Academy of Allergy & Asthma in Primary Care v. AMERIGROUP TENNESSEE, INC., dba Amerigroup Community Care

RECOMMENDED FOR PUBLICATION
Pursuant to Sixth Circuit I.O.P. 32.1(b)
File Name: 26a0009p.06
UNITED STATES COURT OF APPEALS
FOR THE SIXTH CIRCUIT
ACADEMY OF ALLERGY & ASTHMA IN PRIMARY CARE,
Plaintiff,
UNITED BIOLOGICS, LLC, dba United Allergy
Services,
Plaintiff-Appellant,
v.
AMERIGROUP TENNESSEE, INC., dba Amerigroup
Community Care; PHYSICIANS’ MEDICAL
ENTERPRISES, LLC, dba PME Communications, LLC;
ALLERGY ASSOCIATES, P.A., dba Allergy, Asthma and
Sinus Center, P.C.; NED DELOZIER,
Defendants-Appellees.
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No. 24-5153
On Petition for Rehearing En Banc
United States District Court for the Eastern District of Tennessee at Knoxville.
No. 3:19-cv-00180—Travis Randall McDonough, District Judge.
Decided and Filed: January 13, 2026
Before: SUTTON, Chief Judge; KETHLEDGE and MURPHY, Circuit Judges.
_________________
COUNSEL
ON PETITION FOR REHEARING EN BANC and REPLY: Casey Low, Dillon J. Ferguson,
Michael H. Borofsky, Sarah Goetz, PILLSBURY WINTHROP SHAW PITTMAN LLP, Austin,
Texas, for Appellant. ON RESPONSE: Martin J. Bishop, Kevin Tessier, CROWELL &
MORING LLP, Chicago, Illinois, for Appellees.
The court delivered an ORDER denying the petition for rehearing en banc. BUSH, J. (pp.
3–18), delivered a statement respecting the denial of the petition for rehearing en banc. MURPHY,
J. (pp. 19–24), also delivered a separate opinion, in which SUTTON, C.J. and KETHLEDGE, J.,
joined, concurring in the denial of the petition for rehearing en banc.
>

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_________________
ORDER
_________________
The court received a petition for rehearing en banc. The original panel has reviewed the
petition for rehearing and concludes that the issues raised in the petition were fully considered
upon the original submission and decision.
The petition was then circulated to the full court. No judge requested a vote on the
suggestion for rehearing en banc.
Therefore, the petition is denied.

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__________________
STATEMENT
__________________
JOHN K. BUSH, Circuit Judge, respecting the denial of rehearing en banc. This case
involves an alleged conspiracy to restrain trade in the market for allergy testing and
immunotherapy in Tennessee. The First Amended Complaint (FAC) states that defendant-
appellee Allergy Associates has a 70% market share and that plaintiff-appellant United Allergy
challenged this dominance when it teamed up with primary care physicians (PCPs) to create new
competition. According to United Allergy, it provided staffing and supplies so that PCPs could
provide similar services to those offered by Allergy Associates. But the venture between United
Allergy and the PCPs failed. The reason, according to the FAC, was that Allergy Associates made
unfounded accusations to several insurance companies (who are also named defendants) that the
PCPs’ practices were fraudulent and encouraged those insurers to deny reimbursement to PCPs
for services provided jointly by United Allergy and the PCPs. The FAC alleges what amounts to
a group boycott by the insurers that Allergy Associates orchestrated. R. 103, FAC, PageID 2715.
United Allergy came to federal court for relief, but the panel in this appeal found no
antitrust standing. It characterized United Allergy as only a supplier to the PCPs. United Allergy
therefore lacked a direct contractual relationship with Allergy Associates or the insurance
companies, which the panel believes is required. The panel relied on Illinois Brick Co. v. Illinois,
which held that indirect purchasers (i.e., customers of the defendant’s victim who was
overcharged) cannot sue for damages under the Sherman and Clayton Acts based on the victim
passing on the overcharge to those customers. 431 U.S. 720, 735–36 (1977).
I respect the panel’s decision as reasonably applying Supreme Court precedent. But I write
separately to suggest that this case may warrant the Court’s review to clarify the parameters of
Illinois Brick in the context of an alleged group boycott and plaintiffs that operated essentially as
part of an apparent joint venture.
As discussed below, there is another competing view of the precedent which aligns with
the pragmatic view of antitrust law that the Supreme Court generally takes. See generally Am.

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Needle, Inc. v. Nat’l Football League, 560 U.S. 183, 191 (2010) (“[W]e have eschewed such
formalistic distinctions in favor of a functional consideration of how the parties involved in the
alleged anticompetitive conduct actually operate.”). Under this approach, United Allergy has
alleged enough to show antitrust standing.
The panel’s holding to the contrary may make it very difficult, if not impossible, for
participants in a joint venture—how I characterize the arrangement between United Allergy and
each PCP1—to bring Sherman Act claims. A basic premise of federal antitrust law is that even
the smallest companies should have the opportunity to enter a market without illegal interference
by incumbents. And sometimes a joint venture is the most efficient means—indeed, it may be the
only way—through which new competitors can challenge an entrenched entity.
I fear the panel’s decision will undermine important legal protections for such new market
entrants. As a result, consumers will be harmed. As Judge Kethledge emphasized in his
concurrence to the panel opinion, the majority’s decision may be an eminently defensible
application of governing precedent. But as he also noted, if the pleaded allegations are true,
patients will pay more and suffer from less-available allergy and immunotherapy treatments,
particularly in rural areas. More broadly, I worry that consumers in general may suffer because
the panel may have created a virtually insurmountable hurdle for certain joint-venture participants
to sue when a group boycott drives them out of a market.
I.
My concerns with the panel opinion are four-fold. First, I do not think a challenge to an
alleged group boycott brought by a joint-venture participant (the fact pattern here) raises the
calculation-of-damages problem posed by a challenge of an indirect purchaser to an overcharge
(the fact pattern of Illinois Brick). Second, the panel’s approach, while faithful to precedent, may
be more formalistic than the Supreme Court would follow if it reviewed this case. Third, the panel
opinion reads the Court’s precedents that apply Illinois Brick differently than I would. Fourth, the
1In the parties’ home State of Tennessee, a joint venture is “a single business adventure for joint profit, for
which purpose they combine their efforts, property, money, skill, and knowledge” but do not “creat[e] a partnership
in the legal or technical sense of the term.” Fain v. O’Connell, 909 S.W.2d 790, 793 (Tenn. 1995) (cleaned up).

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panel held that Illinois Brick bars a suit for injunctive relief, even though the Court has never
endorsed such a holding and other circuits have expressly rejected it.
A.
My first concern is that the panel applied the Illinois Brick rule to a group-boycott case that
does not involve overcharge damages.
In Illinois Brick, the Supreme Court sought to mitigate the potential problems with
overcharge plaintiffs who bring antitrust actions. As the Court explained, allowing an indirect
purchaser to sue over supra-competitive prices paid by the direct purchaser and then passed down
the chain would require “trac[ing] the effects of the overcharge on the purchaser’s prices, sales,
costs, and profits, and of showing that these variables would have behaved differently without the
overcharge.” Illinois Brick, 431 U.S. at 725. In other words, a court would need to figure out
(1) what the competitive price would have been, (2) what the direct purchaser would have charged
the indirect purchaser if the direct purchaser paid the competitive price, (3) what the indirect
purchaser would have charged its customers if the direct purchaser paid the competitive price, and
(4) what the indirect purchaser’s profits ultimately would have been without the defendant’s
anticompetitive conduct.
Calculating the direct purchaser’s loss is easy because we can determine the competitive
price and then subtract that from the supra-competitive price it actually paid. See Phillip E. Areeda
& Herbert Hovenkamp, Antitrust Law: An Analysis of Antitrust Principles and their Application
¶ 395 (2022). But damages get more speculative the further down the chain we go. Because it is
unclear whether the direct purchaser (or the indirect purchaser) would have charged a different
price had the defendant not charged supra-competitive prices, we do not know whether the indirect
purchaser would ultimately have suffered any harm.2 And we are not supposed to speculate about
2In his concurrence in the denial of rehearing en banc, Judge Murphy neglects this rationale for Illinois Brick
(that is, to avoid speculative damages) when he suggests that overcharge damages and group boycott damages should
be treated the same for antitrust standing purposes. See Murphy Concurrence at 19–20. The Court’s reasoning in
Illinois Brick stemmed from its “unwillingness to complicate treble-damages actions with attempts to” calculate the
overcharge damages. Illinois Brick v. Illinois, 431 U.S. 431 U.S. 720, 725 (1977). And “a speculative or illogical
theory of damages” is a “traditional proximate-cause problem . . . .” Trollinger v. Tyson Foods, Inc., 370 F.3d 602,
615 (6th Cir. 2004). So proximate causation—the requirement arising from the “by reason of” text emphasized by

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whether a plaintiff has suffered damages. See Story Parchment Co. v. Paterson Parchment Paper
Co., 282 U.S. 555, 562–63 (1931).
Those concerns do not exist in a group boycott as alleged here. Calculating damages from
such a group boycott is relatively easy: they are the profits the victim would have made if it were
not driven from the market. See Olsen v. Progressive Music Supply, Inc., 703 F.2d 432, 439 (10th
Cir. 1983). And, for a group boycott that harms a joint venture as alleged here, damages to each
venture participant may be calculated based on the agreed-upon share of revenue that each
participant would have received from sales lost because of the boycott. See generally Areeda &
Hovenkamp ¶ 397a (explaining that the measure of damages is the plaintiff’s net profits—i.e., the
revenue one participant would have made minus the fees paid to the other participant).
This logic finds support from out-of-circuit precedent indicating that Illinois Brick
generally does not apply in group-boycott cases. Writing for a unanimous Seventh Circuit, then-
Chief Judge Posner observed that “the Illinois Brick rule, which is a rule concerning overcharges,
would fall away” if the plaintiff asserted the defendants were boycotting it. In re Brand Name
Prescription Drugs Antitrust Litig., 123 F.3d 599, 606 (7th Cir. 1997), abrogated in part on other
grounds by Rivet v. Regions Bank of La., 522 U.S. 470 (1998). The Second Circuit later adopted
that statement as a holding, explaining that Illinois Brick does not bar a suit when the “[p]laintiffs
seek damages not for losses incurred due to increasing prices, but instead, for losses incurred as a
result of lost access” to the market. Mosaic Health, Inc. v. Sanofi-Aventis U.S., LLC, 156 F.4th
68, 80 (2d Cir. 2025) (cleaned up). The Second and Seventh Circuits therefore interpret the “by
reason of” language as “prohibit[ing] indirect sellers from suing if they allege a downstream
horizontal cartel” caused them to pay an overcharge and “permit[ting] indirect sellers to sue if they
Judge Murphy—should turn on whether damages are speculative or not. That, I submit, is the true underpinning of
the Illinois Brick “bright-line rule . . . .” Apple v. Pepper, 587 U.S. 273, 280 (2019). And that bright-line rule need
not be so broad as to deny a plaintiff antitrust standing where, as here, damages are relatively easy to calculate.
Indeed, the Court in Hanover Shoe, Inc. v. United Shoe Machinery Corp.—the case that ultimately led to the
Illinois Brick rule—determined that “an overcharged buyer” with “a pre-existing ‘cost-plus’ contract” would fall
outside the indirect purchaser rule’s scope because it would be “easy to prove” the indirect purchaser’s damages. 392
U.S. 481, 494 (1968). Likewise, here, United Allergy’s damages from the group boycott would seem to be relatively
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allege a downstream group boycott” caused them to lose profits as a result of lost access to the
market. Murphy Concurrence at 20 (emphasis deleted).
B.
My second concern is with the panel’s formalistic view of antitrust standing. The Supreme
Court directs that we analyze a business practice’s “demonstrable economic effect rather
than . . . [engage in] formalistic line drawing.” Leegin Creative Leather Prods., Inc. v. PSKS, Inc.,
551 U.S. 877, 887 (2007) (quoting Cont’l T. V., Inc. v. GTE Sylvania, 433 U.S. 36, 58–59 (1977))
(cleaned up). But, I fear, the panel does the latter when it observes that United Allergy “resembles
a ‘supplier’ to the primary-care physicians and operates in a distinct market vertically upstream of
the affected one.” Acad. of Allergy & Asthma in Primary Care v. Amerigroup Tennessee, Inc.,
155 F.4th 795, 810 (6th Cir. 2025) (quoting Static Control Components, Inc. v. Lexmark Int’l, Inc.,
697 F.3d 387, 404, 406 (6th Cir. 2012), aff’d, 572 U.S. 118 (2014)). That might be true in the
literal sense that United Allergy provides equipment and specialist technicians to the PCPs. But
the FAC also alleges that United Allergy and the PCPs combine inputs to provide products and
services in a particular market, R. 103, FAC, PageID 2671, which looks more like a joint venture
than the typical arrangement between supplier and manufacturer.
The panel was right to note that United Allergy cannot provide allergy testing or
immunotherapy by itself because it needs doctors for that. Amerigroup, 155 F.4th at 810. But by
the same token, the PCPs cannot provide the allergy testing and immunotherapy by themselves,
either, because they do not have the staff, equipment, and products to provide that service. In other
words, the business model does not work without both United Allergy’s and the PCPs’
participation. Unlike a traditional supplier-manufacturer relationship, United Allergy and the
PCPs function as one because they are jointly providing a service to that market. See R. 103, FAC,
PageID 2671 (“Since 2009, UAS technicians and more than 2,000 primary care physicians have
jointly provided allergy testing and allergen immunotherapy across 29 states.”).
The joint nature of the business venture is key here. In a normal supplier-manufacturer
relationship, the supplier is not trying to create a product or service with the manufacturer. He is
trying to create a component part for the manufacturer. But here, United Allergy is trying to sell

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a service (allergy testing and allergen immunotherapy) with the PCPs rather than selling a service
or product for the PCPs. That is what distinguishes this case from the traditional Illinois Brick
case, where a consumer might sue a bottle manufacturer because it charged Pepsi supra-
competitive prices for plastic bottles. That is also what prevents my proposed rule from becoming
a “nebulous standard.” Murphy Concurrence at 22. In Judge Murphy’s hypothetical about car
manufacturers, the supplier and the manufacturer would not be in a joint venture because the
supplier is creating a product for the manufacturer, which is then independently using that product
to create the car. By contrast, United Allergy and the PCPs are creating a service together because
they are jointly providing the allergy testing.
The panel reasoned that United Allergy is an indirect seller under Illinois Brick simply
because it sells its services to the PCPs, who then sell their services to patients and insurance
companies. See Amerigroup, 155 F.4th at 814–15. But under the panel’s logic, United Allergy
would have had antitrust standing if the PCPs sold their services to United Allergy, who sold its
services to the insurers. It is hard to understand why a joint venture participant would have
standing in the latter scenario (the PCP selling to United Allergy) but not the former (United
Allergy selling to the PCP). The only difference is the direction in which money flows through
the joint venture.
In substance, United Allergy directly competes with Allergy Associates. Both United
Allergy and Allergy Associates seek patients who need allergy testing and immunotherapy. The
only difference between the two approaches is whether doctors are on staff to provide the medical
services. But either way, United Allergy and Allergy Associates each has unique ways of
attracting patients, the essence of a competitor-competitor relationship.
The Second Circuit dealt with similar practical realities in Crimpers Promotions Inc. v.
Home Box Off., Inc., 724 F.2d 290 (2d Cir. 1983). It held that a member of a joint venture had
antitrust standing to sue two defendants that instigated a group boycott against the joint venture,
even though the plaintiff was not directly injured by the boycott. See id. at 290. The plaintiff tried
to create a joint venture with television executives to run a conference, and HBO and Showtime
allegedly began harassing the executives. Id. at 291. Judge Henry Friendly, writing for a

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unanimous court, observed that the plaintiff “got in the way” of the defendants’ relationships with
the executives, so the defendants “made it suffer for trying to do so.” Id. at 294.
Similar illegal conduct is alleged here. Before United Allergy entered the market, the PCPs
had to refer their patients to Allergy Associates for allergy and immunotherapy treatment. R. 103,
FAC, PageID 2668–70. United Allergy sought to provide the PCPs an alternative, whereby the
PCPs themselves could provide the treatment by using United Allergy’s products and services. Id.
at PageID 2671. United Allergy thus “got in the way” of the Allergy Associates-PCP relationship,
and Allergy Associates is alleged to have made United Allergy “suffer for trying to do so.”
Crimpers Promotions, 725 F.2d at 294; see R. 103, FAC, PageID 2678–2703.
My argument is more nuanced than Judge Murphy understands it to be. See Murphy
Concurrence at 21. My concern with the panel’s formalism is not rooted in the overarching rule
of who may sue for an antitrust violation. As I note below, we both agree that indirect purchasers
cannot sue under Illinois Brick. See infra Part II. Assuming that this is a formalistic rule—a
debatable proposition given the ownership or control exception, see infra Part I.C—my concern is
with the antecedent issue of how to define an indirect purchaser. That is a substantive question
that, like the other substantive questions of Sherman Act liability, should not be answered
formalistically. See McCready, 457 U.S. at 480–81 (applying the pragmatic and market-centric
view I advocate to hold that the plaintiff had antitrust standing).
Even if the panel is correct that United Allergy itself is not a competitor in the relevant
market, I am not confident that this factor alone is enough to deny United Allergy antitrust
standing. In Novell, Inc. v. Microsoft Corp., the Fourth Circuit stated that the Supreme Court had
“rejected” Microsoft’s theory that an antitrust plaintiff must be either a consumer or competitor in
the relevant market. 505 F.3d 302, 311–12 (4th Cir. 2007). Instead, the Fourth Circuit concluded
that other affected entities could bring a Sherman Act claim. Id. at 314. And in Ostrofe v. H.S.
Crocker Co., Inc., the Ninth Circuit recognized antitrust standing of an employee who was
“boycotted from further employment in the industry” for failing to cooperate with the defendant’s
alleged anticompetitive conduct because, although he was not a participant in the market where
the alleged restraint was taking place, he lost his job because of his refusal to help carry out the

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restraint. 740 F.2d 739, 742, 746–47 (9th Cir. 1984). So although the employee was not directly
targeted by the anticompetitive conduct, he suffered a harm from it such that he had standing to
sue. Id. at 743.
C.
My third concern is that the panel opinion reads the Supreme Court’s proximate-cause
precedents more literally than perhaps it should, given the Court’s decisions applying Illinois
Brick. The Court has twice suggested that the mere existence of a corporate entity between the
plaintiff and the defendant would not bar antitrust standing under Illinois Brick.
The first case, California v. ARC America Corp., held that Illinois Brick does not bar suit
“when the direct purchaser is owned or controlled by the indirect purchaser . . . .” 490 U.S. 93, 97
n.2 (1989). The entities contemplated in ARC were functionally “a single entity that bears the
entire overcharge.” Areeda & Hovenkamp ¶ 346f. In such cases, existence of a level of corporate
separateness between the plaintiff and defendant thus would not be enough to defeat the claim.
See In re Sugar Indus. Antitrust Litig., 579 F.2d 13, 18–19 (3d Cir. 1978) (holding that a subsidiary
is inseparable from the parent for Illinois Brick purposes). Similarly, here, the single entity is the
joint venture between United Allergy and a PCP. This business arrangement is, in a sense,
controlled by each entity, for both are necessary for the venture to exist.
The second case, Blue Shield of Virginia v. McCready, held that Illinois Brick will not bar
the suit when “[t]he harm to” the plaintiff “and her class was clearly foreseeable . . . .” 457 U.S.
465, 479 (1982). McCready was a proper antitrust plaintiff because, even though her psychologist
bore the brunt of the anticompetitive harm, McCready’s “injury was ‘inextricably intertwined’
with the intended harm to psychologists” given that it was impossible to harm the psychologists
without also harming McCready. Areeda & Hovenkamp ¶ 339f (quoting McCready, 457 U.S. at
484). Put differently, “[t]he harm to McCready was a necessary step in effecting the ends of the
alleged illegal conspiracy and an integral aspect of the conspiracy alleged.” Ostrofe, 740 F.2d at
745 (quoting McCready, 457 U.S. at 479) (cleaned up). That made McCready’s injury clearly
foreseeable and thus outside the reach of Illinois Brick.

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Likewise, here, United Allergy’s alleged injury was clearly foreseeable. Allergy
Associates knew that United Allergy would face harm because Allergy Associates was trying to
drive United Allergy out of the market. See R. 103, FAC, PageID 2678–79. And the harms to the
PCPs and United Allergy are inextricably intertwined. In much the same way the insurers
boycotted psychologists in McCready precisely because patients like McCready received therapy
from psychologists, the insurance companies here allegedly boycotted the PCPs precisely because
United Allergy worked with them. By driving the PCPs out of the market, Allergy Associates and
the insurance companies necessarily drove United Allergy out of the market as well. Put
differently, the harm to United Allergy was a necessary step in carrying out the group boycott and
an integral aspect of the boycott alleged. My reading of McCready would suggest that this alleged
harm to United Allergy was clearly foreseeable and thus outside the reach of Illinois Brick.
The panel’s rejection of this conclusion rests on what it calls a “clear ‘rule of contractual
privity’” from Apple v. Pepper, 587 U.S. 273 (2019). Amerigroup, 155 F.4th at 815 (quoting
Pepper, 587 U.S. at 289 (Gorsuch, J., dissenting)). Because United Allergy was not in contractual
privity with the insurance companies, it could not recover damages for lost sales. Id.
That is one way to read Pepper’s application of Illinois Brick, but it is not the only way.
Pepper may not set a rule of contractual privity because the majority never frames its decision in
that light—the dissent does. The majority says only that “the absence of an intermediary is
dispositive”—i.e., a plaintiff will always have antitrust standing when there is no one between the
plaintiff and the defendant. Pepper, 587 U.S. at 281. But the fact that a plaintiff will always have
antitrust standing if it is in contractual privity with the defendant (or when no one stands between
them) does not necessarily mean that it will never have antitrust standing if it is not (or when
someone stands between them). Indeed, the McCready plaintiff was a third party to psychologists’
contracts with the insurance companies, so she lacked privity of contract with the defendant
insurers. See McCready, 457 U.S. at 468; 13 Williston on Contracts § 37:1 (4th ed. May 2025
Update).
I suggest that Pepper be read simply to apply McCready’s rule of foreseeability for
proximate cause, not to establish a rule of privity. It was foreseeable that McCready would have

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been harmed by the anticompetitive conduct because, as the psychologists’ patient, she was the
person the insurance companies wanted to coerce into seeing a psychiatrist instead. McCready,
457 U.S. at 479. And the harm to the plaintiffs in Pepper was foreseeable because Apple was
trying to extract the supra-competitive prices from the plaintiffs. See 587 U.S. at 281. In other
words, the harm to a direct purchaser or a plaintiff in contractual privity is foreseeable as a matter
of law. But that does not, of course, exclude the possibility that a defendant could foresee harm to
a plaintiff that lacks contractual privity.3
I am not, as Judge Murphy suggests, calling for an “exception to Illinois Brick.” Murphy
Concurrence at 21. The question in this case is how to characterize two separate business entities
that—in United Allergy’s words—“jointly provide[]” a service in a market. R. 103, FAC, PageID
2671, 2677, 2708. And I am suggesting that those entities should be considered one for Illinois
Brick purposes such that United Allergy would be the direct seller in this case. Adopting my
interpretation of the Illinois Brick rule would not change Illinois Brick’s core holding that indirect
purchasers cannot sue for overcharge damages. At most, it would change how we determine who
the direct and indirect purchasers are.
Nor does my view, as Judge Murphy asserts, conflict with Kansas v. UtiliCorp United,
Inc., 497 U.S. 199 (1990). See Murphy Concurrence at 21. In UtiliCorp, the indirect purchaser
ratepayers were distinct from, and not acting as a single entity in the market with, the direct
purchaser utility companies. See 497 U.S. at 204–05. It says nothing about this case, where two
entities are functioning as one within the relevant market. Moreover, because it was unclear
whether “the direct purchaser” in UtiliCorp “could [] have raised its rates prior to the overcharge,”
there is no way to calculate what the direct purchasers would have charged in a competitive market,
3Judge Murphy’s concurrence diverges from the contractual privity rule that the panel opinion purports to
apply, arguing instead that Pepper “unambiguous[ly]” set a rule that “all direct purchasers from an antitrust defendant
may sue” and “that all indirect purchasers may not sue.” Murphy Concurrence at 22. I agree. But that does not
contradict the more nuanced point that I make—that a layer of corporate separateness between the plaintiff and the
defendant does not deprive the plaintiff of antitrust standing. As noted above, my point is not that indirect purchasers
or sellers can have antitrust standing. Rather, it is that participants in a joint venture can each be deemed a direct
purchaser or seller when that joint venture is the direct purchaser or seller.

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and so on. Id. at 209. That is precisely the problem that the Court identified in Illinois Brick and
precisely the problem that we do not have in a group boycott case. See supra Part I.A.
The operative question, therefore, should be whether the harm to the plaintiff is
foreseeable. The increased prices paid by the indirect purchasers in Illinois Brick were not
foreseeable because the defendants did not know whether the plaintiffs would have to bear those
costs. But here, I think a reasonable person could conclude that United Allergy being forced out
of the market is foreseeable: that is the natural, logical, and intended consequence of a group
boycott allegedly designed to exclude United Allergy from the market.
Judge Murphy misunderstands the nature of the proximate causation inquiry when he
suggests that I want to “replace” it “with a case-by-case foreseeability test.” Murphy Concurrence
at 22. Federal cases involving federally created causes of action, state tort cases, and the secondary
sources almost uniformly characterize proximate causation as a foreseeability question. See, e.g.,
Trollinger v. Tyson Foods, Inc., 370 F.3d 602, 615 (6th Cir. 2004); D.J. ex rel. R.J. v. First Student,
Inc., 707 S.W.3d 581, 586–87 (Mo. 2025) (en banc), reh’g denied (Apr. 1, 2025); Werner Enters.,
Inc. v. Blake, 719 S.W.3d 525, 532 (Tex. 2025), reh’g denied (Sept. 26, 2025); Osborne v. Atl. Ice
& Coal Co., 177 S.E. 796, 796–97 (N.C. 1935); 65 C.J.S. Negligence § 209 (Dec. 2025 Update);
57A Am. Jur. 2d Negligence §§ 393, 448 (Nov. 2025 Update). So rather than replacing proximate
causation with a case-by-case foreseeability test, I am simply returning to the core of the
proximate-causation question that the Court confronted in McCready—whether the harm alleged
is foreseeable. That is how we reconcile Illinois Brick, which said that there must be a direct
buyer/seller relationship between the plaintiff and the defendant, and McCready, where the
plaintiff was neither the buyer nor the seller in the unlawful restraint. And United Allergy’s claims
fit neatly within this framework because, as a participant in the joint venture that was targeted by
the boycott, the harms to it were a necessary and clearly foreseeable result of Allergy Associates’
conduct.
Judge Murphy may be correct that “in the RICO context, the focus is on the directness of
the relationship between the conduct and the harm,” but “the concepts of direct relationship and
foreseeability are of course two of the many shapes proximate cause took at common law.” Hemi

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Grp., LLC v. City of New York, 559 U.S. 1, 12 (2010) (quoting Holmes v. Sec. Inv. Prot. Corp.,
503 U.S. 258, 268 (1992)) (cleaned up). And even if the Court has rejected foreseeability in the
RICO context, it has expressly adopted it for cases arising under the Sherman Act. McCready,
457 U.S. at 479 (“The harm to McCready and her class was clearly foreseeable; indeed, it was a
necessary step in effecting the ends of the alleged illegal conspiracy.”).
D.
Finally, the Court may wish to review this case because the panel applied Illinois Brick to
a suit for an injunction.4 The standing analysis for damages and injunction plaintiffs “will not
always be identical.” Cargill, Inc. v. Monfort of Colo., Inc., 479 U.S. 104, 111 n.6 (1986). Unlike
a damages plaintiff, an injunction plaintiff needs to show only that it has suffered antitrust injury;
proximate causation does not come into play. See id. The bar is much lower for injunction
plaintiffs because “one injunction is as effective as 100, and, concomitantly . . . 100 injunctions
are no more effective than one,” which eliminates the problems from duplicative liability in a
damages suit. Hawaii v. Standard Oil Co. of Cal., 405 U.S. 251, 261 (1972).
Textually, that makes sense. Clayton Act § 4 provides a damages remedy for “any person
who shall be injured in his business or property by reason of anything forbidden in the antitrust
laws . . . .” 15 U.S.C. § 15(a) (emphasis added). By contrast, Clayton Act § 16 lets a plaintiff seek
an injunction “against threatened loss or damage by a violation of the antitrust laws . . . .” Id. § 26.
4That the injunction issue was not raised until United Allergy’s petition for rehearing en banc would not have
precluded our consideration of that issue had we granted en banc review. “Generally, an argument not raised in an
appellate brief or at oral argument may not be raised for the first time in a petition for rehearing.” Costo v. United
States, 922 F.2d 302, 302–03 (6th Cir. 1990). That “rule is not, however, absolute,” and courts “may choose to
entertain a new argument on rehearing if ‘extraordinary circumstances’ are present.” United States v. Shafer, 573 F.3d
267, 276 (6th Cir. 2009) (quoting Easley v. Reuss, 532 F.3d 592, 594 (7th Cir. 2008)). For example, courts are more
willing to overlook the failure to raise the issue when (1) it is not “willful” or strategic and (2) the argument raised for
the first time on rehearing “goes to the heart of” the court’s “initial holding . . . .” Id. at 277.
This case meets those criteria. First, there is no sign that United Allergy strategically or willfully failed to
assert the injunction issue until the petition. When the district court dismissed the action for lack of antitrust injury,
it did not address causation, so there was no reason to address causation in the parties’ principal briefs. Only after the
panel decided to resolve this case on a different ground from the district court did the injunction issue come into play.
Second, the argument raised in the petition goes to the core of the panel’s original holding. If the petition is correct
that Illinois Brick does not apply to suits for injunctions, then the panel’s holding would conflict with Supreme Court
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The broader language in § 16, along with the lack of an explicit causation requirement, suggests
that many requirements from Illinois Brick do not apply to suits for an injunction.
This is why other circuits have said that Illinois Brick cannot bar suits for an injunction.
See, e.g., Mosaic Health, Inc., 156 F.4th at 80; Or. Laborers-Emps. Health & Welfare Tr. Fund v.
Philip Morris Inc., 185 F.3d 957, 966 (9th Cir. 1999); McCarthy v. Recordex Serv., Inc., 80 F.3d
842, 856 (3d Cir. 1996). Those courts have recognized that “standing under Section 16” of the
Clayton Act “raises no threat of multiple lawsuits or duplicative recoveries,” so “Illinois Brick
does not apply” to them. Mosaic Health, Inc., 156 F.4th at 80; see also Mid-West Paper Prods.
Co. v. Cont’l Grp., Inc., 596 F.2d 573, 593–94 (3d Cir. 1979).5
E.
Despite my reservations, I can understand why the court reached the decision it did. The
Supreme Court has imposed a proximate causation requirement on all federal causes of action.
Lexmark Int’l, Inc. v. Static Control Components, Inc., 572 U.S. 118, 132–33 (2014). Proximate
causation “bars suits for alleged harm that is too remote from the defendant’s unlawful conduct,”
which “is ordinarily the case if the harm is purely derivative of misfortunes visited upon a third
person by the defendant’s acts.” Id. at 133 (quoting Holmes v. Secs. Inv. Prot. Corp., 503 U.S.
258, 268–69 (1992)) (quotation marks omitted). Under at least one reading of the FAC, United
Allergy is seeking redress that is “purely derivative of misfortunes visited upon a third person by
the defendant’s acts.” Id.
That reading, however, may not do full justice to the allegations. At the Rule 12(b)(6)
stage, we are supposed to read the complaint liberally to infer liability whenever such an inference
is plausible. See, e.g., Royal Truck & Trailer Sales & Serv., Inc. v. Kraft, 974 F.3d 756, 758 (6th
5To the extent Judge Murphy asserts “that the panel resolved th[is] issue on forfeiture grounds,” Murphy
Concurrence at 23, I would note that the panel opinion makes no such holding. Additionally, we give the panel an
opportunity to amend its decision prior to circulating the petition for rehearing en banc to the full court for en banc
consideration, see 6th Cir. I.O.P. 40(b)(4)(A), and the panel made no such amendment here. Thus, to the extent that
Allergy Associates seeks to assert that United Allergy has forfeited review of this question before the Supreme Court,
it is worth noting that: (1) the panel opinion that would be subject to certiorari review does not hold the issue forfeited,
(2) forfeiture can itself be forfeited, see Garza v. Idaho, 586 U.S. 232, 238–39 (2019), and (3) Allergy Associates did
not argue that this issue was forfeited in its principal briefing.

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Cir. 2020). And such a liberal interpretation of the pleadings may suggest that United Allergy
suffered a direct, foreseeable injury as a competitor of Allergy Associates and a target of its
allegedly unlawful conduct.
The FAC alleges that Allergy Associates organized a per se unlawful boycott. R. 103,
FAC, PageID 2665. By convincing the insurers to refuse to pay for claims made by United
Allergy’s PCPs, Allergy Associates “deprive[d]” a “would-be competitor[] of a trade relationship”
that it needs “in order to enter (or survive in)” the allergy testing market. PLS.Com, LLC v. Nat’l
Ass’n of Realtors, 32 F.4th 824, 834 (9th Cir. 2022) (quoting Smith v. Pro Football, Inc., 593 F.2d
1173, 1178 (D.C. Cir. 1978)); see also Nw. Wholesale Stationers, Inc. v. Pac. Stationery &
Printing Co., 472 U.S. 284, 294 (1985). According to the FAC, Allergy Associates knew its fraud
claims were unfounded, and Allergy Associates had been lobbying for years to keep United
Allergy out of the market before turning to the boycott. R. 103, FAC, PageID 2679–81. If United
Allergy’s allegations are true, this case would appear to be a clear example of an unlawful boycott.
See Amerigroup, 155 F.4th at 829 (Kethledge, J., concurring).
II.
As Judge Kethledge recognized, the panel opinion may be a major blow to patients and
providers in Tennessee. Thanks to United Allergy’s competition, “rates came down, access to
these services became more convenient, and more patients actually obtained them.” Amerigroup,
155 F.4th at 828 (Kethledge, J., concurring). But then, the “defendants successfully conspired to
eject a new and more efficient supplier from a market that had been badly undersupplied before,”
requiring patients again to pay the price of “travelling hundreds of miles to clinics run by a single
medical practice.” Id. at 829. Not only that, many joint-venture participants may have less
antitrust protection in our circuit. If one participant is “closer” to the defendant than the other,
then only that one participant can seek redress for the harms.6 And if the closer participant cannot
or does not want to sue, then the rest of the joint venture is out of luck.
6Recall that, at least in Tennessee, a joint venture will never be a single legal entity because it cannot be “a
partnership in the legal or technical sense of the term . . . .” Fain, 909 S.W.2d at 793.

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Ultimately, though, this case does not warrant en banc review. The panel opinion is a
reasonable interpretation and application of the Supreme Court’s precedent. Our decision whether
to grant en banc review may be analogized to how we conduct habeas review under the
Antiterrorism and Effective Death Penalty Act of 1996 (AEDPA), Pub. L. No. 104-132, 110 Stat.
1214. Under AEDPA, we will not disturb a state court’s ruling unless it is “contrary to, or involved
an unreasonable application of, clearly established Federal law, as determined by the Supreme
Court of the United States,” even though we might be inclined to rule differently if we were
reviewing the case in the first instance. Hodge v. Plappert, 136 F.4th 648, 658 (6th Cir. 2025) (en
banc), cert. denied, No. 25-6179 (U.S. Jan. 12, 2026) (quoting 28 U.S.C. § 2254(d)(1)); see also
Randolph v. Macauley, 155 F.4th 859, 871 (6th Cir. 2025). We should use a similar standard in
the en banc process to assess our colleagues’ view of Supreme Court precedent. If we second-
guess our colleagues because we might have adopted the other of two competing and equally
reasonable interpretations of the Supreme Court’s case law, then there would be little point in using
panels to decide cases at all.
Indeed, the narrow nature of my disagreement with Judge Murphy (and the panel opinion)
highlights why we should avoid second-guessing each other by routinely taking cases en banc.
We agree with the core premises that (1) the rules governing monopsonies and monopolies are the
same,7 (2) Illinois Brick imposes a bright-line rule barring suits by indirect purchasers,8 and (3) a
supplier to a seller that works directly with the monopsonist is normally an indirect seller under
Illinois Brick.9 Our disagreement focuses only on whether participants in a joint venture should
be treated as one actor in the relevant market or two when determining whether the participants
are indirect sellers under Illinois Brick.
7See Murphy Concurrence at 19; Acad. of Allergy & Asthma in Primary Care v. Amerigroup Tenn., Inc., 155
F.4th 795, 813 (6th Cir. 2025); Weyerhaeuser Co. v. Ross-Simmons Hardwood Lumber Co., 549 U.S. 312, 321–22
(2007).
8See Murphy Concurrence at 19; Amerigroup, 155 F.4th at 813; Pepper, 587 U.S. at 280.
9See Murphy Concurrence at 1; Amerigroup, 155 F.4th at 813; Zinser v. Cont’l Grain Co., 660 F.2d 754, 760
(10th Cir. 1981).

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In our circuit, granting rehearing en banc effectively throws out all of the work that the
panel has done on the case. See 6th Cir. Local Rule 40(d). In cases like this, where the scope of
disagreement is narrow and the panel’s decision is at least reasonable, we should not normally
rehear a case en banc. Because the Supreme Court can narrow a grant of certiorari to focus on that
core issue without vacating the entire, potentially correct, panel decision, see, e.g., Willis of
Colorado Inc. v. Troice, 568 U.S. 1140 (2013), we should generally leave it to that higher court to
correct any errors in the panel’s reasoning.
Given the disharmony in the application of Illinois Brick in the lower courts, and for other
reasons discussed above, this case may be appropriate for Supreme Court review, though. The
Court may wish to clarify the application of Illinois Brick in the context of an alleged group boycott
of a business arrangement that essentially functions as a joint venture.

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__________________
CONCURRENCE
__________________
MURPHY, Circuit Judge, with whom SUTTON, Chief Judge, and KETHLEDGE, Circuit
Judge, join, concurring in the denial of rehearing en banc. Congress has granted a cause of action
to “any person who shall be injured in his business or property by reason of anything forbidden in
the antitrust laws[.]” 15 U.S.C. § 15(a). In Illinois Brick Co. v. Illinois, 431 U.S. 720 (1977), the
Supreme Court read the phrase “by reason of” to adopt a “bright-line rule” of proximate causation.
Apple Inc. v. Pepper, 587 U.S. 273, 279 (2019) (quoting 15 U.S.C. § 15(a)). Under this rule,
“direct purchasers” (those who buy a product from antitrust-violating sellers) may sue the sellers.
Id. at 280. But “indirect purchasers who are two or more steps removed from the antitrust
violator[s] in a distribution chain may not sue.” Id. And the circuit courts all agree that this rule
applies in the opposite direction. See Acad. of Allergy & Asthma in Primary Care v. Amerigroup
Tenn., Inc., 155 F.4th 795, 813 (6th Cir. 2025). That is, direct sellers who sell to antitrust-violating
purchasers may sue the purchasers, but indirect sellers who are “two or more steps removed” from
those purchasers may not. Apple, 587 U.S. at 280. The rule thus bars United Allergy’s suit in this
case because it sells products and services to primary-care physicians who, in turn, sell to the
alleged antitrust-violating insurers. See Acad. of Allergy & Asthma, 155 F.4th at 814–20.
In his statement respecting the denial of rehearing en banc, Judge Bush finds this holding
debatable on four fronts. With respect for my colleague, I do not find the holding particularly
debatable. As Judge Kethledge noted, the Supreme Court can depart from Illinois Brick’s rule if
it sees fit to do so. See Acad. of Allergy & Asthma, 155 F.4th at 828 (Kethledge, J., concurring).
But such a change must come from that Court, not this one.
First, Judge Bush asserts that Illinois Brick’s rule should apply only to a plaintiff who seeks
an illegal overcharge and alleges a horizontal price cartel—not to a plaintiff who seeks lost profits
and alleges a group boycott. Start with the substantive theory of the antitrust violation. We
typically do not interpret a statutory phrase like “by reason of” (the language that codifies the
Illinois Brick rule) as a “chameleon” that changes its meaning based on the factual circumstances.

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15 U.S.C. § 15(a); Clark v. Martinez, 543 U.S. 371, 382 (2005). So I do not see how this language
can prohibit indirect sellers from suing if they allege a downstream horizontal cartel that harms
both direct and indirect sellers, but also permit indirect sellers to sue if they allege a downstream
group boycott of direct and indirect sellers. Under either theory, the indirect sellers are still
indirect. And, as far as I am aware, no circuit court has interpreted the language in this way—as
the panel explained. See Acad. of Allergy & Asthma, 155 F.4th at 816.
Turn to the requested damages. Like the Third Circuit, I find it unlikely that the Supreme
Court would retain Illinois Brick’s rule but transform it into a mere “pleading” limit that plaintiffs
can readily avoid by seeking lost profits rather than overcharge (or, as here, undercharge) damages.
Id. at 815, 817 (citing Howard Hess Dental Labs. Inc. v. Dentsply Int’l, Inc., 424 F.3d 363, 376
(3d Cir. 2005)). Again, how can an indirect seller’s lost profits arise “by reason of” an antitrust
violation while the indirect seller’s overcharge or undercharge damages cannot? Here, moreover,
at least one doctor separately sued to recover “the entire undercharge” (the full amount of
unreimbursed claims). Id. at 814. He was seemingly entitled to ask for this amount under the
complementary rule from Hanover Shoe, Inc. v. United Shoe Machinery Corp., 392 U.S. 481
(1968), which prohibits courts from reducing a direct victim’s damages by the amount passed on
to others. So if Illinois Brick does not apply here, then Hanover Shoe cannot apply in suits by the
directly injured doctors. Cf. Apple, 587 U.S. at 298 (Gorsuch, J., dissenting). Otherwise, direct
and indirect victims could obtain double recovery over the same harm. In other words, a court
must either grant overcharge and undercharge damages to directly injured parties or limit all parties
to their lost profits. It cannot do both.
For what it is worth, if the Court does consider this question, it should consider which is
the proper remedy. Some view lost profits as appropriate damages. See Howard Hess, 424 F.3d
at 374–75. But others have cautioned that a lost-profits remedy represents a poor measure of the
harm from antitrust violations. See id. at 375 (discussing Frank H. Easterbrook, Treble What?, 55
Antitrust L.J. 95, 96–97, 100–01 (1986)). For example, Medicaid markets are unusual ones in
which the government itself sets reimbursement rates (and hence prices). So a lost-profits remedy
might overcompensate plaintiffs if their profits arise not from their superior services but from the
government’s mistaken pricing of isolated services at levels above their costs.

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Second, Judge Bush asserts that the panel opinion’s formalist view conflicts with the
Supreme Court’s “pragmatic view” of the antitrust laws. But this claim mistakes the substantive
standards of antitrust liability in 15 U.S.C. § 1 for the procedural standards over who can sue for
violations in 15 U.S.C. § 15(a). Yes, when identifying the agreements that qualify as illegal
“restraint[s] of trade,” 15 U.S.C. § 1, the Supreme Court has looked to “demonstrable economic
effect” and avoided “formalistic line drawing”—as the Court well explained in Leegin Creative
Leather Products, Inc. v. PSKS, Inc., 551 U.S. 877, 885‒87 (2007) (quoting Cont’l T.V., Inc. v.
GTE Sylvania Inc., 433 U.S. 36, 49, 58‒59 (1977)). The Court reached this result, in part, because
it interpreted the phrase “restraint of trade” as codifying a common-law process that can evolve
with business conditions. See id. at 887–88. But the panel opinion assumed that United Allergy
alleged violations of the antitrust laws. Acad. of Allergy & Asthma, 155 F.4th at 806.
This case instead addresses a different question: who may sue for violations? That question
implicates a separate statute. As I have said, Congress has granted a cause of action to “any person
who shall be injured in his business or property by reason of anything forbidden in the antitrust
laws[.]” 15 U.S.C. § 15(a). And when interpreting this different text, the Court has taken a
formalistic approach. Indeed, the Court in Apple noted that Illinois Brick adopted a “bright-line
rule” some six times. See Apple, 587 U.S. at 279–82, 285. The Court has stuck to this formalistic
rule even when it made little economic sense—such as the case of regulated public utilities that
“pass on 100 percent of their costs to their customers.” Kansas v. UtiliCorp United, Inc., 497 U.S.
199, 208 (1990). “[E]ven assuming that any economic assumptions underlying the Illinois Brick
rule might be disproved in a specific case,” the Court reasoned, “we think it an unwarranted and
counterproductive exercise to litigate a series of exceptions.” Id. at 217. And once a court
concludes that Illinois Brick should apply not just when buyers sue sellers but also when sellers
sue buyers (a fact that seemingly nobody disputes), its rule applies here.
Perhaps the Court will carve out Judge Bush’s “joint venture” exception to Illinois Brick.
But its refusal to create an exception for regulated public utilities leads me to conclude that we
cannot. Indeed, the Seventh Circuit has refused to create an exception even when an indirect-
purchaser parent owns the direct-purchaser subsidiaries. Motorola Mobility LLC v. AU Optronics
Corp., 775 F.3d 816, 821–22 (7th Cir. 2015) (Posner, J.). And many entities could claim that they

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are engaged in a joint venture. Most distribution chains have multiple downstream suppliers. If a
car manufacturer buys a large part from one supplier and that part has many components sold by
others, why couldn’t the car manufacturer claim it was in a joint venture with the part supplier and
sue over a price cartel involving one of the components? In short, the proposed exception might
well turn Illinois Brick’s “bright-line rule” into a nebulous standard. Apple, 587 U.S. at 279.
Third, Judge Bush would replace Illinois Brick’s “bright-line rule” of proximate causation
with a case-by-case foreseeability test. Id. He reads Apple as holding that all direct purchasers
from an antitrust defendant may sue but not necessarily the converse: that all indirect purchasers
may not sue. I find Apple unambiguous. It repeatedly indicated that its rule meant not just that
“direct purchasers” may sue but also that “indirect purchasers” may not. Id. at 279, 280, 282, 285.
And as the panel explained, United Allergy does not sit in the middle of a two-sided market with
directly contracting parties on both sides. See Acad. of Allergy & Asthma, 155 F.4th at 813–14,
818–19. So this case resembles neither Apple nor Blue Shield of Virginia v. McCready, 457 U.S.
465 (1982). See Acad. of Allergy & Asthma, 155 F.4th at 813–14, 818–19.
Nor can we as a lower court jettison Illinois Brick’s bright-line rule in favor of the general
foreseeability test that Judge Bush proposes. That test “would nullify the doctrine of Illinois
Brick.” Motorola, 775 F.3d at 822. Price fixers can almost always foresee that their illegal conduct
will affect not just their direct purchasers but also downstream purchasers. See id. Yet the
Supreme Court has sometimes even refused to allow the intended victims of antitrust violations to
sue—even though that harm is, by definition, foreseeable. See Associated Gen. Contractors v.
Cal. State Council, 459 U.S. 519, 529 (1983). That is because the Court has long treated the
directness of the injury and the foreseeability of the injury as independent proximate-causation
requirements. See Hemi Grp., LLC v. City of New York, 559 U.S. 1, 12 (2010). And the Illinois
Brick rule arises out of the directness (not the foreseeability) part of proximate causation.
Fourth, Judge Bush asserts that the panel opinion created a circuit conflict over a question
about who may seek injunctive relief. But United Allergy has forfeited its belated suggestion that
different standards should apply to a request for injunctive relief than a request for damages. The
district court dismissed United Allergy’s antitrust claims without mentioning that the company

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had sought injunctive relief or the separate cause of action for that relief: 15 U.S.C. § 26. See
generally United Biologics, LLC v. Amerigroup Tenn., Inc., 2022 WL 22897162 (E.D. Tenn. Jan.
27, 2022). In its opening brief on appeal, United Allergy stated that it had sought “injunctive
relief” in its procedural background, but it never argued that distinct standards should apply to that
relief. Appellant’s Br. 22. Nor did United Allergy cite (let alone interpret the text of) the separate
cause of action that authorizes this relief. United Allergy instead asserted that it had stated a cause
of action under “Section 4 of the Clayton Act” (namely, 15 U.S.C. § 15). Appellant’s Br. 26. It
also did not use the word “injunction” or mention the cause of action for this relief (15 U.S.C.
§ 26) in its reply brief or in the supplemental brief that we requested. If parties forfeit (or even
waive) arguments not raised in their opening briefs, see Kuhn v. Washtenaw County, 709 F.3d 612,
624 (6th Cir. 2013), they certainly forfeit arguments not raised until a petition for rehearing en
banc. (The panel opinion itself, of course, could not have expressly articulated this forfeiture
finding because United Allergy did not raise this argument until the rehearing stage.)
As a result, I do not view the panel opinion as resolving any questions related to injunctive
relief on the merits. In particular, it did not address whether the language in 15 U.S.C. § 26
(“threatened loss or damage by a violation of the antitrust laws”) has a different causal scope than
the language in 15 U.S.C. § 15 (“injured in his business or property by reason of anything
forbidden in the antitrust laws”). Nor did the panel depart from other circuit courts that have
proposed more relaxed standards for § 26’s cause of action. Perhaps there are good reasons to
extend Illinois Brick’s rule to the injunction context because that rule flows out of the proximate-
causation requirement that the Court presumptively reads into all private rights of action. See
Apple, 587 U.S. at 291 n.1 (Gorsuch, J., dissenting). But that question must await a case in which
the parties litigate it. So if, as Judge Bush says, the Supreme “Court may wish to review” this
injunction issue, it should recognize that the panel resolved that issue on forfeiture grounds (not
the merits). And the proper standards for injunctive relief remain open in our court.
* * *
United Allergy also implies that the panel resolved this case on a ground that the defendants
did not preserve, pointing out that they did not cite Illinois Brick in their original briefing. But

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parties raise and preserve arguments—not case citations. And the defendants advocated for Illinois
Brick’s direct-injury element under what appeared to be our ad hoc balancing test for antitrust
standing. See Acad. of Allergy & Asthma, 155 F.4th at 807. But, as the panel explained, our test
is better read as asserting two distinct elements rather than a jumble of factors: that the plaintiff
suffered an antitrust injury and that the defendants proximately caused that injury. See id. at 807–
08. The district court’s opinion found that United Allergy did not satisfy either element. So Judge
Bush is mistaken to suggest that the court dismissed this case solely for lack of antitrust injury.
The court held that the company did not compete in the relevant market (and so had not pleaded
an antitrust injury). See United Biologics, 2022 WL 22897162, at *5–7. And it held that United
Allergy was not directly injured (and so had not pleaded proximate cause). See id. at *8–9. The
defendants on appeal likewise raised both arguments—even before we asked for supplemental
briefing on how Illinois Brick fits into that framework. See, e.g., Appellee’s Br. of Amerigroup
Tenn., Inc., at 26–33, 35–41 (antitrust injury); id. at 33–35, 41–43 (indirect injury).
Ultimately, the panel opted to resolve this appeal based on Illinois Brick’s “bright-line”
direct-injury rule. Apple, 587 U.S. at 279. If the Supreme Court means to replace that rule with
an “open-ended balancing test[],” it can tell us. Lexmark Int’l, Inc. v. Static Control Components,
Inc., 572 U.S. 118, 136 (2014). Until it does, I would follow its decisions to their logical
conclusions. On this understanding, I concur in the denial of rehearing en banc.
ENTERED BY ORDER OF THE COURT
____________________________________
Kelly L. Stephens, Clerk

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