set forth certain well established background princi-
ples on which we understand the parties to be in agree-
ment. In part II B and C, we address the legal questions
that remain the subject of dispute between the parties.
                             A
   The defendants’ first special defense alleges that the
list-back provisions in the parties’ purchase and sale
agreements violate the Sherman Act, 15 U.S.C. § 1 et
seq., and are, therefore, unenforceable. See Kaiser Steel
Corp. v. Mullins, 455 U.S. 72, 76, 102 S. Ct. 851, 70 L.
Ed. 2d 833 (1982) (claim that agreement ‘‘was void and
unenforceable as violative of §§ 1 and 2 of the Sherman
Act’’); see also Hanks v. Powder Ridge Restaurant
Corp., 276 Conn. 314, 326, 885 A.2d 734 (2005) (‘‘con-
tracts that violate public policy are unenforceable’’
(internal quotation marks omitted)). The section of the
Sherman Act at issue provides in relevant part: ‘‘Every
contract, combination in the form of trust or otherwise,
or conspiracy, in restraint of trade or commerce among
the several [s]tates, or with foreign nations, is declared
to be illegal. . . .’’ 15 U.S.C. § 1 (2018). Although this
provision, on its face, prohibits any contract in restraint
of trade, the United States Supreme Court has added
a judicial gloss requiring a contractual restraint to be
unreasonable before it will be deemed illegal under the
Sherman Act.7 See, e.g., Board of Trade v. United States,
246 U.S. 231, 238–41, 38 S. Ct. 242, 62 L. Ed. 683 (1918);
Elida, Inc. v. Harmor Realty Corp., 177 Conn. 218,
225, 413 A.2d 1226 (1979); see also Bridgeport Harbour
Place I, LLC v. Ganim, 303 Conn. 205, 214, 32 A.3d 296
(2011) (‘‘an act is deemed anticompetitive under the
Sherman Act only when it harms both allocative effi-
ciency and raises the prices of goods above competitive
levels or diminishes their quality’’ (emphasis omitted;
internal quotation marks omitted)).
   The United States Supreme Court generally has
reviewed alleged Sherman Act violations under one of
two standards. ‘‘If a restraint alleged is among that small
class of actions that courts have deemed to have . . .
predictable and pernicious anticompetitive effect, and
. . . limited potential for procompetitive benefit, it will
be unreasonable per se . . . . Most antitrust claims,
however . . . are analyzed under a rule of reason anal-
ysis [that] seeks to determine if the alleged restraint is
unreasonable because its anticompetitive effects out-
weigh its procompetitive effects.’’ (Internal quotation
marks omitted.) Bridgeport Harbour Place I, LLC v.
Ganim, supra, 303 Conn. 214–15.
   Treating some practices as illegal per se allows courts
to recognize and efficiently resolve disputes concerning
practices that have little or no positive economic value
and are highly likely to be anticompetitive, without the
need for parties to engage in costly and complex litiga-
tion centering around competing expert testimony. See
9 P. Areeda & H. Hovenkamp, Antitrust Law (3d Ed.
2011) ¶ 1720a, pp. 260–61. On the other hand, presump-
tively applying a rule of reason to most alleged antitrust
violations (1) respects the freedom of competitors and
consumers to structure their economic relations as they
see fit, (2) recognizes that courts generally are ill-
equipped to identify those business practices that devi-
ate from the procompetitive norm and may be too quick
to choose economic winners and losers rather than
allowing the marketplace to sort things out, and (3)
requires proof that a challenged business practice actu-
ally imposes an unreasonable restraint on trade before
exposing a defendant to potential antitrust liability. See
7 P. Areeda & H. Hovenkamp, Antitrust Law (3d Ed.
2010) ¶ 1500, pp. 379–82; 9 P. Areeda & H. Hovenkamp,
supra, ¶ 1710c, pp. 110–13.
  In addition to the Sherman Act, the defendants allege
that the list-back provisions in their agreements also
violate the Connecticut Antitrust Act, General Statutes
§ 35-24 et seq. The primary allegation is that the list-
back provisions violate General Statutes § 35-26,8 the
state analogue of 15 U.S.C. § 1.9 It is well established
that the state antitrust act was patterned after federal
antitrust law. Bridgeport Harbour Place I, LLC v.
Ganim, supra, 303 Conn. 213 n.6. Indeed, General Stat-
utes § 35-44b provides that, in construing the antitrust
act, ‘‘the courts of this state shall be guided by interpre-
tations given by the federal courts to federal antitrust
statutes.’’ For this reason, ‘‘we follow federal precedent
when we interpret the [Connecticut Antitrust Act]
unless the text of our antitrust statutes, or other perti-
nent state law, requires us to interpret it differently
. . . .’’ (Internal quotation marks omitted.) Bridgeport
Harbour Place I, LLC v. Ganim, supra, 213 n.6; see
also Westport Taxi Service, Inc. v. Westport Transit
District, 235 Conn. 1, 15–16, 664 A.2d 719 (1995). Insofar
as neither party contends that § 35-26 should be inter-
preted differently from its federal counterpart, we limit
our analysis herein to the issue of whether the listing
agreements violate 15 U.S.C. § 1.
   The defendants allege that the agreements at issue
in the present case are illegal tying arrangements. ‘‘A
tying arrangement is an agreement by a party to sell
one product [the tying product] but only on the condi-
tion that the buyer also purchase a different (tied) prod-
uct, or at least agree that he will not purchase that
product from any other supplier.’’ State v. Hossan-Max-
well, Inc., supra, 181 Conn. 659. In its early antitrust
cases, the United States Supreme Court took a dim view
of tying arrangements because it assumed that (1) tying
confers little, if any, economic benefit or value, and
(2) tying allows a monopolist in the tying product to
improperly extend or leverage its monopoly position
so as to monopolize or obtain an unfair advantage in
the market for the complementary, tied product (the
dual monopoly profit theory). See Illinois Tool Works,
Inc. v. Independent Ink, Inc., 547 U.S. 28, 35, 126 S. Ct.
1281, 164 L. Ed. 2d 26 (2006). Because tying was viewed
as being almost invariably anticompetitive, the Supreme
Court initially classified tying among those trade prac-
tices deemed per se unlawful. See, e.g., Times-Pica-
yune Publishing Co. v. United States, 345 U.S. 594, 609,
73 S. Ct. 872, 97 L. Ed. 1277 (1953).
  The issue of the legality of broker list-back agree-
ments under federal and state antitrust law first arose
in the late 1970s and early 1980s. Consistent with the
United States Supreme Court’s then prevailing views
on tying arrangements, both this court and our sister
courts10 held such arrangements to be per se illegal
and, therefore, generally refused to enforce contracts
predicated on such an agreement.
   We addressed this issue in Hossan-Maxwell, Inc. A
brief review of the facts of that case is instructive.
In 1966, James F. Hartnett recorded a declaration of
covenants and restrictions on certain parcels of residen-
tial land in New Milford. State v. Hossan-Maxwell, Inc.,
supra, 181 Conn. 657. That declaration required that a
grantee of any of the sixty-four building lots who
decided to sell or lease the property through any com-
missioned broker give exclusive sales and leasing rights
to Hartnett for a period of three months. Id., 658. These
exclusive rights were intended to run with the land
and to bind not only the immediate grantee but all
subsequent purchasers. Id. Apparently, Hartnett
intended to charge a 6 percent commission for his ser-
vices, which was consistent with the prevailing market
rate. Id., 663, 665 n.7.
   In affirming the trial court’s judgment declaring the
restrictive covenants unenforceable, this court applied
not a true per se rule but, rather, the ‘‘quasi-per se’’ rule
that the United States Supreme Court articulated in
Northern Pacific Railway Co. v. United States, 356 U.S.
1, 78 S. Ct. 514, 2 L. Ed. 2d 545 (1958) (Northern Pacific).
See State v. Hossan-Maxwell, Inc., supra, 181 Conn.
660–67. Under the Northern Pacific rule, a tying
arrangement violates 15 U.S.C. § 1, without the need to
demonstrate any anticompetitive effects—that is, with-
out the need for a full rule of reason analysis—if the
following conditions are met: (1) the seller has suffi-
cient economic power with respect to the tying product
to appreciably restrain free competition in the market
for the tied product, and (2) a ‘‘not insubstantial amount
of interstate commerce is affected,’’ meaning that more
than a de minimis volume of business is foreclosed to
competitors by the tie. See id., 661–63.
   With respect to the first prong of the Northern Pacific
rule, economic power for antitrust purposes ordinarily
must be demonstrated by proving that a seller has a
substantial or dominant position (market power) in a
defined product and geographic market. See, e.g.,
Smugglers Notch Homeowners’ Assn., Inc. v. Smug-
glers’ Notch Management Co., Ltd., 414 Fed. Appx. 372,
375 (2d Cir. 2011); see also footnote 14 of this opinion.
Several United States Supreme Court cases decided
prior to Hossan-Maxwell, Inc., however, held that eco-
nomic power also can be established merely by demon-
strating that the tying product at issue is protected
as intellectual property or is a unique or especially
desirable item, the assumption being that that unique-
ness of the tying product can be leveraged to compel
an eager buyer to accept the tied product.11 See, e.g.,
International Salt Co. v. United States, 332 U.S. 392,
395–96, 68 S. Ct. 12, 92 L. Ed. 20 (1947); International
Business Machines Corp. v. United States, 298 U.S.
131, 135–37, 56 S. Ct. 701, 80 L. Ed. 1085 (1936); see
also Jefferson Parish Hospital District No. 2 v. Hyde,
466 U.S. 2, 17, 104 S. Ct. 1551, 80 L. Ed. 2d 2 (1984)
(‘‘when the seller offers a unique product that competi-
tors are not able to offer . . . [this] [c]ourt has held
that the likelihood that market power exists and is being
used to restrain competition in a separate market is
sufficient to make per se condemnation appropriate’’
(citation omitted)). In State v. Hossan-Maxwell, Inc.,
supra, 181 Conn. 665, this court read Northern Pacific
to mean that land—or at least residential land—also is
always unique. Accordingly, a landowner who ties the
sale of their land to the purchase of another product
or service necessarily has market power for purposes
of a court’s evaluation of an antitrust challenge. See id.
   This court also concluded in Hossan-Maxwell, Inc.,
that the second prong of the Northern Pacific rule was
satisfied because, under what the court described as
its ‘‘very liberal interpretation’’ of Northern Pacific, the
estimated $21,000 in annual real estate commissions
implicated by the declaration constituted a not insub-
stantial volume of business that was foreclosed to other
brokers. (Internal quotation marks omitted.) Id., 664.
   In the four decades since this court held in Hossan-
Maxwell, Inc., that any real estate list-back agreement
affecting more than a de minimis volume of commerce
is per se illegal, neither this court nor, to our knowledge,
any federal appellate court has had the opportunity to
consider the ongoing vitality of that rule. Although, in
addressing this question, we must defer to the trial
court’s factual findings, our interpretation of federal
and state antitrust laws is plenary. See, e.g., Miller’s
Pond Co., LLC v. New London, 273 Conn. 786, 798, 873
A.2d 965 (2005); Westport Taxi Service, Inc. v. Westport
Transit District, supra, 235 Conn. 14–15.
                             B
   We turn now to the primary issue presented by the
present appeals, namely, whether the reasoning and
result of this court’s decision in Hossan-Maxwell, Inc.,
remain consistent with the current views of the United
States Supreme Court and the lower federal courts with
respect to tying arrangements. The plaintiffs posit that
Hossan-Maxwell, Inc., has been vitiated by modern
antitrust case law or, at the very least, that we should
adopt a more nuanced approach to tying arrangements
such as that espoused by Justice O’Connor in her con-
curring opinion in Jefferson Parish Hospital District
No. 2 v. Hyde, supra, 466 U.S. 33–42. The defendants
respond that Hossan-Maxwell, Inc., remains fully con-
sistent with controlling United States Supreme Court
precedent and, therefore, should not be overruled.
Because we conclude that the trajectory of federal anti-
trust law, as informed by recent antitrust scholarship,
clearly is diverging from the traditional per se treatment
of tying arrangements, we agree with the plaintiffs that
the trial court should not have found the list-back agree-
ments at issue in this case unenforceable without first
engaging in a full market analysis.
                             1
   Before we review the evolution of the United States
Supreme Court’s tying jurisprudence, it will be instruc-
tive briefly to review some of the developments in anti-
trust scholarship that precipitated that evolution. Tying
was among the first areas in which modern antitrust
theory—often associated with the so-called ‘‘law and
economics’’ or ‘‘Chicago school’’ of thought—diverged
from courts’ traditional approach to competition prob-
lems. Beginning in the 1970s, antitrust scholars began
to challenge the two pillars that had supported courts’
per se treatment of tying arrangements, namely, the
dual monopoly profit theory and the axiom that tying
typically confers no economic benefit or value. Scholars
theorized—and purported to demonstrate—that, far
from being inherently anticompetitive, most tying
agreements are actually procompetitive.12 See, e.g., D.
Carlton & M. Waldman, ‘‘Robert Bork’s Contributions
to Antitrust Perspectives on Tying Behavior,’’ 57 J.L. &
Econ. S121, S121–22 (2014); R. Posner, ‘‘The Chicago
School of Antitrust Analysis,’’ 127 U. Pa. L. Rev. 925,
925–26 (1979). They also established that, in most
instances, control over a tying product does not allow
a monopolist to garner additional profits by cornering
the market for a tied product. See, e.g., Scheiber v.
Dolby Laboratories, Inc., 293 F.3d 1014, 1020 (7th Cir.
2002) (‘‘as [modern] cases and a tidal wave of legal and
economic scholarship point out, the idea that you can
use tying to lever your way to a second . . . monopoly
is economic nonsense’’), cert. denied, 537 U.S. 1109,
123 S. Ct. 853, 154 L. Ed. 2d 781 (2003).
    At a more fundamental level, recent scholarship has
highlighted the difficulty in distinguishing between a
packaged sale that is a tie—and, thus, presumptively
illegal under traditional antitrust jurisprudence—and a
product or service bundle, which is presumptively legal
and consumer friendly. As one author has explained,
‘‘[t]he most robust statement one can make about tying
is that it is ubiquitous. Consider the following examples:
shoes are sold in pairs; hotels sometimes offer break-
fast, lunch or dinner tied with the room; there is no
such a thing as an unbundled car; and no self-respecting
French restaurant would allow its patrons to drink a
bottle of wine not coming from its cellar.’’ C. Ahlborn
et al., ‘‘The Antitrust Economics of Tying: A Farewell
to Per Se Illegality,’’ 49 Antitrust Bull. 287, 287 (2004);
see also K. Hylton & M. Salinger, ‘‘Tying Law and Policy:
A Decision-Theoretic Approach,’’ 69 Antitrust L.J. 469,
526 (2001) (‘‘tying is so pervasive even in competitive
markets that there is ample evidence that procompeti-
tive tying is a common occurrence’’).
   Finally, antitrust scholars have cautioned against the
use of tying law to resolve ‘‘contract dispute[s] in which
one side got the benefit of the bargain and then sought
to have the contract declared a violation of the Sherman
Act.’’ K. Hylton & M. Salinger, ‘‘Reply to Grimes: Illusory
Distinctions and Schisms in Tying Law,’’ 70 Antitrust
L.J. 231, 239 (2002); see also Hemlock Semiconductor
Operations, LLC v. SolarWorld Industries Sachsen
GmbH, 867 F.3d 692, 701 (6th Cir. 2017) (‘‘illegality
defenses based on antitrust law are disfavored, espe-
cially when allowing the defense would let the buyer
escape from its side of a bargain after having received
a benefit’’ (internal quotation marks omitted)). See foot-
note 3 of this opinion.
                             2
    In the four decades since this court decided Hossan-
Maxwell, Inc., the foregoing scholarship has prompted
the United States Supreme Court to rethink its approach
to tying claims. In Jefferson Parish Hospital District
No. 2 v. Hyde, supra, 466 U.S. 32–33, Justice O’Connor
authored a concurring opinion, joined by three other
members of the court, in which she argued that the
tying arrangements at issue—patients obtaining surgery
at the defendant hospital were required to use a desig-
nated anesthesiology practice—should be evaluated
under the rule of reason. More generally, the concur-
rence, citing to recent antitrust scholarship, argued that
‘‘[t]he time has . . . come to abandon the ‘per se’ label
and refocus the inquiry on the adverse economic
effects, and the potential economic benefits, that the
tie may have.’’13 Id., 35 (O’Connor, J., concurring in the
judgment). Although a majority of the court continued
to apply the Northern Pacific quasi-per se rule to tying
claims in its next tying case; see Eastman Kodak Co.
v. Image Technical Services, Inc., 504 U.S. 451, 462,
112 S. Ct. 2072, 119 L. Ed. 2d 265 (1992); the dissent,
penned by Justice Scalia and joined by Justices O’Con-
nor and Thomas, again recognized the ‘‘intense criticism
of the [court’s] tying doctrine in academic circles
. . . .’’ Id., 487.
   Finally, in Illinois Tool Works, Inc., a majority of the
Supreme Court for the first time expressly repudiated
the court’s traditional disapproval of tying agreements.
Justice Stevens, writing for a unanimous court, under-
took ‘‘a fresh examination of the history of both the
judicial and legislative appraisals of tying arrangements
. . . informed by extensive scholarly comment and a
change in position by the administrative agencies
charged with enforcement of the antitrust laws.’’ (Cita-
tion omitted.) Illinois Tool Works Inc. v. Independent
Ink, Inc., supra, 547 U.S. 33. The court observed that,
‘‘[o]ver the years . . . [its] strong disapproval of tying
arrangements has substantially diminished. Rather than
relying on assumptions, in its more recent opinions the
[c]ourt has required a showing of market power in the
tying product.’’ Id., 35. Justice Stevens further explained
that, whereas the court traditionally had been of the
view that ‘‘[t]ying arrangements serve hardly any pur-
pose beyond the suppression of competition,’’ that view
had evolved with the recognition that ‘‘tying arrange-
ments may well be procompetitive . . . .’’ (Internal
quotation marks omitted.) Id., 35–36.
   Having thus framed the issue, the court in Illinois
Tool Works, Inc., proceeded to expressly overrule one
‘‘vestige of [its] historical distrust of tying arrangements
. . . .’’ Id., 38. As we discussed, in previous decisions,
the United States Supreme Court had indicated that the
first prong of the Northern Pacific rule—possession of
economic power in the tying product—can be estab-
lished not only by proving that a seller holds a dominant
position in a defined market for the tying product, but
also by demonstrating that the tying product is pre-
sumed to be uniquely desirable. In Northern Pacific
itself, the court suggested that the unique configuration
and choice location of the defendant’s land was suffi-
cient to confer economic power. Northern Pacific Rail-
way Co. v. United States, supra, 356 U.S. 7; see also
id., 16–20 (Harlan, J., dissenting). In prior decisions,
the court had likewise held that the monopoly conferred
by a patent presumptively confers market power for
purposes of a tying claim. See, e.g., International Salt
Co. v. United States, supra, 332 U.S. 395–96; Interna-
tional Business Machines Corp. v. United States, supra,
298 U.S. 136–37. Indeed, it was in the context of intellec-
tual property that the Supreme Court initially held that
tying arrangements are per se illegal. See Illinois Tool
Works, Inc. v. Independent Ink, Inc., supra, 547 U.S. 33.
   In Illinois Tool Works, Inc., the issue was whether
the court should depart from its long established rule
that a patent holder presumptively exerts market power
over the patented product for purposes of a tying allega-
tion. Id., 31. Overruling several of its prior tying deci-
sions; see id., 38–40; the court held that ‘‘the mere fact
that a tying product is patented does not support . . .
a presumption [of market power].’’ Id., 31. The court
emphasized that its new approach, which requires proof
that the seller holds market power in the relevant mar-
ket, is consistent with ‘‘the vast majority of academic
literature on the subject.’’ Id., 43–44 and n.4.
                            3
   The parties to the present case disagree as to the
scope of the Supreme Court’s decision in Illinois Tool
Works, Inc. The defendants contend that its holding
was limited to patented products, whereas the plaintiffs
contend that the court intended to depart more funda-
mentally from its prior view that the uniqueness of a
tying product can presumptively establish economic
power for purposes of Northern Pacific. The narrow
reading advocated by the defendants is consistent with
the fact that only the question of patents was before
the court in Illinois Tool Works, Inc., and that the court,
in overruling its prior patent tying cases, relied on vari-
ous factors that are specific to the patent context: recent
congressional amendments to the patent misuse stat-
utes, new guidance from the federal agencies charged
with the enforcement of the antitrust laws, and the
views of antitrust scholars regarding the overlap of
intellectual property and antitrust law. Id., 41–45.
  The plaintiffs’ broader reading of Illinois Tool Works,
Inc., however, finds support in the manner in which
the Supreme Court framed its holding, which appeared
to extend beyond the patent context. ‘‘Many tying
arrangements,’’ the court wrote, ‘‘even those involving
patents and requirements ties, are fully consistent with
a free, competitive market. . . . Congress, the antitrust
enforcement agencies, and most economists have all
reached the conclusion that a patent does not necessar-
ily confer market power upon the patentee. Today, we
reach the same conclusion, and therefore hold that, in
all cases involving a tying arrangement, the plaintiff
must prove that the defendant has market power in the
tying product.’’ (Citations omitted; emphasis added.)
Id., 45–46. The fact that the Supreme Court’s restrictive
tying jurisprudence originated in the patent context also
suggests that that court’s recent change of direction
with respect to the tying of patented products evinces
a broader rethinking of tying generally. Indeed, it would
be odd if the Supreme Court were to conclude that
holding a patent—a legal monopoly—over a product is
not sufficient to confer economic power but that mere
ownership of a parcel of land, without more, is suf-
ficient.
  Our impression that the plaintiffs have the better of
this argument is reinforced by the fact that most of the
lower federal courts and our sister state courts that
have considered the question have adopted the broader
reading of Illinois Tool Works, Inc., and interpreted the
decision to mean that the uniqueness of a tying product
no longer gives rise to a presumption of economic
power. Market power in a defined product and geo-
graphic market must be established to satisfy the first
prong of Northern Pacific, even with respect to unique,
nonpatented tying products such as land.14
   In Michigan Division-Monument Builders of North
America v. Michigan Cemetery Assn., 458 F. Supp. 2d
474, 476–77 (E.D. Mich. 2006), aff’d, 524 F.3d 726 (6th
Cir. 2008), the plaintiffs, a class of independent monu-
ment dealers, alleged that the defendant cemeteries
violated the Sherman Act by requiring that consumers
who wished to buy a burial plot also to purchase monu-
ments and related services from the cemetery. They
alleged that this tying scheme was per se illegal because
the uniqueness of burial land meant that each cemetery
constituted a distinct product and geographic market.
Id., 477. The federal District Court, granting the defen-
dants’ motion to dismiss the tying claims, concluded
that the alleged relevant geographic market—each indi-
vidual cemetery—failed as a matter of law. Id., 480–85.
The court reached that conclusion because, in its view,
‘‘the reasoning in [Illinois Tool Works, Inc.] makes it
clear that presumptions, whether based on the unique-
ness of a patent or the uniqueness of land, cannot sup-
port a valid antitrust claim.’’ Id., 484.
  The United States Court of Appeals for the Sixth
Circuit affirmed, opining that, under Illinois Tool
Works, Inc., ‘‘[t]he idea that all land is unique . . . is
insufficient to support a finding of market power.’’
Michigan Division-Monument Builders of North
America v. Michigan Cemetery Assn., supra, 524 F.3d
732. The Court of Appeals distinguished the holding
of Northern Pacific, concluding that, in that case, the
Supreme Court had affirmed a finding of economic
power not because commercial land in general is unique
but, rather, because there was other evidence showing
that the specific location of the land lent the seller a
competitive advantage that others could not achieve.
Id., 733. Specifically, the land at issue in Northern
Pacific was strategically located in checkerboard fash-
ion within economic distance of key transportation
facilities and, therefore, was essential to the business
activities of those who purchased or leased it. Id.,
732–33; see Northern Pacific Railway Co. v. United
States, supra, 356 U.S. 7.
  In so holding, the Sixth Circuit joined several other
appellate courts to have rejected—even prior to Illinois
Tool Works, Inc.—the theory that the uniqueness of
land, standing alone, is sufficient to create economic
power for purposes of the first prong of the Northern
Pacific rule. See, e.g., Smugglers Notch Homeowners’
Assn., Inc. v. Smugglers’ Notch Management Co., Ltd.,
supra, 414 Fed. Appx. 376 (rejecting ‘‘unique geographic
qualities of ski areas’’ as basis for finding of market
power (internal quotation marks omitted)); Baxley-
DeLamar Monuments, Inc. v. American Cemetery
Assn., 938 F.2d 846, 851 (8th Cir. 1991) (‘‘[A]ll land is
unique, but the mere fact that the tying product is real
estate does not convey market power. . . . In numer-
ous other tying cases involving real estate as the tying
product, courts have held that the real estate must have
some particular strategic or competitive importance in
order to carry market power.’’ (Citations omitted.));
McCormick v. Bradley, 870 P.2d 599, 604–605 (Colo.
App. 1993) (criticizing and declining to follow Hossan-
Maxwell, Inc.), cert. denied, Colorado Supreme Court,
Docket No. 93SC773 (April 11, 1994); Vande Guchte v.
Kort, 13 Neb. App. 875, 887, 703 N.W.2d 611 (2005) (‘‘we
do not accept the notion that the ‘uniqueness’ of land
by itself establishes economic power’’).
   More generally, other federal courts have read Illi-
nois Tool Works, Inc., to broadly hold that market
power in a defined product and geographic market
always must be established to proceed under the quasi-
per se rule in Northern Pacific. See, e.g., Auraria Stu-
dent Housing at the Regency, LLC v. Campus Village
Apartments, LLC, 843 F.3d 1225, 1246 (10th Cir. 2016);
Batson v. Live Nation Entertainment, Inc., 746 F.3d
827, 831–32 (7th Cir. 2014); Sheridan v. Marathon
Petroleum Co., LLC, 530 F.3d 590, 593–94 (7th Cir.
2008); Compliance Marketing, Inc. v. Drugtest, Inc.,
Docket No. 09-CV-01241-JLK, 2010 WL 1416823, *7 (D.
Colo. April 7, 2010); Mediacom Communications Corp.
v. Sinclair Broadcast Group, Inc., 460 F. Supp. 2d 1012,
1027 (S.D. Iowa 2006). It seems clear, then, that a per
se ban on list-back agreements, as applied in Hossan-
Maxwell, Inc., is inconsistent with federal antitrust law
as it has evolved over the past several decades.15
                            C
   We next consider three arguments offered by the
defendants that have not been fully addressed by the
preceding discussion. First, the defendants contend that
their antitrust special defense invokes not only the Sher-
man Act and its state analogues but also General Stat-
utes § 35-29, the Connecticut analogue of § 3 of the
Clayton Act, 15 U.S.C. § 14. The point matters, they
contend, because, in Hossan-Maxwell, Inc., this court,
following what appeared at that time to be the guidance
of the United States Supreme Court in Times-Picayune
Publishing Co. v. United States, supra, 345 U.S. 594,
concluded that tying claims brought under the Clayton
Act or its state analogue need to satisfy only one prong
of the rule set forth in Northern Pacific. See State v.
Hossan-Maxwell, Inc., supra, 181 Conn. 662. That is, a
tie could be deemed illegal per se merely on the basis
of the fact that it foreclosed a not insubstantial volume
of trade in the tied product, even if the seller lacked
economic power in the tying product market. If that
were the case, then the analysis in part II B of this
opinion, which addresses only the first prong of the
Northern Pacific rule, would likely be moot, insofar as
the plaintiffs do not dispute that a substantial volume
of trade is at issue.
   Although that reading of Times-Picayune Publishing
Co. was still considered plausible at the time that Hos-
san-Maxwell, Inc., was decided, since then, the federal
courts and antitrust scholars almost universally have
concluded that the standard for tying claims brought
under the Clayton Act is no different from the standard
for those brought under the Sherman Act. See, e.g.,
Sheridan v. Marathon Petroleum Co., LLC, supra, 530
F.3d 592 (‘‘[t]hough some old cases say otherwise, the
standards for adjudicating tying under the two statutes
are now recognized to be the same’’); De Jesus v. Sears,
Roebuck & Co., 87 F.3d 65, 70 (2d Cir.) (‘‘[W]e have
required allegations and proof of five specific elements
before finding a tie illegal . . . . These elements are
common to claims asserted under either the Sherman
or Clayton Acts.’’ (Citation omitted; internal quotation
marks omitted.)), cert. denied, 519 U.S. 1007, 117 S. Ct.
509, 136 L. Ed. 2d 399 (1996); In re Data General Corp.
Antitrust Litigation, 490 F. Supp. 1089, 1100 (N.D. Cal.
1980) (‘‘It was traditionally understood that a tying
arrangement would run afoul of [the] Clayton [Act] if
it satisfied . . . either . . . of the elements required
under the Sherman Act. . . . Recently, however, the
neat distinction between tying arrangements that vio-
late [the] Sherman [Act] and those that violate [the]
Clayton [Act] has faded beyond recognition.’’ (Citation
omitted.)); 2 P. Areeda & H. Hovenkamp, Antitrust Law,
(3d Ed. 2007) ¶ 301c, pp. 9–11 and n.28 (referring to
Times-Picayune Publishing Co. as ‘‘one obsolete
exception’’ to prevailing view); H. Hovenkamp, ‘‘Tying
Arrangements in the Real Estate Market: Federal Anti-
trust Law and Local Land Development Policy,’’ 33 Has-
tings L.J. 325, 334 (1981) (‘‘[s]ince Times-Picayune
[Publishing Co.] was decided, [the] distinction between
the [Sherman Act and the Clayton Act] has increasingly
been disregarded’’). Accordingly, we need not resolve
the parties’ dispute as to whether the defendants ade-
quately pleaded a violation of § 35-29, insofar as the
same legal standard applies to tying claims under both
federal acts and their state counterparts.
   Second, the defendants contend that other courts that
have considered the issue have agreed with Hossan-
Maxwell, Inc., that any list-back agreement that fore-
closes a not insubstantial volume of broker commis-
sions is per se illegal. That appears to have been the
consensus view in the late 1970s and early 1980s. See
footnote 10 of this opinion and accompanying text.
Although we have identified some contrary authority
even from that time period,16 the important point is that
all of the cases on which the defendants rely were
decided more or less contemporaneously with Hossan-
Maxwell, Inc., and well before the evolution in federal
tying law that we discussed in part II B of this opinion.
The fact that those cases were decided consistently with
Hossan-Maxwell, Inc., is, therefore, of little moment.
  Third, the defendants emphasize that, regardless of
whether federal antitrust law treats land as conferring
economic power for purposes of the Northern Pacific
rule, this court concluded in Hossan-Maxwell, Inc., that
land is inherently unique as a matter of Connecticut
common law. They contend, therefore, that the logic
of that decision remains sound regardless of whether
federal law has taken a different direction.
  It is true that, in Hossan-Maxwell, Inc., our conclu-
sion that the first prong of the Northern Pacific rule
was satisfied rested in part on the fact that, ‘‘[i]n Con-
necticut, the uniqueness and special characteristics of
a particular plot of land have long been recognized.
Anderson v. Yaworski, 120 Conn. 390, 395, 399, 181 A.
205 [1935].’’ State v. Hossan-Maxwell, Inc., supra, 181
Conn. 665. We agree with the plaintiffs, however, that
this court’s reliance on that principle, and on Anderson,
was misplaced.
   In Anderson, this court simply reiterated the well
established principle that contracts for the sale of real
estate usually may be specifically enforced because
each parcel of land has its own particular characteris-
tics such that a buyer may not consider an equivalently
priced parcel to be an adequate substitute. Anderson
v. Yaworski, supra, 120 Conn. 395. But the fact that a
parcel of land is deemed to be unique for purposes of
property and contract law has little, if anything, to do
with whether it is unique for purposes of antitrust law.
Antitrust law is concerned with whether a seller has
economic power—the ability to sell a product at a
supracompetitive price—which usually is possible only
when a seller controls a substantial share of a defined
market for a product for which there are no adequate
substitutes. See, e.g., Sheridan v. Marathon Petroleum
Co., LLC, supra, 530 F.3d 594; American Council of
Certified Podiatric Physicians & Surgeons v. Ameri-
can Board of Podiatric Surgery, Inc., 185 F.3d 606, 622
(6th Cir. 1999); Queen City Pizza, Inc. v. Domino’s
Pizza, Inc., 124 F.3d 430, 436–37 (3d Cir. 1997), cert.
denied sub nom. Baughans, Inc. v. Domino’s Pizza,
Inc., 523 U.S. 1059, 118 S. Ct. 1385, 140 L. Ed. 2d 645
(1998).
  In theory, a parcel of land could be sufficiently unique
to allow the owner to charge a supracompetitive price.
This appears to have been the case in Northern Pacific,
in which the land at issue afforded unique access to
essential transportation facilities.17 Northern Pacific
Railway Co. v. United States, supra, 356 U.S. 7. But
the fact that each house, for example, is unique in vari-
ous ways does not permit the owner to charge a supra-
competitive price when it comes time to sell. Indeed,
Anderson itself implicitly recognized this concept by
noting that the market value of a parcel of land may not
reflect its emotional value in the mind of the purchaser.
Anderson v. Yaworski, supra, 120 Conn. 395–96. At no
point does Anderson suggest that a property’s ‘‘peculiar
and special’’ emotional value; (internal quotation marks
omitted) id., 396; somehow translates into an above
market economic value.
  Indeed, many products and services are unique. Land,
used cars, purebred dogs, and private piano lessons are
examples. But the fact that these things are not wholly
fungible does not mean that every seller wields eco-
nomic power for antitrust purposes. In a sense, the
breeder has a tiny monopoly on Fido. There is no other
dog in the world quite like him, and his eventual owner
may come to think of him as priceless. Still, if the market
price for a purebred German shepherd puppy in Hart-
ford is $1200, and if other breeders have other German
shepherd puppies for sale at that price, then there is
no reason to expect that Fido’s breeder will be able to
exercise economic power and charge significantly more
for him simply because of his inherent uniqueness. By
extension, if Fido’s breeder began requiring that each
puppy buyer also purchase a leash from him, there
would be little concern that the sale of Fido might
unreasonably restrain competition in the leash market.
For similar reasons, we repudiate Hossan-Maxwell,
Inc., to the extent that it stands for the proposition
that the uniqueness of a parcel of land, standing alone,
confers market power for purposes of Northern Pacific.
                            D
   To reiterate, in light of what we perceive to be the
clear trajectory of federal tying law, as informed by
modern antitrust scholarship, we overrule Hossan-
Maxwell, Inc., to the extent that it held that real estate
list-back agreements affecting a not insubstantial vol-
ume of commerce are per se illegal. We hold instead
that challenges to list-back agreements, like most other
forms of tying agreements, are subject to the five ele-
ment test adopted by the United States Court of Appeals
for the Second Circuit in applying Northern Pacific and
its progeny: ‘‘To state a valid tying claim . . . a [party]
must allege facts plausibly showing that: [1] the sale of
one product (the tying product) is conditioned on the
purchase of a separate product (the tied product); [2]
the seller uses actual coercion to force buyers to pur-
chase the tied product; [3] the seller has sufficient eco-
nomic power in the tying product market to coerce
purchasers into buying the tied product; [4] the tie-in
has anticompetitive effects in the tied market; and [5]
a not insubstantial amount of . . . commerce is
involved in the tied market.’’ Kaufman v. Time Warner,
836 F.3d 137, 141 (2d Cir. 2016); accord Yentsch v.
Texaco, Inc., 630 F.2d 46, 56–57 (2d Cir. 1980). The
leading treatise on the subject recognizes this as the
prevailing test for tying claims. See 9 P. Areeda & H.
Hovenkamp, supra, ¶ 1702, pp. 33–34 and n.1. We fur-
ther emphasize that the third element of the test, eco-
nomic power, typically must be established by proving
that the defendant wields market power in a defined
product and geographic market. Kaufman v. Time War-
ner, supra, 143. ‘‘[T]he best way to plead market power
is to allege facts that, if proven, establish directly that
the price of the tied package is higher than the price
of components sold in competitive markets.’’ (Internal
quotation marks omitted.) Id.
                            III
   Finally, having clarified the standards that govern
antitrust challenges to real estate list-back agreements,
we consider whether the trial court’s judgments can be
affirmed, under the proper legal standard, on the basis
of the trial court’s express and implicit factual findings.
For the reasons that follow, we conclude that they
cannot.
                            A
   First, and most important, the defendants did not
plead the existence of any particular product or geo-
graphic market with respect to either the tying product
(land of some sort) or the tied product (real estate
broker services of some sort). Nor was any expert testi-
mony introduced that would allow the trial court (1)
to define those markets with any sort of precision for
purposes of assessing economic power, (2) to quantify
Woodland’s power over the relevant property market,
or (3) to assess the plaintiffs’ share or foreclosure of
the relevant broker service market.
   The trial court did not make any relevant findings
in this respect. It simply stated that, under Hossan-
Maxwell, Inc., the uniqueness of residential property
is sufficient evidence of economic power to satisfy the
first prong of Northern Pacific and, thus, that Wood-
land, as the sole owner of the Reserve parcels, had
sufficient economic power to restrain competition in
the market for the tied product, which it identified as
real estate listing broker’s services in the greater Dan-
bury area. The trial court did not explain how it reached
the conclusion that the relevant tied product market
was limited to the greater Danbury area rather than
some larger geographic area, or explain why the rele-
vant market was taken to be listing broker’s services
rather than a broader market, such as broker’s services
writ large, or a narrower one, such as the services
of listing brokers specializing in large commercial and
multifamily residential projects. The court also did not
make any findings to support its apparent determination
that the Reserve constituted the entire tying product
market, such as that the Reserve was uniquely desirable
and economically necessary because of its flexible zon-
ing or other distinct characteristics.18
   The Appellate Court, in affirming the trial court’s
judgments, implied that, in its view, the relevant tying
product market consisted of ‘‘large area[s] of undevel-
oped land . . . in the densely populated Northeast’’;
the court opined that the Reserve was a rare example
thereof. Reserve Realty, LLC v. Windemere Reserve,
LLC, supra, 174 Conn. App. 145. It is unclear on what
basis the Appellate Court reached these conclusions.
Although there was some evidence in the record sug-
gesting that there were few locations in Fairfield County
suitable for building a 450,000 to 1.5 million square foot
project, and also that flexible space with the sort of
zoning approvals that the Reserve had obtained was
very desirable, there is no indication that either (1) the
trial court credited that evidence, or (2) the evidence
bore out the Appellate Court’s apparent belief that large
tracts of undeveloped land represent the relevant prod-
uct market or that the northeastern United States (how-
ever that term might be defined) represents the relevant
geographic area. Specifically, there is no evidence in
the record by which the Appellate Court could have
applied the governing test and determined whether a
small but significant and nontransitory increase in price
with respect to the Reserve, or portions thereof, could
be sustained or would lead customers to look elsewhere
for substitute property. See footnote 14 of this opinion.
  For their part, the defendants have taken the seem-
ingly contradictory positions that either (1) the Reserve
constitutes its own unique, singular product and geo-
graphic market, or (2) the relevant property market is
national in scope. The fact that the defendants and
the courts below were able to articulate four different,
facially plausible but incommensurate geographic mar-
ket definitions—the Reserve itself, the greater Danbury
area, the Northeast, and the entire United States—high-
lights why expert economic testimony is necessary to
resolve the issue of whether Woodland held sufficient
power in a defined geographic market for land of some
particular sort that it could foreclose competition and
coerce buyers into accepting supracompetitive prices
in some particular product market.
                             B
   The second reason that the judgments cannot be sus-
tained is that, to establish the third and fourth elements
of a tying claim—economic power and anticompetitive
effect—a buyer typically must be able to establish that
the combined price for the tying product plus the tied
product exceeded the market price. Kaufman v. Time
Warner, supra, 836 F.3d 143; 9 P. Areeda & H. Hoven-
kamp, supra, ¶ 1702, p. 36. The trial court made no
findings to that effect, and we doubt that the current
record would support such findings. At trial, a represen-
tative of Woodland offered undisputed testimony that,
as a result of the need to resolve the plaintiffs’ adminis-
trative appeal, Woodland agreed to a purchase price
for parcels 13 and 15 that was significantly lower than
what the parties ordinarily would have negotiated at
arm’s length. He further testified that, following a series
of significant price reductions, the land sold for a mere
fraction of the appraised value. There is no reason to
believe, then, that the list-back agreements, on balance,
had an anticompetitive effect on pricing.
    We note in this regard that the fact that the defendants
may have felt ‘‘forced’’ to accept the plaintiffs’ broker
services in order to acquire portions of the Reserve,
while relevant to the second (coercion) prong of the
Second Circuit test, says little to nothing about whether
Woodland and the plaintiffs were able to exert market
power or suppress competition. There are at least two
reasons for this. First, the fact that a few individual
buyers were sufficiently interested in a purchase to be
willing to accept unwanted strings attached does not
imply that, as a general matter, the sellers held market
power. See, e.g., McCormick v. Bradley, supra, 870 P.2d
604–605; see also Grappone, Inc. v. Subaru of New
England, Inc., 858 F.2d 792, 796–97 (1st Cir. 1988)
(‘‘ ‘[M]arket power’ . . . means significant market
power—more than the mere ability to raise price only
slightly, or only on occasion, or only to a few of a seller’s
many customers. . . . Of course, virtually every seller
. . . has some customers who especially prefer its
product. But to permit that fact alone to show market
power is to condemn ties that are bound to be harmless,
including some that may serve some useful social pur-
pose.’’ (Citations omitted; emphasis omitted.)); 9 P.
Arreeda & H. Hovenkamp, Antitrust Law, supra, ¶
1718a, p. 244 (fact that tying arrangement interferes
with customer choice generally is irrelevant to anti-
trust analysis).
   Second, the record in the present case supports vari-
ous, possible explanations as to why the defendants
were reluctantly willing to accept Woodland’s condition
that they agree to use the plaintiffs’ broker services. It
may be, as the defendants contend, that obtaining flexi-
ble zoning permits for the Reserve gave Woodland mar-
ket power because the property became uniquely desir-
able and, in essence, a market of one. It also may be
the case, though, that Woodland offered the defendants
a very favorable, below market price for the land, either
because Woodland was desperate to terminate the
defendants’ zoning appeal that was blocking develop-
ment of the Reserve or because the brokerage require-
ment itself lowered the value of the property. If the
defendants were only ‘‘forced’’ to accept the brokerage
provision insofar as that was necessary for them to get
a sweetheart deal on the land, and they could have
secured comparable land elsewhere at a higher, market
price, then competition policy need not be overly con-
cerned that two sophisticated parties, engaged in a
unique negotiation, ultimately agreed to include the tie
as one of many negotiated provisions.19 At the very least,
expert testimony was necessary to shed light on the
fair market value of the property and the availability
of any comparable properties. See Grappone, Inc. v.
Subaru of New England, Inc., supra, 858 F.2d 798 (citing
United States Steel Corp. v. Fortner Enterprises, Inc.,
429 U.S. 610, 618 n.10, 620 n.13, 97 S. Ct. 861, 51 L. Ed.
2d 80 (1977), for proposition that, ‘‘to show market
power, [the] plaintiff must show that an appreciable
number of buyers accepted the tie in the absence of
other explanations for [their] willingness . . . to pur-
chase the package’’ (emphasis altered; internal quota-
tion marks omitted)).
                            C
   Third, competition policy generally is not offended
when only minor foreclosure of competition in the tied
market is possible. See 9 P. Areeda & H. Hovenkamp,
supra, ¶ 1704a pp. 54–55; id., Æ 1709a, pp. 88–89. In
the present case, even if the tied product market at
issue were to be defined narrowly, such as to include
only listing broker services for large commercial and
multifamily residential properties in Danbury, it seems
unlikely on this record either that the listing agreements
could have permitted the plaintiffs to monopolize that
market or that prevailing brokerage fees would rise as
a result.20
  The land at issue accounts for a very small share—
approximately 2 percent—of the total acreage of Dan-
bury, which the trial court assumed to be the relevant
geographic market.21 Common experience suggests that
the broker market features relatively low barriers to
entry (new brokers easily can enter the market) and
limited economies of scale (smaller brokerage compa-
nies and even individuals can effectively compete with
larger firms because there is limited overhead, etc.).
The listing agreements locked in a relatively low com-
mission rate that may even have been below the market
rate. Moreover, the agreements appear to apply only to
the initial sale of each portion of the property, which
represents a new addition to the town’s building stock,
so there is no long-term foreclosure (unlike in Hossan-
Maxwell, Inc.) and no foreclosure of the existing build-
ing stock. Finally, the defendants testified that it was
their ordinary practice to use their own in-house sales
personnel, rather than other independent brokers, to
market developments of this sort, and, in any event,
prospective buyers were not precluded from using their
own buyers’ brokers, who could obtain a share of the
commissions. In short, it seems highly unlikely that
these agreements could permit the plaintiffs to corner
the market for commercial broker services in Danbury,
to the extent that that is the relevant market, or increase
the average cost of broker commissions in that market.
For all of these reasons, we conclude that, in light of our
clarification of the legal standard governing antitrust
challenges to tying arrangements, the trial court incor-
rectly determined that the defendants prevailed on their
antitrust special defense.
  The judgments of the Appellate Court are reversed
and the cases are remanded to that court with direction
to consider the plaintiffs’ remaining claims.
   In this opinion the other justices concurred.
   * March 24, 2020, the date that this decision was released as a slip opinion,
is the operative date for all substantive and procedural purposes.
   1
     Such agreements may apply only to the initial sale/lease of the property,
to all subsequent sales/leases that occur within a specified time frame, or
in perpetuity.
   2
     Haddad operated under the business name ‘‘Jeanette Haddad, Broker,’’
and Scalzo operated through his real estate franchise, Century 21 Scalzo
Realty, Inc. (Scalzo Realty). For simplicity, we do not distinguish between
those individuals and their corporate entities in this opinion, referring to
them, respectively, as ‘‘Haddad’’ and ‘‘Scalzo.’’ We note that, subsequent to
the filing of their action, Scalzo Realty was added as a necessary party but
thereafter was defaulted for failure to plead. Subsequently, the plaintiffs
withdrew their action as to Scalzo Realty.
   3
     It is not entirely clear that the agreements governing parcel 15 are true
list-back agreements. Although they include a reference to exclusive listing
of that property, those agreements could plausibly be read to mean that the
plaintiffs earned the $1 million commission on the completion of the sale
of that parcel by Woodland to Windemere, on the basis of the plaintiffs’
role in facilitating that sale, and that payment was simply to be delayed
until Windemere was able to develop the property. The trial court, for
example, having found the parties’ various purchase and listing agreements
to be ambiguous, concluded that one possible interpretation of the agree-
ments was that the plaintiffs had earned a commission with respect to parcel
15 prior to having performed any services for Windemere. Should these
cases ultimately return to the trial court, it will fall to that court to determine
whether those agreements are list-back agreements, the enforcement of
which potentially implicates antitrust considerations or, rather, merely con-
sideration for the plaintiffs’ prior services. Compare, e.g., Kaiser Steel Corp.
v. Mullins, 455 U.S. 72, 81–82, 102 S. Ct. 851, 70 L. Ed. 2d 833 (1982) (illegality
defense should be entertained in those circumstances in which its rejection
would be to enforce conduct forbidden by antitrust law), with Kelly v.
Kosuga, 358 U.S. 516, 521, 79 S. Ct. 429, 3 L. Ed. 2d 475 (1959) (rejecting
illegality defense when judgment would not have enforced allegedly illegal
aspect of contract).
   4
     The precise terms of the various contract documents vary, and are
ambiguous, in ways that are not directly relevant to the legal issues now
before us but that likely will need to be addressed on remand.
   5
     Among other things, § 20-325a places certain restrictions on the ability
of a real estate broker to bring an action to recover commissions arising
out of a real estate transaction.
   6
     In order for the plaintiffs to prevail, all three of these defenses must fail
on appeal.
   7
     More broadly, this provision of the Sherman Act, which is only a few
sentences long, is understood effectively to delegate to the courts the author-
ity to determine what constitutes an unreasonable restraint of trade and,
therefore, an antitrust violation. See In re Cox Enterprises, Inc., 871 F.3d
1093, 1097 (10th Cir. 2017). As a result, although antitrust actions and
defenses technically are statutory, judicial decisions interpreting and
applying the Sherman Act tend to analyze antitrust issues more like common-
law questions, with public policy and economic concerns at the forefront,
rather than according to traditional methods of statutory construction. See
R. Posner, ‘‘The Meaning of Judicial Self-Restraint,’’ 59 Ind. L.J. 1, 5–6 (1983);
see also 2 P. Areeda & H. Hovenkamp, Antitrust Law (3d Ed. 2007) ¶ 301a,
pp. 6–7.
   We further note that, to the extent that the trial court read General Statutes
§ 35-26 literally to prohibit any ‘‘contract, combination, or conspiracy in
restraint of any part of trade or commerce’’; see footnote 8 of this opinion;
that court’s reading was incorrect. Every commercial contract, by definition,
constitutes a restraint of trade. Procaps S.A. v. Patheon, Inc., 845 F.3d 1072,
1081 (11th Cir. 2016). If a dog breeder contracts to sell three puppies to a
family, commerce in those three puppies is restrained, insofar as no other
customer may purchase them. The antitrust laws proscribe only those con-
tracts that unreasonably restrain trade. See, e.g., id.; Tremont Public Advi-
sors, LLC v. Connecticut Resources Recovery Authority, 333 Conn. 672,
695, 217 A.3d 953 (2019).
   8
     General Statutes § 35-26 provides: ‘‘Every contract, combination, or con-
spiracy in restraint of any part of trade or commerce is unlawful.’’
   9
     The parties disagree as to whether the defendants’ antitrust special
defense also can be understood to allege a violation of General Statutes
§ 35-29, the state analogue of § 3 of the Clayton Act, 15 U.S.C. § 14. Because
we conclude that tying arrangements are evaluated under the same legal
standard under both the Sherman Act and the Clayton Act, we need not
resolve this dispute. See part III C of this opinion. Moreover, although the
defendants correctly note that § 35-29 is broader in scope than § 3 of the
Clayton Act—insofar as the former statute, unlike the latter, (1) applies to
anticompetitive conduct in the provision of services as well as commodities,
and (2) is not limited to interstate commerce—the defendants do not contend
that anything in the text or history of § 35-29 warrants the application of a
different legal standard.
   10
      See, e.g., Miller v. Granados, 529 F.2d 393, 396–97 (5th Cir. 1976);
MacManus v. A. E. Realty Partners, 146 Cal. App. 3d 275, 288, 194 Cal.
Rptr. 567 (1983); King City Realty, Inc. v. Sunpace Corp., 291 Or. 573, 581,
633 P.2d 784 (1981); see also In re Real Estate Litigation, 95 Wn. 2d 297,
301–304, 622 P.2d 1185 (1980) (addressing jurisdictional issues).
   11
      Although courts sometimes use the terms ‘‘economic power’’ and ‘‘mar-
ket power’’ interchangeably, in this opinion, for clarity, we use the term
‘‘economic power’’ in the more general sense to encompass all of the various
factors that courts have indicated may satisfy the first prong of Northern
Pacific. These include not only market power (a substantial or dominant
share of a defined, distinct market), but also uniqueness, special desirability,
a legal monopoly such as a patent, and anything else that might permit a
seller to force a buyer to agree to acquire an unwanted tied product.
   12
      A tying arrangement, such as requiring that consumers purchase laces
in tandem with a new pair of shoes or commit to buying a vendor’s paper
when purchasing its photocopy machines, might, for example, result in
increased efficiencies, satisfy consumer preferences for bundled sales, pro-
tect a seller’s good will, or facilitate economically desirable forms of price
discrimination. See, e.g., 9 P. Areeda & H. Hovenkamp, supra, ¶ 1703g, pp.
51–54; 9 P. Areeda & H. Hovenkamp, supra, ¶ 1720, pp. 259–61; D. Carlton &
M. Waldman, ‘‘Robert Bork’s Contributions to Antitrust Perspectives on
Tying Behavior,’’ 57 J.L. & Econ. S121–26 (2014).
   13
      Justice O’Connor’s concurring opinion went so far as to argue that tying
arrangements should be deemed presumptively legal, unless (1) the seller
has market power in the tying product market, (2) there is ‘‘a substantial
threat that the tying seller will acquire market power in the [tied product]
market,’’ and (3) the tied product is one that some consumers might wish
to purchase separately without also purchasing the tying product. Jefferson
Parish Hospital District No. 2 v. Hyde, supra, 466 U.S. 37–39. If all three
conditions are met, then the antitrust claims would be evaluated under a
rule of reason analysis. Id.
   14
      We note that defining a relevant product and geographic market for
purposes of the federal antitrust laws is a highly technical process that
typically requires expert testimony. See, e.g., McWane, Inc. v. Federal Trade
Commission, 783 F.3d 814, 829 (11th Cir. 2015), cert. denied,           U.S.    ,
136 S. Ct. 1452, 194 L. Ed. 2d 550 (2016); Hynix Semiconductor, Inc. v.
Rambus, Inc., Docket No. CV-00-20905 RMW, 2008 WL 73689, *10 n.13 (N.D.
Cal. January 5, 2008). The most common test of a proposed market definition
asks whether there is sufficient cross-elasticity of demand that a small but
significant and nontransitory price increase will lead customers to look
elsewhere—both productwise and geographically—for substitutes. See, e.g.,
DSM Desotech, Inc. v. 3D Systems Corp., 749 F.3d 1332, 1339–40 (2014);
Theme Promotions, Inc. v. News America Marketing FSI, 546 F.3d 991,
1002 (2008). Only once the relevant product and geographic markets have
been carefully defined can the trier of fact assess the relevant antitrust
variables, whether it be market share, economic power, market concentra-
tion, barriers to entry, or the like.
   15
      Indeed, given the recent evolution of the tying doctrine in the federal
courts, it is fair to ask whether the Northern Pacific rule, in its present
form, should continue to be considered a per se prohibition on tying in any
sense. See, e.g., 9 P. Areeda & H. Hovenkamp, Antitrust Law, supra, ¶ 1728c,
pp. 375–76 (explaining that most lower courts now allow defendants to raise
defense that tying arrangement is affirmatively justified by fact that it confers
benefits not available by alternative means); E. Elhauge, ‘‘Tying, Bundled
Discounts, and the Death of the Single Monopoly Profit Theory,’’ 123 Harv.
L. Rev. 397, 425–26 (2009) (‘‘It . . . now seems likely that a tie can be
justified by evidence that the tie is the least restrictive way to achieve
efficiencies large enough to offset the anticompetitive effects. Accordingly,
today it is more accurate to read Supreme Court precedent on tying as
embracing a rule of reason, where anticompetitive effects must be shown
or inferred and procompetitive justifications are admissible.’’); see also
United States v. Microsoft Corp., 253 F.3d 34, 84 (D.C. Cir.) (rule of reason,
rather than per se analysis, governs legality of tying arrangements involving
platform software products), cert. denied, 534 U.S. 952, 122 S. Ct. 350, 151
L. Ed. 2d 264 (2001).
   16
      See, e.g., Fran Welch Real Estate Sales, Inc. v. Seabrook Island Co., 621
F. Supp. 128, 137–38 (D.S.C. 1985) (summary judgment on real estate list-
back claim deemed inappropriate when (1) relevant market had not been
defined, and (2) six month exclusive listing agreement was likely too short
to unreasonably restrain competition), aff’d, 809 F.2d 1030 (4th Cir. 1987);
Outdoor Resorts of America, Inc. v. Outdoor Resorts at Nettles Island, Inc.,
379 So. 2d 471, 471–72 (Fla. App.) (rule of reason governed claim that
purchase of recreational vehicle lot was tied to developer’s exclusive right
to rent lots at 50 percent commission when not in use), cert. denied, 388
So. 2d 1116 (Fla. 1980); see also Vande Guchte v. Kort, supra, 13 Neb. App.
887 (holding that builder tie-in contract, which conditioned sale of lot on
use of specific builder, was not per se illegal).
   17
      In some sense, then, Northern Pacific can be understood as an applica-
tion of the essential facilities doctrine, which applies in antitrust cases in
which a monopolist controls access to uniquely necessary infrastructure,
such as a railroad or a port. See, e.g., MCI Communications Corp. v. Ameri-
can Telephone & Telegraph Co., 708 F.2d 1081, 1132 (7th Cir.), cert. denied,
464 U.S. 891, 104 S. Ct. 234, 78 L. Ed. 2d 226 (1983).
   18
      For these same reasons, the trial court’s conclusions that the listing
agreements violated General Statutes § 35-27, which prohibits attempted
monopolization, and General Statutes § 35-28, which prohibits price fixing
arrangements, also cannot be sustained. At the same time, the fact that the
necessary market analyses were not performed means that we need not
address the plaintiffs’ other claims, such as that the Appellate Court incor-
rectly concluded that the defendants were coerced into agreeing to the
list-back provisions and that the Reserve market was foreclosed to other
commercial brokers.
   We note that there was testimony at trial that three such ‘‘floating zone’’
properties were available in Danbury alone, which would seem to militate
against the plaintiffs’ theory that the Reserve was uniquely desirable. The
trial court neither credited nor declined to credit that testimony.
   19
      Although the trial court rejected the latter theory in its memorandum
of decision, it did so not as the result of any contrary factual findings but,
rather, because the court was of the view that, because any leverage that
the defendants were able to assert by virtue of their administrative appeal
was legal, it was irrelevant to the antitrust analysis. As we have explained,
the court was mistaken in that regard.
   Notably, the defendants conceded at trial that they proceeded to purchase
the land, despite the list-back requirements, because it made good economic
sense to do so and they believed that the deal was likely to be profitable.
For their part, representatives of Woodland testified that they had procom-
petitive reasons for agreeing to adopt the list-back provisions in the first
place, notably, the enhanced efficiency and quality control stemming from
having a single team of brokers coordinate marketing for the Reserve, as
well as the ability to negotiate below market commission rates.
   20
      Of course, should a retrial ultimately be necessary, the parties will have
the opportunity to make a record, and the trial court to make findings, about
all of these factual issues. In this part of the opinion, we merely explain
why, on the present record, we cannot impute to the trial court the findings
necessary to sustain the judgment.
   21
      The Reserve, taken as a whole, spans 546 acres. We may take judicial
notice of the fact that this represents two percent of the 42 square mile
area of the city of Danbury. See Connecticut Economic Resource Center,
Danbury, Connecticut: CERC Town Profile 2019, (January 16, 2020), p.
1, available at http://s3-us-west-2.amazonaws.com/cerc-pdfs/2019/danbury-
2019.pdf (last visited March 23, 2020).
