               FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


WILLIAMS MICHAEL HICKS;            No. 16-15370
KENNETH HARMS, as Class
Representative Plaintiffs and         D.C. No.
Individual Plaintiffs; MATTHEW   3:15-cv-00489-VC
ACHATZ; BRANDON ANTUS;
CHAD ANTUS; ANDREW BARNES;
CHRIS BERRY; MICHAEL BESTOR;        OPINION
DUANE BOCK; DAVID BROOKER;
MARK CARNES; STEVEN CATLIN;
BRUCE CLENDENEN; GRAEME
COURTS; MICHAEL DARBY;
HENRY DIANA; DON DONATELLO;
MICHAEL DORAN; JAMES
EDMONDSON; DEAN ELLIOTT;
JOSEPH ETTER; BRENT EVERSON;
MICAH FUGITT; DAMON GREEN;
JAY HAAS, JR.; STEVEN HALE;
MATTHEW HAUSER; ADAM
HAYES; WILLIAM HEIM;
JONATHAN JAKOVAC; TOM JANIS;
JIMMY JOHNSON; CHRIS JONES;
NICK JONES; STEVE KAY;
ANTHONY KNIGHT; SHAY
KNIGHT; MITCH KNOX; KURTIS
KOWALUK; RONALD LEVIN; JOHN
LIMANTI; BRENNEN LITTLE;
SCOTT MARTIN, Esquire,
Attorney; RICH MAYO, JR.;
DANIEL MCQUILKEN; ERIC
2              HICKS V. PGA TOUR

MELLER, Esquire, Attorney;
MATTHEW MINISTER; CHARLES
MOHR; TODD MONTOYA; TONY
NAVARRO; DONALD NELSON;
TRAVIS PERKINS; JOSEPH
PYLAND; BRIAN REED; CHAD
REYNOLDS; MIGUEL RIVERA;
DAVID ROBINSON; SCOTT
SAJTINAC; ANDREW SANDERS;
FRED SANDERS; CORBY SEGAL;
SHAWN SEGARS; BRIAN SMITH;
RUSSEL STARK; BRAD
SWEARINGEN; PAUL TESORI;
ROBERT THOMPSON; SCOTT
TWAY; STEVE UNDERWOOD;
MARK URBANEK; RUSTY URESTI;
BRETT WALDMAN; NEIL
WALLACE; AARON WARK;
JEFFERY WILLETT; BARRY
WILLIAMS; MICHAEL MAZZEO;
JOHN YARBROUGH; JUSTIN YORK;
DENNIS TURNING; STEPHEN
WILLIAMS; TERRY R. ENGLEMAN;
THOMAS FLETCHER; ALAN BOND;
EDWARD E. WILLIS; ROBERT J.
MCFADDEN; PETER AMBROSETTI;
KENNETH A. TOLLES; JOSEPH
DUPLANTIS; BRADLEY WHITTLE;
PETER JORDAN; WESTON SCOTT
WATTS; JOSHUA E. DICKINSON;
DAVID B. PARSONS; PETER
VANDERRIET; MARK CRUNDEN;
JOHN M. BUCHNA; COLIN BYRNE;
               HICKS V. PGA TOUR   3

LINN STRICKLER; CHAD
ROSENAK; MATTHEW
BEDNARSKI; MARTIN COURTOIS;
KENNY BUTLER; JEFF DOLF;
MARCEL LABAS; RUSSELL
CRAVER; JAMES WALTERS; JAMES
SMITH; PATRICK V. ESWAY, JR.;
MARK HUBER; JON CUSTER;
LEWIS B. PULLER III; JIM
THOMAS; MARK E. MILLER,
Esquire, Attorney; MATTHEW
HALL; ERIC SCHWARZ; JOHN R.
ADCOX; JOHN VENN; JOHN EGAN;
MATTHEW TRITTON; JAMES
SPRINGER, Esquire, Attorney;
TERRY TRAVIS; RICHARD J.
MOTACKI; ROBERT DICKERSON;
TIM GOODELL; ROBERT VAIL;
TODD NEWCOMB; GREG W.
MARTIN; NOAH ZELNIK; BRENT
HENLEY; CHRISTOPHER S.
FIEDLER; PHILIP LOWE; DAVID
PATTERSON; KEVIN MCARTHUR;
RICHARD M. SCHLAACK; DAVID
H. RAWLS; BOB BURNS; MICHAEL
J. WAITE; HARRY BROWN; DAVID
A. KERR; BRIAN H. SULLIVAN;
ANDREW DAVIDSON; ALLAN
MELLAN; DAVID WOOSLEY;
RONALD MCCANN; DANIEL
SCHLIMM; STEVE GREENWOOD;
ANTHONY WILDS; MICHAEL
MARONEY; ANDREW MARTINEZ;
4                    HICKS V. PGA TOUR

KYLE KOLENDA; DAVID LAWSON;
JOHN L. SMITH; MICHAEL
MIDDLEMO; SPENCER SEIFERT;
LADDEN CLINE; THOMAS G.
WILLIAMS; MICHAEL CARRICK;
CALVIN HENLEY; GEORGE
ASSANTE; WALTER WORTHERN,
JR.; TIMOTHY J. THALMUELLER;
WILLIAM POORE; NORMAN R.
BLOUNT, JR.; WILLIAM SPENCER;
MARK HAMILTON; CHRISTIAN
HEATH HOLT; DAMIAN LOPEZ,
            Plaintiffs-Appellants,

                v.

PGA TOUR, INC.,
            Defendant-Appellee.


      Appeal from the United States District Court
        for the Northern District of California
       Vince Chhabria, District Judge, Presiding

        Argued and Submitted October 12, 2017
              San Francisco, California

                     Filed July 27, 2018
                        HICKS V. PGA TOUR                                5

Before: Sidney R. Thomas, Chief Judge, and Michael Daly
  Hawkins and Kathleen M. O’Malley,* Circuit Judges.

                 Opinion by Chief Judge Thomas


                            SUMMARY**


                               Antitrust

    The panel affirmed in part and vacated in part the district
court’s dismissal of antitrust and related state law claims of
professional golf caddies who participate in golf tournaments
run by the PGA Tour, arising out of the Tour’s requirement
that the caddies wear bibs containing advertisements at
professional golfing events.

    The panel held that the district court was not required to
convert the Tour’s Fed. R. Civ. P. 12(b)(6) motion to dismiss
to a summary judgment motion because the court did not
consider any material outside the pleadings.

    The panel held that the district court properly concluded
that the caddies had consented to wearing the bibs, based on
the text of a tournament participation form, considered with
the caddies’ concession that the Tour had required them to


    *
      The Honorable Kathleen M. O’Malley, United States Circuit Judge
for the U.S. Court of Appeals for the Federal Circuit, sitting by
designation.
    **
       This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
6                   HICKS V. PGA TOUR

wear bibs for decades. The district court also did not err in
concluding that the caddies failed to allege plausibly that the
Tour secured their consent through economic duress. The
caddies therefore failed to state claims for breach of contract
and quasi-contract relief, California state law publicity
claims, a Lanham Act false endorsement claim, or a plausible
economic duress claim.

    The panel held that the district court properly determined
that the caddies had not alleged plausible product markets to
support their antitrust claims. The panel held that, even if
advertisements to golf fans constituted a unique product
market, “in-play” or “in-action” advertising during
professional golf tournaments—either in any format or
endorsements alone—did not constitute a unique submarket.
Agreeing with other circuits, the panel concluded that the
caddies’ proposed product markets were facially
unsustainable because they failed to include many reasonably
interchangeable products.

    The panel held that the district court therefore correctly
dismissed the caddies’ antitrust claims, as well as their
California unfair competition claim. The panel, however,
vacated the dismissal with prejudice of these claims because
the district court made a simple denial of leave to amend
without adequate explanation. The panel remanded for the
district court to reconsider its decision to deny the caddies
leave to amend the antitrust and unfair competition claims.
                    HICKS V. PGA TOUR                        7

                         COUNSEL

Arthur R. Miller (argued), The Lanier Law Firm P.C., New
York, New York; Benjamin T. Major (argued), Kevin P.
Parker, Richard D. Meadow, and W. Mark Lanier, The Lanier
Law Firm P.C., Houston, Texas; for Plaintiffs-Appellants.

Jeffrey A. Mishkin (argued) and Anthony Dreyer, Skadden
Arps Slate Meagher & Flom LLP, New York, New York;
Raoul D. Kennedy, Skadden Arps Slate Meagher & Flom
LLP, Palo Alto, California; for Defendant-Appellee.


                         OPINION

THOMAS, Chief Judge:

    This appeal concerns various antitrust and related state
law claims of professional golf caddies (“Caddies”) who
participate in golf tournaments run by the PGA Tour (“the
Tour”) arising out of the Tour’s requirement that they wear
bibs containing advertisements at professional golfing events.
The district court dismissed all claims with prejudice. We
affirm the dismissal, but remand the case to allow the district
court to reconsider whether to grant the Caddies leave to
amend their federal antitrust and California unfair
competition claims.

                               I

   Henry Longhurst, the renowned British golf writer and
commentator, once wrote: “A good caddie is more than a
mere assistant. He is a guide, philosopher, and friend.” The
professional caddie has evolved from simply carrying bags
8                    HICKS V. PGA TOUR

and locating errant shots to providing valuable insights on
course topography, club selection, and reading shots.
Caddies serve as coaches, strategists, and counselors to
professional golfers.

     The Tour operates three tours of professional golf
tournaments throughout the United States. It requires caddies
to wear specified uniforms at the tournaments, including a
“bib”—a loose-fitting sleeveless garment on the upper body
used for identification. For each tournament, the Tour
generally works with a local host (“Local Host”). The Local
Hosts and Tour seek to secure and retain sponsors, including
title sponsors for the tournaments. Sponsors pay Local Hosts
and the Tour to secure advertising space at the tournaments.
At issue in this case is the advertising space on the bibs worn
by the Caddies during the tournaments.

    Local Hosts and the Tour design the bibs. The bibs bear
a tournament logo and sponsors’ logos, which are often
integrated together. With exposure to live tournament,
television, and webcast audiences, advertising space on the
bibs is valued at approximately $50 million annually. Local
Hosts and the Tour receive the entirety of these revenues.
The Caddies receive none.

    Although individual professional golfers employ the
Caddies as independent contractors, the Tour and Local Hosts
require the Caddies to wear the bibs. The Caddies must sign
a Caddie Registration and Regulations Form (“the Form”) in
order to participate in any Tour tournament. The Form notes
that “[i]n consideration of PGA TOUR’s services in
cosponsoring the Tournament,” the Caddies “grant and assign
to PGA TOUR, without limitation, [their] individual
television, radio, motion picture, photographic, electronic, . . .
                    HICKS V. PGA TOUR                      9

and all other similar or related media rights with respect to
[their] participation in the Tournament.”

   The Form also provides a list of regulations that the
Caddies must adhere to, which in relevant part state:

       2.     Caddies shall wear uniforms and
       identification badges as prescribed by the host
       tournament and PGA Tour. All caddies are
       required to wear solid-colored, Khaki-style
       long pants, which touch the top of the shoe, or
       solid-colored, knee-length, tailored shorts or
       skorts and a collared shirt while on club
       property. T-shirts, jeans, culottes, skirts,
       capris, cut-off shorts and cargo-style shorts
       are not permitted. Acceptable colors shall be
       determined at the discretion of the
       Tournament Director.

       3. Caddies shall wear smooth rubber-sole
       shoes, preferably tennis or basketball shoes.
       Permissible colors are limited to white and
       earth tones such as navy, blue, black, brown,
       tan, gray, dark green and the like. Bright
       colors that are intended to draw attention to a
       person’s footwear are not acceptable.
       Footwear with a closed toe is required. Flip
       flops, open-toed sandals and other similar
       shoes are not permitted. Closed-toe Crocs are
       acceptable provided they conform with the
       colors described above. GOLF SPIKES are
       prohibited.
10                     HICKS V. PGA TOUR

         4. Caddies’ clothing must conform to the
         Player Endorsement Policy as stated in the
         PGA TOUR Player Handbook and
         Tournament Regulations.1

    The Player Endorsement Policy (“Endorsement Policy”)
referenced in Regulation Four prohibits endorsing specific
categories of products, places limitations on the size and
location of endorsements, and specifies that “[a]ll
sponsorships, endorsements and promotional activities by
members, whether during or outside PGA TOUR
competitions, are subject to the approval of the PGA
TOUR.”2

    The Tour and Local Hosts have threatened to prevent
caddies who refuse to wear the bibs from participating in
tournaments. They have also directly contacted golfers to
determine whether the golfers would decline to hire caddies
who refused to wear the bibs. These tactics, combined with
the Tour’s requirement that each golfer have a caddy to
participate in a tournament, maximize the value of bib
advertising during tournament play.

    The Caddies contend that the Tour and Local Hosts
cannot compel them to wear the bibs. Relatedly, they allege
that by requiring the Caddies to wear the bibs, the Tour and

     1
     The excerpted text comes from the version of the Form used for the
2014–2015 Tour season. The Tour added Regulation Four concerning the
Player Endorsement Policy during the 2012 Tour season. Otherwise, the
Tour has made no relevant changes to the excerpted text since 2010.
     2
      The Caddies do not dispute the authenticity of the Form or
Endorsement Policy, which are referenced in the operative complaint and
were submitted to the district court by the Tour.
                        HICKS V. PGA TOUR                              11

Local Hosts have inhibited their endorsement rights under the
Endorsement Policy.3 Based on these allegations, the
Caddies assert contract, equitable quasi-contract, economic
duress, publicity, and unfair competition claims under
California law.4 See, e.g., Cal. Civ. Code § 3344(a)
(discussing publicity claims); Cal. Bus. & Prof. Code § 17200
(defining “unfair competition”). They also allege a false
endorsement claim under the Lanham Act. 15 U.S.C. § 1125.
Finally, the Caddies assert antitrust claims under Sections 1
and 2 of the Sherman Act. 15 U.S.C. §§ 1, 2.

    For their antitrust claims, the Caddies allege two relevant
product markets: the Endorsement Market and the Live
Action Advertising Market. They define the Endorsement
Market as “the national market for the endorsement of
products and services by participants in professional golf
tournaments.” Without the Tour’s requirement that the
Caddies wear bibs, the Caddies and golfers would be the only
sellers in this market. Indeed, the Caddies and golfers are the
only visible and recognizable individuals who participate in
golf tournaments.

    According to the Caddies, the Tour’s audience is a
distinct advertising market given its unique demographic.
The majority of Tour fans are older, Caucasian, travel via
airplane for business, and are interested in products such as
financial planning and vacation traveling.             These



    3
      The Caddies’ operative complaint names the Tour as the only
defendant.
    4
      The parties agree that California law applies to all of the state law
claims.
12                   HICKS V. PGA TOUR

characteristics allegedly distinguish the average Tour fan
from the average fan of other major sports.

    Moreover, endorsements from the Caddies and golfers
during tournament play are purportedly more effective than
other forms of golf-related advertising. A golf fan can ignore
other forms of advertising by flipping the page of a magazine,
clicking away from an online advertisement, or fast-
forwarding through television commercials with a DVR. In
contrast, a golf fan cannot ignore an in-action endorsement
from a caddy or golfer. The Caddies contend that this
enhanced effectiveness, combined with a unique degree of
price-flexibility provided by the possibility of hiring golfers
and caddies of varying skill levels, establishes the plausibility
of the Endorsement Market.

    The Caddies define the slightly more expansive Live
Action Advertising Market as “the national . . . market for in-
play or in-action commercial advertising at professional golf
events between commercial breaks.” In addition to
endorsements from the Caddies and golfers, this market
includes advertising space on and around the golf course that
live tournament, television broadcast, and webcast audiences
can see during in-play tournament action. The Tour and
Local Hosts provide the advertising space on and around the
course. The Caddies contend that the Live Action
Advertising Market constitutes a plausible product market for
similar reasons as above.

   The Caddies allege three antitrust claims reliant on these
proposed product markets. First, they contend that the Tour
and Local Hosts violate Section 1 of the Sherman Act by
agreeing to require the Caddies to wear the bibs, which
unreasonably restrains trade by reducing the product supply
                    HICKS V. PGA TOUR                      13

in the relevant markets. Second, the Caddies allege that the
Tour violates Section 2 of the Sherman Act by monopolizing
or attempting to monopolize the relevant markets through the
use of coercive and threatening conduct. Finally, the Caddies
allege that the Tour also violates Section 2 by engaging in
coercive reciprocal dealing—a variant of tying. Specifically,
the Caddies contend that the Tour leverages monopoly power
in the market for professional golf tournaments by selling the
right to participate in golf tournaments to the Caddies on the
condition that the Caddies sell their endorsement services to
the Tour.

    In February 2015, the Caddies first raised these claims
and sought class certification in district court. The Caddies
amended their complaint as of right in response to a motion
to change venue and amended again with the Tour’s consent.
The Tour then filed a motion to dismiss the Caddies’ Second
Amended Complaint. It argued that the Caddies failed to
plead any plausible claims for relief because the Caddies
consented to wearing the bibs and the proposed antitrust
product markets were implausible. The district court agreed.

     The district court concluded that Regulation Two in the
Form was unambiguous and authorized the Tour to require
the Caddies to wear bibs. It focused specifically on the
italicized language below:

       2.    Caddies shall wear uniforms and
       identification badges as prescribed by the host
       tournaments and PGA Tour. All caddies are
       required to wear solid-colored, Khaki-style
       long pants, which touch the top of the shoe, or
       solid-colored, knee-length, tailored shorts or
       skorts and a collared shirt while on club
14                  HICKS V. PGA TOUR

       property. T-shirts, jeans, culottes, skirts,
       capris, cut-off shorts and cargo-style shorts
       are not permitted. Acceptable colors shall be
       determined at the discretion of the
       Tournament Director.

     The district court recognized that “[i]n isolation” the
italicized “language might appear ambiguous.” The court
elaborated:

       On the one hand, a person might understand
       the first sentence of the paragraph to mean
       that caddies must wear whatever ‘uniforms’
       the host tournament and the Tour decide to
       ‘prescribe,’ without limitation . . . . On the
       other hand, one might understand the second
       sentence of the paragraph to be modifying the
       first one, so that the kinds of ‘uniforms’ a host
       tournament and Tour may ‘prescribe’ include
       the type and color of the pants and shirts
       caddies may wear, and nothing more.

It noted that the former interpretation authorizes the Tour to
require the Caddies to wear bibs, but the latter does not.

    However, the district court determined that in the “context
of this case,” the contractual provision was unambiguous. It
relied on the Caddies’ concession in their supplemental brief
opposing the Tour’s motion to dismiss that “the PGA Tour
has required caddies to wear bibs for decades.” This
“context,” along with the operative complaint’s allegation
that the Caddies “are forced to wear identical bibs during a
given tournament,” confirmed that the contractual provision
has a single reasonable interpretation: “[T]he caddies agreed
                     HICKS V. PGA TOUR                       15

the Tour could make them wear bibs.” In light of this
conclusion, and the fact that the operative complaint
confirmed that the Tour had not relinquished this contractual
right, the district court dismissed the breach of contract claim
with prejudice.

    The district court’s conclusion that the Caddies’ had
consented to wear the bibs led it to dismiss with prejudice the
unjust enrichment, publicity, and Lanham Act false
endorsement claims as well because each claim required a
lack of consent. The Caddies’ claim that they signed the
Form under economic duress was similarly dismissed with
prejudice because the Caddies “embark[ed] upon a profession
whose practitioners have long been required to wear bibs.”

    The district court also dismissed with prejudice the
Caddies’ antitrust claims for failure to plead a plausible
product market.        It assumed when considering the
Endorsement Market and the Live Action Advertising Market
that professional golf fans constituted a unique market for
certain advertisers. Even so, the court reasoned that while the
various forms of advertisements aimed at this demographic
have their differences, the Caddies failed to allege facts “from
which one could plausibly conclude that these different
methods of advertising to golf fans are not reasonably
interchangeable.” For example, “[i]f it became too expensive
to put a logo on a bridge” or a bib, “there is no logical reason
a company wouldn’t decide instead to put its logo on a
magazine ad, or on a wall in golf course clubhouses, or any
number of other places.” It concluded that the proposed
markets were “artificial [and] contorted to meet [the
Caddies’] litigation needs.”
16                  HICKS V. PGA TOUR

    Finally, the district court dismissed the Caddies’
remaining California unfair competition claim with prejudice
given its resolution of other related claims. The Caddies
timely appealed the district court’s dismissal of all claims.

    We review de novo the district court’s dismissal of the
Caddies’ complaint under Rule 12(b)(6) for “failure to state
a claim upon which relief can be granted.” Vega v. United
States, 881 F.3d 1146, 1152 (9th Cir. 2018). “To survive a
motion to dismiss, a complaint must contain sufficient factual
matter, accepted as true, to ‘state a claim to relief that is
plausible on its face.’” Ashcroft v. Iqbal, 556 U.S. 662, 678
(2009) (quoting Bell Atl. Corp. v. Twombly, 550 U.S. 544,
570 (2007)). “A claim has facial plausibility when the
plaintiff pleads factual content that allows the court to draw
the reasonable inference that the defendant is liable for the
misconduct alleged.” Id. (citing Twombly, 550 U.S. at 556).
Applying this standard is a “context-specific task” that
requires drawing on “judicial experience and common sense.”
Id. at 679.

                              II

   The district court properly concluded that the Caddies had
consented to wearing the bibs and that they did not do so
under economic duress.

                              A

   As an initial matter, the district court was not required to
convert the Tour’s Rule 12(b)(6) motion to a summary
judgment motion, as the Caddies allege, because it did not
consider any material outside the pleadings.
                    HICKS V. PGA TOUR                      17

    When ruling on a Rule 12(b)(6) motion, if “matters
outside the pleadings are presented to and not excluded by the
court, the motion must be treated as one for summary
judgment under Rule 56. All parties must be given a
reasonable opportunity to present all the material that is
pertinent to the motion.” Fed. R. Civ. P. 12(d).

    The “pleadings” include more than just the complaint.
We can consider “exhibits attached to the Complaint or
matters properly subject to judicial notice.” Daniels-Hall v.
Nat’l Educ. Ass’n, 629 F.3d 992, 998 (9th Cir. 2010).
Moreover, “[w]e may also consider documents whose
contents are alleged in a complaint and whose authenticity no
party questions, but which are not physically attached to the
[plaintiff’s] pleading.” Northstar Fin. Advisors Inc. v.
Schwab Invs., 779 F.3d 1036, 1043 (9th Cir. 2015) (brackets
in original) (internal quotations and citation omitted).
“[T]hose ‘facts’ [in a plaintiff’s complaint] which have since
been conclusively contradicted by plaintiffs’ concessions” are
also appropriate for consideration. Chongris v. Bd. of
Appeals of Town of Andover, 811 F.2d 36, 37 (1st Cir. 1987);
see also, e.g., McCorkle v. Bank of Am. Corp., 688 F.3d 164,
170, 172 (4th Cir. 2012) (affirming the district court’s
dismissal of a claim based on a “concession made at oral
argument [before the district court] by counsel for
Plaintiffs”).

   Here, the district court did not consider any matters
requiring conversion under Rule 12(d). The Caddies’
concession in their motion to dismiss briefing that “the PGA
Tour has required caddies to wear bibs for decades” was
appropriate to consider when ruling on the Rule 12(b)(6)
motion. See, e.g., Chongris, 811 F.2d at 37; McCorkle,
688 F.3d at 170, 172. In relying on this concession, the
18                   HICKS V. PGA TOUR

district court did not “pull[ ] a single statement out of [the
Caddies’] argument and interpret[ ] it as vitiating all the
factual allegations made in [their] complaint.” Campanelli v.
Bockrath, 100 F.3d 1476, 1481 (9th Cir. 1996). Instead, this
concession is entirely consistent with the allegations in the
operative complaint that the Tour has “nett[ed] millions of
dollars each year from bib advertising,” that the Caddies
“could have collectively earned over $50 million during the
2013–2014 golf season and similar sums during other
seasons at issue in this lawsuit,” and that the Tour has
“justif[ied] the practice because ‘that is the way it has been.’”
The Caddies fail to direct us to any factual allegations
inconsistent with its concession.

    The district court’s request for, and the parties’ joint
submission of, “judicially noticeable facts . . . about when the
PGA Tour started requiring caddies to wear bibs during
tournaments” and when the tournaments began having
“sponsored” names also did not result in consideration of
materials outside the pleadings. The Caddies admit that “the
district court did not directly cite th[is] evidence.” We need
not consider whether the materials in these submissions were
judicially noticeable at the pleading stage because the district
court “excluded” the materials by failing to rely on them
when ruling on the motion to dismiss. Fed. R. Civ. P. 12(d).

                               B

   The district court properly concluded that the Caddies had
consented to wear the bibs. The text of the Form, considered
with the Caddies’ concession that “the PGA Tour has
required [them] to wear bibs for decades,” confirms the
Caddies’ unambiguous consent to wearing bibs.
                     HICKS V. PGA TOUR                        19

    “Whether language in a contract is ambiguous is a
question of law.” Daniel v. Ford Motor Co., 806 F.3d 1217,
1224 (9th Cir. 2015) (quoting Producers Dairy Delivery Co.
v. Sentry Ins. Co., 718 P.2d 920, 925 (Cal. 1986)). If a
contract is ambiguous, it presents a question of fact
inappropriate for resolution on a motion to dismiss.
ASARCO, LLC v. Union Pac. R.R. Co., 765 F.3d 999,
1008–09 (9th Cir. 2014).

    We attempt to “ascertain [the parties’] intention solely
from the written contract, if possible.” Starlight Ridge S.
Homeowners Ass’n v. Hunter-Bloor, 99 Cal. Rptr. 3d 20, 25
(Ct. App. 2009). We begin by assuming contract terms
have their “plain, ordinary, popular or legal meaning.”
Hayter Trucking, Inc. v. Shell W. E&P, Inc., 22 Cal. Rptr. 2d
229, 238 (Ct. App. 1993). If the “ordinary and popular
sense” leaves doubt regarding a word’s meaning, we
“consider the circumstances under which the contract was
made[,] the matter to which it relates[,] . . . [and any] special
meaning [ ] given to [words] by usage.” Starlight Ridge, 99
Cal. Rptr. 3d at 25.

    The parties’ “prior course of dealings” is relevant in this
regard. Marin Storage & Trucking, Inc. v. Benco Contracting
& Eng’g, Inc., 107 Cal. Rptr. 2d 645, 652 (Ct. App. 2001).
Considering the parties’ course of dealing advances
California law’s “fundamental goal of contract
interpretation,” namely “to give effect to the mutual intent of
the parties as it existed at the time of contracting.” Skilstaf,
Inc. v. CVS Caremark Corp., 669 F.3d 1005, 1014–15 (9th
Cir. 2012) (internal alterations and citation omitted); see also
Kashmiri v. Regents of Univ. of Cal., 67 Cal. Rptr. 3d 635,
660 (Ct. App. 2007) (noting that contract law aims to “protect
the reasonable expectations of the parties” (quoting Ben-Zvi
20                  HICKS V. PGA TOUR

v. Edmar Co., 47 Cal. Rptr. 2d 12, 15 (Ct. App. 1995))).
After all, a term is not ambiguous “because of
‘[d]isagreement concerning the meaning of a phrase,’ or ‘the
fact that a word or phrase isolated from its context is
susceptible of more than one meaning.’” State v. Cont’l Ins.
Co., 281 P.3d 1000, 1004 (Cal. 2012) (quoting Castro v.
Fireman’s Fund Am. Life Ins. Co., 253 Cal. Rptr. 833, 836
(Ct. App. 1988)); id. at 1004–05 (A contract “cannot be found
to be ambiguous in the abstract.” (quoting Bank of the West
v. Superior Court, 833 P.2d 545, 552 (Cal. 1992))).

    With these principles in mind, the district court correctly
concluded that Regulation Two provides unambiguous
authorization for the Tour to require that the Caddies wear
bibs. Regulation Two states that “[c]addies shall wear
uniforms and identification badges as prescribed by the host
tournament and PGA Tour.” Both ordinary usage and the
parties’ course of dealing confirm that the Tour’s ability to
“prescribe[ ] . . . uniforms . . . [that] [c]addies shall wear”
authorizes the bib requirement.

    A uniform is commonly understood as a “dress of a
distinctive design or fashion worn by members of a particular
group and serving as a means of identification.” Merriam-
Webster’s Collegiate Dictionary 1292 (10th ed.1996). The
identical bibs that the Tour requires fall within this common
definition because individuals watching Tour tournaments are
able to identify the Caddies by the bibs they wear. Indeed, a
caddy simply wearing khaki pants and a collared blue polo
shirt would satisfy the Tour’s leg wear and shirt requirement,
but the individual would be indistinguishable from many golf
fans on the course. Placing a bib on the same caddy “serv[es]
as a means of identif[ying]” the individual as a caddy, rather
than a golf spectator. Id.
                        HICKS V. PGA TOUR                              21

    The Caddies’ concession that “the PGA Tour has required
caddies to wear bibs for decades” further confirms that the
bibs fall within Regulation Two’s use of the word
“uniforms.” In the context of the parties’ course of dealing,
a reasonable caddy signing the Form would reach a single
conclusion: Regulation Two’s reference to “uniforms”
included the bibs that the Tour “prescribed.”5

                                    C

   The district court also did not err in concluding that the
Caddies failed to allege plausibly that the Tour secured their
consent through economic duress.

    Economic duress can excuse an innocent party’s
contractual obligations when the other contracting party does
“a wrongful act which is sufficiently coercive to cause a
reasonably prudent person faced with no reasonable
alternative to succumb to the perpetrator’s pressure.” Rich &
Whillock, Inc. v. Ashton Dev., Inc., 204 Cal. Rptr. 86, 89 (Ct.
App. 1984). The doctrine only applies when the party
seeking relief “had no ‘reasonable alternative’ to the action it
now seeks to avoid (generally, agreeing to contract).”
CrossTalk Prods., Inc. v. Jacobson, 76 Cal. Rptr. 2d 615, 623
(Ct. App. 1998). No reasonable alternative may exist “when
the only other alternative is bankruptcy or financial ruin.”
Rich & Whillock, 204 Cal. Rptr. at 89. “If a reasonable

    5
       The Caddies’ contention that the Player Endorsement Policy alters
this conclusion is also incorrect. The Form notes that “[c]addies’ clothing
must conform to the Player Endorsement Policy.” However, under the
Player Endorsement Policy all “endorsements . . . are subject to approval
by the PGA Tour.” The Player Endorsement Policy—a policy referenced
in the Form—would not allow endorsements to the extent they conflict
with the Form’s requirement that the Caddies wear bibs.
22                      HICKS V. PGA TOUR

alternative was available, and there hence was no compelling
necessity to submit to the coercive demands, economic duress
cannot be established.” CrossTalk Prods., 76 Cal. Rptr. 2d at
623.

    The Caddies failed to allege a “wrongful act which [was]
sufficiently coercive” or that they faced “no reasonable
alternative [but] to succumb to the perpetrator’s pressure.”
Rich & Whillock, 204 Cal. Rptr. at 89. As the district court
noted, the Caddies “embark[ed] upon a profession whose
practitioners have long been required to wear bibs, and who
therefore have not been able to display logos on the part of
the shirt covered by the bib.” In these circumstances, “the
caddies[’] allegation that they were coerced into this
arrangement on threat of extreme economic hardship is not
plausible.”

                                    D

   In sum, the Caddies failed to state claims for breach of
contract and quasi-contract relief because they consented to
wearing the bibs.6 The Caddies also fail to state California


     6
       The Caddies’ quasi-contract claims include unjust enrichment,
quantum meruit, and money had and received. The Caddies’ consent to
wearing the bibs in exchange for participation in the tournaments defeats
these claims. See, e.g., Durell v. Sharp Healthcare, 108 Cal. Rptr. 3d 682,
699 (Ct. App. 2010) (“[A]n unjust enrichment claim does not lie where the
parties have an enforceable express contract.”); Newport Harbor Ventures,
LLC v. Morris Cerullo World Evangelism, 212 Cal. Rptr. 3d 216, 228 (Ct.
App. 2016) (“Quantum meruit recovery that is contrary to an express
contractual term is not allowed.”); Rutherford Holdings, LLC v. Plaza Del
Rey, 166 Cal. Rptr. 3d 864, 871 (Ct. App. 2014) (“In an action on an
express contract, a claim for money had and received is permitted where
there has been a total failure of consideration.”).
                     HICKS V. PGA TOUR                        23

state law publicity claims or a Lanham Act false endorsement
claim because they consented to wearing the bibs and
assigned to the Tour their “individual television, radio,
motion picture, photographic, electronic, . . . and all other
similar or related media rights with respect to [their]
participation in the Tournament[s].” Newcombe v. Adolf
Coors Co., 157 F.3d 686, 691–92 (9th Cir. 1998) (noting that
publicity claims under both California common law and
California Civil Code § 3344 require lack of consent); Abdul-
Jabbar v. Gen. Motors Corp., 85 F.3d 407, 410 (9th Cir.
1996) (indicating that a Lanham Act false endorsement claim
requires the “unauthorized” use of someone’s identity).
Finally, as discussed above, the Caddies fail to excuse their
consent by pleading a plausible economic duress claim.

                               III

    The district court also properly determined that the
Caddies had not alleged plausible product markets to support
their antitrust claims.

                               A

    Plaintiffs must plead a relevant market to state an antitrust
claim under the Sherman Act, unless they assert a per se
claim. Newcal Indus., Inc. v. Ikon Office Sol., 513 F.3d 1038,
1044–45 (9th Cir. 2008). While plaintiffs need not plead a
relevant market with specificity, “[t]here are . . . some legal
principles that govern the definition of an antitrust ‘relevant
market,’ and a complaint may be dismissed under Rule
12(b)(6) if the complaint’s ‘relevant market’ definition is
facially unsustainable.” Id. at 1045.
24                  HICKS V. PGA TOUR

    The relevant market must include both a geographic
market and a product market. Big Bear Lodging Ass’n v.
Snow Summit, Inc., 182 F.3d 1096, 1104 (9th Cir. 1999). The
latter, which is relevant to the present appeal, “must
encompass the product at issue as well as all economic
substitutes for the product.” Newcal Indus., 513 F.3d at 1045.
Economic substitutes have a “reasonable interchangeability
of use” or sufficient “cross-elasticity of demand” with the
relevant product. Id. (quoting Brown Shoe v. United States,
370 U.S. 294, 325 (1962)). Including economic substitutes
ensures that the relevant product market encompasses “the
group or groups of sellers or producers who have actual or
potential ability to deprive each other of significant levels of
business.” Id. (quoting Thurman Indus., Inc. v. Pay ‘N Pak
Stores, Inc., 875 F.2d 1369, 1374 (9th Cir. 1989)).

    Within a general product market, “well-defined
submarkets may exist which, in themselves, constitute
product markets for antitrust purposes.” Brown Shoe,
370 U.S. at 325. To plead an antitrust claim based on a
submarket, “the plaintiff must be able to show (but need not
necessarily establish in the complaint) that the alleged
submarket is economically distinct from the general product
market.” Newcal Indus., 513 F.3d at 1045. “In Brown Shoe,
the Supreme Court listed several ‘practical indicia’ of an
economically distinct submarket: ‘industry or public
recognition of the submarket as a separate economic entity,
the product’s peculiar characteristics and uses, unique
production facilities, distinct customers, distinct prices,
sensitivity to price changes, and specialized vendors.’” Id.
(quoting 370 U.S. at 325).
                        HICKS V. PGA TOUR                              25

                                    B

     Applying these principles here, the district court properly
concluded that the Caddies had failed to plead any plausible
product markets.7 The plausibility of the Caddies’ proposed
markets depends on two assumptions: (1) that advertisements
to golf fans constitute a unique product market and (2) that
“in-play” or “in-action” advertising during professional golf
tournaments (i.e., between commercial breaks)—either in any
format or endorsements alone—constitutes a unique
submarket. Even if we accept the former assumption,
“judicial experience and common sense” require rejecting the
latter. Iqbal, 556 U.S. at 679. As the district court noted,
the Caddies’ proposed submarkets8 are “not natural,”
“artificial,” and “contorted to meet their litigation needs.”



    7
      The Caddies conclusorily allege that at least some of the Tour’s
conduct constitutes a per se antitrust violation, which would excuse the
requirement to plead a relevant product market. Big Bear Lodging,
182 F.3d at 1104. However, they do not challenge on appeal the district
court’s failure to consider their claims under the per se framework. We
also are unpersuaded that the Caddies’ antitrust claims, as currently
pleaded, reveal the type of conduct “that courts’ ‘considerable experience’
has revealed to have ‘manifestly anti-competitive effects,’ and no
‘redeeming virtue,’ such that judges can ‘predict with confidence that it
would be invalidated in all or almost all instances under the rule of
reason.’” Cal. ex rel. Harris v. Safeway, Inc., 651 F.3d 1118, 1147 (9th
Cir. 2011) (quoting Leegin Creative Leather Prods., Inc. v. PSKS, Inc.,
551 U.S. 877, 886–87 (2007)).
    8
       The Caddies’ proposed markets are actually sub-submarkets.
Advertising to golf fans is a submarket of the general advertising market.
Advertising during live golf tournaments, whether through endorsements
alone or all means, is a further submarket of the submarket of advertising
to golf fans.
26                  HICKS V. PGA TOUR

    The Caddies’ submarkets—the Endorsement Market and
the Live Action Advertising Market—omit many economic
substitutes. Companies aiming to target professional golf
fans can do so by airing commercials during golf-related
television programs, radio broadcasts, or podcasts. They can
advertise on golf-related websites or social media pages.
They can also directly target golf fans by advertising through
a search engine or social media platform that provides
advertisers insights on users’ online history. As the district
court noted, “[i]f it became too expensive to put a logo on a
bridge” during a golf tournament, “there is no logical reason
a company wouldn’t decide instead to put its logo on a
magazine ad, or on a wall in golf course clubhouses, or any
number of other places.”

    The Caddies offer four arguments to contest this
conclusion. First, they note that advertising during the live-
action of golf tournaments cannot be avoided by “flipping the
page, clicking out of an ad, . . . fast[ ] forwarding with [a]
DVR,” or leaving the room during a commercial break.
Second, they claim that “endorsements made by the endorser
during competition provides a unique, exponentially more
effective opportunity to improve brand recognition and
validity when compared to endorsements made in print or in
television commercials.” Third, they contend that advertising
during live golf tournament action provides an element of
price flexibility because “the vast majority of companies
purchasing live action advertisements are smaller companies
who cannot or do not want to pay for advertising via
television commercials.”          Finally, they claim that
“econometric studies . . . will demonstrate that purchasers in
the [proposed markets] will not switch to products outside of
th[ose] market[s] in response to a small but significant and
non-transitory price increase by [the Tour] . . . to such a
                    HICKS V. PGA TOUR                        27

degree that the price increase is unprofitable.” None of these
arguments withstand modest scrutiny.

    The fact that golf fans can avoid some forms of
advertising fails to indicate that these advertising formats are
not “reasonabl[y] interchangeab[le]” with the products in the
proposed markets. Newcal Indus., 513 F.3d at 1045. The
Caddies’ alternative conclusion rests on the implausible
assumption that a distinct group of golf fans watches
tournament broadcasts but either consumes no other forms of
golf media or is uninfluenced by advertisements in all other
forms of golf media. The vast majority of golf fans who
watch tournament broadcasts certainly consume other forms
of golf media. Although these fans likely avoid some
advertisements in other golf media, the assumption that they
are not influenced by one or more of the diverse forms of
advertisements discussed above is implausible. Moreover,
even if a distinct group of golf fans exists that is only
influenced by live action advertising, for whatever reason, the
Caddies provide no explanation why this group of fans is
distinct for advertising purposes from the typical group of
golf fans.

    The Caddies’ claims of increased effectiveness and price
flexibility also fail to support their proposed markets. The
price of endorsement advertising during golf tournaments
would reflect any increased effectiveness compared to other
forms of advertising. This increased effectiveness would not
place the advertising format in a distinct market because, as
discussed above, companies can reach golf consumers
through other formats. The price flexibility in the proposed
markets also fails to demonstrate their plausibility. Although
small companies can advertise in the proposed markets by
hiring a lone little-known player or caddy, these same
28                  HICKS V. PGA TOUR

companies could advertise through smaller golf periodicals,
less frequented websites, and radio programs.

    Finally, the Caddies’ last claim is a legal conclusion
veiled as a factual allegation that we do not consider when
ruling on a motion to dismiss. Navajo Nation v. Dep’t of the
Interior, 876 F.3d 1144, 1163 (9th Cir. 2017) (“We do not . . .
assume the truth of legal conclusions merely because they are
cast in the form of factual allegations . . . .” (citation
omitted)). The Caddies merely restate a test for market
definition without any factual elaboration.            Theme
Promotions, Inc. v. News Am. Mktg. FSI, 546 F.3d 991, 1002
(9th Cir. 2008) (noting that one method of determining
whether a proposed market is viable is assessing “whether a
monopolist in the proposed market could profitably impose
a small but significant and nontransitory price increase”).

    In sum, the district court properly concluded that the
Caddies’ proposed product markets are “facially
unsustainable” because they fail to include many
“reasonabl[y] interchangeab[le]” products. Newcal Indus.,
513 F.3d at 1045.

                              C

    Our conclusion is consistent with the opinions of our
sister circuits. In Chapman v. New York State Division for
Youth, 546 F.3d 230, 237–38 (2d Cir. 2008), the Second
Circuit affirmed the dismissal of antitrust claims because the
plaintiffs’ proposed product market of “restraint training
services to private child care providers” did not “encompass
all interchangeable substitute products.” The plaintiffs
“failed to show how the market for restraint training services
to child care providers is any different from the larger market
                     HICKS V. PGA TOUR                          29

for restraint training services to other businesses, agencies,
and organizations.” Id. at 238 (emphasis in original). Even
after granting all factual inferences in the plaintiffs’ favor, the
court affirmed the dismissal of the claims because “[t]he
unifying characteristic of th[e] market is that each purchaser
needs to restrain individuals, not just children.” Id.
(emphasis added).

    Similarly, in PSKS, Inc. v. Leegin Creative Leather
Products, Inc., 615 F.3d 412, 417–19 (5th Cir. 2010), the
Fifth Circuit affirmed the dismissal of the plaintiff’s claim
that vertical resale price maintenance agreements violated the
Sherman Act because neither of the two proposed product
markets “encompasse[d] interchangeable substitute products
or recognize[d] the cross-elasticity of demand.” The first
proposed market—limited to a specific brand of women’s
accessories—was implausible because there was “no
structural barrier to the interchangeability of [the specific
brand of] products with goods produced by competing
manufacturers.” Id. at 418. The second proposed market for
“brand-name women’s accessories” was also implausible
because the plaintiff failed to allege why name brand goods
“are not interchangeable with non-brand name” women’s
accessories. Id. at 416, 418.

    Moreover, many courts have rejected antitrust claims
reliant on proposed advertising markets limited to a single
form of advertising. See, e.g., Am. Online, Inc. v.
GreatDeals.Net, 49 F. Supp. 2d 851, 858 (E.D. Va. 1999)
(dismissing the plaintiff’s monopolization claim in part
because it attempted to “restrict the market to e-mail
advertising [even though] [t]here are numerous substitutes for
e-mail advertising, some of which are less expensive,
including use of the World Wide Web, direct mail, billboards,
30                   HICKS V. PGA TOUR

television, newspapers, radio, and leaflets, to name a few”);
Huron Valley Publ’g Co. v. Booth Newspapers, Inc., 336 F.
Supp. 659, 662 (E.D. Mich. 1972) (denying the plaintiff’s
motion for a preliminary injunction on monopolization claims
in part because “the relevant market includes all modes of
retail advertising” and not just “newspaper advertising alone”
as the plaintiff argued); see also AD/SAT, Div. of Skylight,
Inc. v. Associated Press, 181 F.3d 216, 228–29 (2d Cir. 1999)
(affirming grant of summary judgment for the defendant in
part because “the market for rush electronic delivery of
advertisements to newspapers is not a viable one” because
“there is significant cross-elasticity of demand for rush and
non-rush delivery services”).

                               D

    In sum, the district court correctly dismissed the Caddies’
antitrust claims for failure to allege a relevant product market.
Newcal Indus., 513 F.3d at 1044; see also Freeman v. San
Diego Ass’n of Realtors, 322 F.3d 1133, 1146 n.14 (9th Cir.
2003) (“[D]istinct product markets are crucial to a tying
claim.”).

    This conclusion also confirms that the district court
properly dismissed the Caddies’ California unfair competition
claim that the Tour’s conduct was “unlawful, unfair or
fraudulent.” Cal. Bus. & Prof. Code § 17200. The Caddies
failed to plead that any of the Tour’s conduct was unlawful or
unfair. Berryman v. Merit Prop. Mgmt., Inc., 62 Cal. Rptr. 3d
177, 185 (Ct. App. 2007) (“[A] violation of another law is a
predicate for stating a cause of action under the [unfair
competition law’s] unlawful prong.”); Chavez v. Whirlpool
Corp., 113 Cal. Rptr. 2d 175, 184 (Ct. App. 2001) (“If the
same conduct is alleged to be both an antitrust violation and
                       HICKS V. PGA TOUR                            31

an ‘unfair’ business act or practice for the same reason . . . the
determination that the conduct is not an unreasonable
restraint of trade necessarily implies that the conduct is not
‘unfair’ towards consumers.”). Their allegations that the
Tour “misled bib sponsors into believing that Plaintiffs
voluntarily consented to wearing the bibs without
compensation” also fail under the fraud prong because the
Caddies did consent to wearing the bibs.

                                  E

    While we agree with the district court that the Caddies
failed to plead a plausible product market, we vacate the
dismissal with prejudice of the antitrust and California unfair
competition law claims.9 “Dismissal with prejudice and
without leave to amend is not appropriate unless it is clear on
de novo review that the complaint could not be saved by
amendment.” Eminence Capital, LLC v. Aspeon, Inc.,
316 F.3d 1048, 1052 (9th Cir. 2003). “A simple denial of
leave to amend without any explanation by the district court
is subject to reversal.” Id. “Such a judgment is ‘not an
exercise of discretion; it is merely abuse of that discretion and
inconsistent with the spirit of the Federal Rules.’” Id.
(quoting Foman v. Davis, 371 U.S. 178, 182 (1962)).

    The district court made a “simple denial of leave to
amend” here without adequate explanation. Id. It only noted
that the Caddies were not “able to explain how they could
state an antitrust claim using a plausible product market
definition.” This insufficient consideration of the factors


    9
       As discussed above, if the Caddies plead facts that support an
antitrust claim, these facts may also support a valid California unfair
competition claim.
32                   HICKS V. PGA TOUR

discussed in Foman constitutes an abuse of discretion
considering that the district court only dismissed the
complaint once, the Tour fails to identify any specific
prejudice it would experience, and we cannot conclude that
amendment would be futile. See, e.g., id. (“[P]rejudice to the
opposing party . . . carries the greatest weight” when deciding
whether to grant leave to amend.). Therefore, we remand this
issue for the district court to reconsider its decision to deny
the Caddies leave to amend the antitrust and unfair
competition claims.

                              IV

    In summary, because the Caddies consented to wearing
the bibs while not in a state of economic duress, the district
court properly dismissed with prejudice the contract, quasi-
contract, California publicity, Lanham Act false endorsement,
and economic duress claims. The district court properly
dismissed the antitrust claims for failure to state a relevant
market and the California unfair competition claims for
failure to plead that any of the Tour’s conduct was unlawful,
unfair, or fraudulent. However, we remand the case to the
district court to reconsider its decision to deny the Caddies
leave to amend their federal antitrust and California unfair
competition claims.

  AFFIRMED in part; VACATED in part; and
REMANDED.

     Each party to bear its own costs.
