FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

OLEAN WHOLESALE GROCERY

COOPERATIVE, INC., BEVERLY

YOUNGBLOOD, PACIFIC

GROSERVICE, INC., DBA Pitco

Foods, CAPITOL HILL

SUPERMARKET, LOUISE ANN DAVIS

MATTHEWS, JAMES WALNUM, COLIN

MOORE, JENNIFER A. NELSON,

ELIZABETH DAVIS-BERG, LAURA

CHILDS; NANCY STILLER; BONNIE

VANDERLAAN; KRISTIN MILLICAN;

TREPCO IMPORTS AND

DISTRIBUTION, LTD.; JINKYOUNG

MOON; COREY NORRIS; CLARISSA

SIMON; AMBER SARTORI; NIGEL

WARREN; AMY JOSEPH; MICHAEL

JUETTEN; CARLA LOWN; TRUYEN

TON-VUONG, AKA David Ton; A-1

DINER; DWAYNE KENNEDY; RICK

MUSGRAVE; DUTCH VILLAGE

RESTAURANT; LISA BURR; LARRY

DEMONACO; MICHAEL BUFF; ELLEN

PINTO; ROBBY REED; BLAIR HYSNI;

DENNIS YELVINGTON; KATHY

DURAND GORE; THOMAS E.

WILLOUGHBY III; ROBERT FRAGOSO;

SAMUEL SEIDENBURG; JANELLE

ALBARELLO; MICHAEL COFFEY;

JASON WILSON; JADE CANTERBURY;

No. 19-56514

D.C. No.

3:15-md-02670-

DMS-MDD

OPINION
2 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

NAY ALIDAD; GALYNA

ANDRUSYSHYN; ROBERT BENJAMIN;

BARBARA BUENNING; DANIELLE

GREENBERG; SHERYL HALEY; LISA

HALL; TYA HUGHES; MARISSA

JACOBUS; GABRIELLE KURDT; ERICA

PRUESS; SETH SALENGER; HAROLD

STAFFORD; CARL LESHER; SARAH

METIVIER SCHADT; GREG STEARNS;

KARREN FABIAN; MELISSA

BOWMAN; VIVEK DRAVID; JODY

COOPER; DANIELLE JOHNSON;

HERBERT H. KLIEGERMAN; BETH

MILLINER; LIZA MILLINER; JEFFREY

POTVIN; STEPHANIE GIPSON;

BARBARA LYBARGER; SCOTT A.

CALDWELL; RAMON RUIZ; THYME

CAFE & MARKET, INC.; HARVESTERS

ENTERPRISES, LLC; AFFILIATED

FOODS, INC.; PIGGLY WIGGLY

ALABAMA DISTRIBUTING CO., INC.;

ELIZABETH TWITCHELL; TINA

GRANT; JOHN TRENT; BRIAN LEVY;

LOUISE ADAMS; MARC BLUMSTEIN;

JESSICA BREITBACH; SALLY

CRNKOVICH; PAUL BERGER;

STERLING KING; EVELYN OLIVE;

BARBARA BLUMSTEIN; MARY

HUDSON; DIANA MEY; ASSOCIATED

GROCERS OF NEW ENGLAND, INC.;

NORTH CENTRAL DISTRIBUTORS,

LLC; CASHWA DISTRIBUTING CO. OF

KEARNEY, INC.; URM STORES, INC.;

WESTERN FAMILY FOODS, INC.;
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 3

ASSOCIATED FOOD STORES, INC.;

GIANT EAGLE, INC.; MCLANE

COMPANY, INC.; MEADOWBROOK

MEAT COMPANY, INC.; ASSOCIATED

GROCERS, INC.; BILO HOLDING,

LLC; WINNDIXIE STORES, INC.;

JANEY MACHIN; DEBRA L. DAMSKE;

KEN DUNLAP; BARBARA E. OLSON;

JOHN PEYCHAL; VIRGINIA RAKIPI;

ADAM BUEHRENS; CASEY

CHRISTENSEN; SCOTT DENNIS;

BRIAN DEPPERSCHMIDT; AMY E.

WATERMAN; CENTRAL GROCERS,

INC.; ASSOCIATED GROCERS OF

FLORIDA, INC.; BENJAMIN FOODS

LLC; ALBERTSONS COMPANIES

LLC; H.E. BUTT GROCERY

COMPANY; HYVEE, INC.; THE

KROGER CO.; LESGO PERSONAL

CHEF LLC; KATHY VANGEMERT;

EDY YEE; SUNDE DANIELS;

CHRISTOPHER TODD; PUBLIX SUPER

MARKETS, INC.; WAKEFERN FOOD

CORP.; ROBERT SKAFF; WEGMANS

FOOD MARKETS, INC.; JULIE WIESE;

MEIJER DISTRIBUTION, INC.; DANIEL

ZWIRLEIN; MEIJER, INC.; SUPERVALU

INC.; JOHN GROSS & COMPANY;

SUPER STORE INDUSTRIES; W LEE

FLOWERS & CO INC.; FAMILY

DOLLAR SERVICES, LLC; AMY

JACKSON; FAMILY DOLLAR STORES,

INC.; KATHERINE MCMAHON;

DOLLAR TREE DISTRIBUTION, INC.;
4 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

JONATHAN RIZZO; GREENBRIER

INTERNATIONAL, INC.; JOELYNA A.

SAN AGUSTIN; ALEX LEE, INC.;

REBECCA LEE SIMOENS; BIG Y

FOODS, INC.; DAVID TON; KVAT

FOOD STORES, INC., DBA Food City;

AFFILIATED FOODS MIDWEST

COOPERATIVE, INC.; MERCHANTS

DISTRIBUTORS, LLC; BROOKSHIRE

BROTHERS, INC.; SCHNUCK

MARKETS, INC.; BROOKSHIRE

GROCERY COMPANY; KMART

CORPORATION; CERTCO, INC.;

RUSHIN GOLD, LLC, DBA The Gold

Rush; UNIFIED GROCERS, INC.;

TARGET CORPORATION; SIMONHINDI, LLC; Fareway Stores, Inc.;

Moran Foods, LLC, DBA Save-ALot; WOODMAN’S FOOD MARKET,

INC.; DOLLAR GENERAL

CORPORATION; SAM’S EAST, INC.;

DOLGENCORP, LLC; SAM’S WEST,

INC.; KRASDALE FOODS, INC.;

WALMART STORES EAST, LLC; CVS

PHARMACY, INC.; WALMART STORES

EAST, LP; BASHAS’ INC.; WAL-MART

STORES TEXAS, LLC; MARC

GLASSMAN, INC.; WAL-MART

STORES, INC.; 99 CENTS ONLY

STORES; JESSICA BARTLING; AHOLD

U.S.A., INC.; GAY BIRNBAUM;

DELHAIZE AMERICA, LLC; SALLY

BREDBERG; ASSOCIATED

WHOLESALE GROCERS, INC.; KIM
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 5

CRAIG; MAQUOKETA CARE CENTER;

GLORIA EMERY; ERBERT &

GERBERT’S, INC.; ANA GABRIELA

FELIX GARCIA; JANET MACHEN;

JOHN FRICK; PAINTED PLATE

CATERING; KATHLEEN GARNER;

ROBERT ETTEN; ANDREW GORMAN;

GROUCHO’S DELI OF FIVE POINTS,

LLC; EDGARDO GUTIERREZ;

GROUCHO’S DELI OF RALEIGH;

ZENDA JOHNSTON; SANDEE’S

CATERING; STEVEN KRATKY;

CONFETTI’S ICE CREAM SHOPPE;

KATHY LINGNOFSKI; END PAYER

PLAINTIFFS; LAURA MONTOYA;

KIRSTEN PECK; JOHN PELS; VALERIE

PETERS; ELIZABETH PERRON; AUDRA

RICKMAN; ERICA C. RODRIGUEZ,

Plaintiffs-Appellees,

and

JESSICA DECKER, JOSEPH A.

LANGSTON, SANDRA POWERS,

GRAND SUPERCENTER, INC., THE

CHEROKEE NATION, US FOODS, INC.,

SYSCO CORPORATION, GLADYS,

LLC, SPARTANNASH COMPANY,

BRYAN ANTHONY REO,

Plaintiffs,

v.
6 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

BUMBLE BEE FOODS LLC; STARKIST

CO.; DONGWON INDUSTRIES CO.,

LTD.,

Defendants-Appellants,

and

KING OSCAR, INC.; THAI UNION

FROZEN PRODUCTS PCL; DEL

MONTE FOODS COMPANY; TRI

MARINE INTERNATIONAL, INC.;

DONGWON ENTERPRISES; DEL

MONTE CORP.; CHRISTOPHER D.

LISCHEWSKI; LION CAPITAL

(AMERICAS), INC.; BIG CATCH

CAYMAN LP, AKA Lion/Big Catch

Cayman LP; FRANCIS T

ENTERPRISES; GLOWFISCH

HOSPITALITY; THAI UNION NORTH

AMERICA, INC.,

Defendants.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 7

Appeal from the United States District Court

for the Southern District of California

Dana M. Sabraw, Chief District Judge, Presiding

Argued and Submitted En Banc September 22, 2021

Pasadena, California

Filed April 8, 2022

Before: Andrew J. Kleinfeld, Sidney R. Thomas, Susan P.

Graber, William A. Fletcher, Ronald M. Gould, Richard A.

Paez, Consuelo M. Callahan, Sandra S. Ikuta, Paul J.

Watford, Michelle T. Friedland and Kenneth K. Lee,

Circuit Judges.

Opinion by Judge Ikuta;

Dissent by Judge Lee
8 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

SUMMARY*

Antitrust / Class Certification

The en banc court filed an opinion affirming the district

court’s order certifying three subclasses of tuna purchasers

who alleged that the suppliers violated federal and state

antitrust laws. The en banc court held that the district court

did not abuse its discretion in concluding that the purchasers’

statistical regressionmodel, along with other expert evidence,

was capable of showing that a price-fixing conspiracy caused

class-wide antitrust impact, thus satisfying one of the

prerequisites for bringing a class action under Federal Rule of

Civil Procedure 23(b)(3).

To take advantage of Rule 23’s procedure for aggregating

claims, plaintiffs must make two showings. First, under

Rule 23(a), they must establish that “there are questions of

law or fact common to the class,” as well as demonstrate

numerosity, typicality, and adequacy of representation. 

Second, the plaintiffs must show that the class fits into one of

three categories under Rule 23(b). To qualify for the third

category, Rule 23(b)(3) the district court must find that

“questions of law or fact common to class members

predominate over any questions affecting only individual

members.”

Joining other circuits, the en banc court held that

plaintiffs must prove by a preponderance of the evidence the

facts necessary to carry the burden of establishing that the

* This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 9

prerequisites of Rule 23 are satisfied. The en banc court held

that to prove a common question of law or fact that relates to

a central issue in an antitrust class action, plaintiffs must

establish that essential elements of the cause of action, such

as the existence of an antitrust violation or antitrust impact,

are capable of being established through a common body of

evidence, applicable to the whole class.

The en banc court held that in making the determinations

necessary to find that the prerequisites of Rule 23(b)(3) are

satisfied, the district court may weigh conflicting expert

testimony and resolve expert disputes. In determining

whether the “common question” prerequisite is met, the

district court is limited to resolving whether the evidence

establishes that a common question is capable of class-wide

resolution, not whether the evidence in fact establishes that

plaintiffs would win at trial. The district court must also

resolve disputes about historical facts if necessary to

determine whether the plaintiffs’ evidence is capable of

resolving a common issue central to the plaintiffs’ claims. 

Therefore, the district court cannot decline certification

merely because it considers plaintiffs’ evidence relating to the

common question to be unpersuasive and unlikely to succeed

in carrying the plaintiffs’ burden of proof on that issue. Nor

can a district court decline to certify a class that will require

determination of some individualized questions at trial, so

long as such questions do not predominate over the common

questions.

The en banc court held that when individualized questions

relate to the injury status of class members, Rule 23(b)(3)

requires that the court determine whether individualized

inquiries about such matters would predominate over

common questions. Therefore, the en banc court rejected the
10 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

argument that Rule 23 does not permit the certification of a

class that potentially includes more than a de minimis number

of uninjured class members.

Beginning with the “DPP” class of direct purchasers of

the tuna suppliers’ products, such as nationwide retailers and

regional grocery stores, the panel held that in order to prevail

on their antitrust claim, the DPP class was required to prove

that the tuna suppliers engaged in a conspiracy (an antitrust

violation), which resulted in antitrust impact in the form of

higher prices paid by each member of the class, which in turn

led to measurable damages. The question whether each

member of the DPP class suffered antitrust impact was

central to the validity of each of the DPP claims. The central

questions on appeal were whether the expert evidence

presented by the DPPs was capable of resolving this issue “in

one stroke,” and whether this common question predominated

over any individualized inquiry.

The en banc court concluded that the district court did not

abuse its discretion in certifying the class. The DPPs relied

on the expert testimony and report of Dr. Russell Mangum,

whose findings about the tuna market and tuna suppliers’

collusive behavior, pricing correlation test, regression model,

and robustness checks confirmed his theory that the pricefixing conspiracy resulted in substantial price impacts, and

that the impact was common to the DPPs during the collusion

period. The en banc court concluded that the district court

did not make any legal or factual error when, in considering

whether the DPPs’ evidence was capable of establishing

antitrust impact for the class as a whole, the district court

reviewed Dr. Mangum’s expert testimony and report, the

rebuttal testimony and report by Dr. John Johnson, and

Dr. Mangum’s reply, and then addressed the parties’ disputes. 
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 11

The district court thus properly concluded that Dr. Mangum’s

pooled regression model, along with other evidence, was

capable of answering the question whether there was antitrust

impact due to the collusion on a class-wide basis, thus

satisfying this prerequisite of Rule 23(b)(3).

The en banc court held that the district court did not abuse

its discretion in determining that the evidence presented by

the DPPs proved: (1) that the element of antitrust impact was

capable of being established class-wide through common

proof, and (2) that this common question predominated over

individual questions. The en banc court rejected any

categorical argument that a pooled regression model cannot

control for variables relating to the individual differences

among class members. The en banc court also rejected the

argument that, in this case, the model’s output could not

plausibly serve as common evidence for all class members

given the individual differences among those class members. 

The en banc court held that the district court did not err by

failing to resolve a dispute between the parties as to whether

28 percent of the class did not suffer antitrust impact. Rather,

the district court fulfilled its obligation to resolve the disputes

raised by the parties in order to satisfy itself that the evidence

proves the prerequisites for Rule 23(b)(3), which was that the

evidence was capable of showing that the DPPs suffered

antitrust impact on a class-wide basis.

The en banc court held that the district court also did not

abuse its discretion in determining that the evidence

presented by the “CFP” class of indirect purchasers of bulksized tuna products and the “EPP” class of individual end

purchasers was capable of proving the element of antitrust

impact under California’s Cartwright Act, thus satisfying the

prerequisites of Rule 23(b)(3).
12 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Dissenting, Judge Lee, joined by Judge Kleinfeld, wrote

that the majority opinion allowed the district court to certify

a class, even though potentially about one out of three class

members suffered no injury. Judge Lee wrote that if

defendants’ econometrician expert was correct that almost a

third of the class members may not have suffered injury, then

plaintiffs did not show the predominance of common issues

under Rule 23(b). He wrote that because class action cases

almost always settle once a court certifies a class, a district

court must serve as a gatekeeper to resolve key issues

implicating Rule 23 requirements, including whether too

many putative class members suffered no injury, at the class

certification stage. Further, the majority’s rejection of a de

minimis rule, under which the number of uninjured class

members should be de minimis, created a circuit split.

COUNSEL

Gregory G. Garre (argued), Samir Deger-Sen, and Shannon

Grammel, Latham & Watkins LLP, Washington, D.C.;

Christopher S. Yates, Belinda S. Lee, and Ashley M. Bauer,

Latham & Watkins LLP, San Francisco, California; for

Defendants-Appellants StarKist Co. and Dongwon Industries

Co. Ltd.

Christopher L. Lebsock (argued), Michael P. Lehmann,

Bonny E. Sweeney, and Samantha J. Stein, Hausfeld LLP,

San Francisco, California, for Plaintiffs-Appellees Direct

Purchaser Plaintiff Class.

Jonathan W. Cuneo (argued), Joel Davidow, and Blaine

Finley, Cuneo Gilbert & Laduca LLP, Washington, D.C., for
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 13

Plaintiffs-Appellees Commercial Food Preparer Plaintiff

Class.

Thomas H. Burt (argued), Wolf Haldenstein Adler Freeman

& Herz LLP, New York, New York; Betsy C. Manifold,

Rachele R. Byrd, Marisa C. Livesay, and Brittany N. DeJong,

Wolf Haldenstein Adler Freeman & Herz LLP, San Diego,

California; for Plaintiffs-Appellees End Payer Plaintiff Class.

Corbin K. Barthold and Cory L. Andrews, Washington, D.C.,

for Amicus Curiae Washington Legal Foundation.

Ashley C. Parrish and Joshua N. Mitchell, King & Spalding

LLP, Washington, D.C.; Steven P. Lehotsky, Jonan D. Urick,

Daryl Joseffer, and Jennifer B. Dickey, United States

Chamber Litigation Center; Anne M. Voigts, Quyen L. Ta,

and Suzanne E. Nero, King & Spalding LLP, San Francisco,

California; Kerry Perigoe, King & Spalding LLP, Los

Angeles, California; Christopher A. Mohr, Software &

Information IndustryAssociation, Washington, D.C.; Jeanine

Poltronieri, Internet Association, Washington, D.C.; for

Amici Curiae Chamber of Commerce of the United States of

America, Software Information Industry Association, and

Internet Association.

Randy M. Stutz, American Antitrust Institute, Washington,

D.C.; Professor Joshua P. Davis, University of San Francisco

School of Law, San Francisco, California; Ellen Meriwether,

Cafferty Clobes Meriwether & Sprengal, Media,

Pennsylvania; for Amicus Curiae American Antitrust

Institute.
14 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Scott L. Nelson and Allison M. Zieve, Public Citizen

Litigation Group, Washington, D.C., for Amicus Curiae

Public Citizen Inc.

Jocelyn D. Larkin, Lindsay Nako, and David S. Nahmias,

Impact Fund, Berkeley, California, for Amici Curiae Impact

Fund, Bet Tzedek, California Rural Legal Assistance

Foundation, Centro Legal de la Raza, Legal Aid at Work, and

Public Counsel.

Karla Gilbride, Washington, D.C., as and for Amicus Curiae

Public Justice P.C.

Deborah A. Elman and Chad Holtzman, Garwin Gerstein &

Fisher LLP, New York, New York; Warren T. Burns and

Kyle K. Oxford, Burns Charest LLP, Dallas, Texas; Robert S.

Kitchenoff, President; Lin Y. Chan, Vice President,

Committee to Support the Antitrust Laws, Washington, D.C.;

for Amicus Curiae Committee to Support the Antitrust Laws.

Jonathan F. Cohn, Joshua J. Fougere, and Jacquelyn E.

Fradette, Sidley Austin LLP, Washington, D.C., for Amicus

Curiae Consumer Healthcare Products Association.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 15

OPINION

IKUTA, Circuit Judge:

The primary suppliers of packaged tuna in the United

States appeal the district court’s order certifying three classes

of tuna purchasers who allege the suppliers violated federal

and state antitrust laws. The main issue on appeal is whether

the purchasers’ statistical regression model, along with other

expert evidence, is capable of showing that a price-fixing

conspiracy caused class-wide antitrust impact, thus satisfying

one of the prerequisites for bringing a class action under Rule

23(b)(3) of the Federal Rules of Civil Procedure. Because the

district court did not abuse its discretion in concluding that

Rule 23(b)(3) was satisfied, we affirm.

I

Bumble Bee,1 StarKist, and Chicken of the Sea (COSI),

and their parent companies are the largest suppliers of

packaged tuna in the United States (referred to collectively as

the “Tuna Suppliers”). Their products include packaged tuna

sold to direct purchasers like Costco and Walmart, and foodservice-size tuna products sold to various distributors for

resale. Together, the Tuna Suppliers sell over 80 percent of

the packaged tuna in the country.

In late 2015, the United States Department of Justice

(DOJ) opened an investigation into the packaged tuna

1 As a result of Appellant Bumble Bee Foods LLC’s bankruptcy

proceeding, appellate proceedings against Bumble Bee Foods have been

held in abeyance due to the automatic stay imposed by 11 U.S.C. § 362.

Dkt. No. 51.
16 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

industry for violations of federal antitrust law. The DOJ

investigation uncovered evidence of a price-fixing scheme

among the Tuna Suppliers, which led the DOJ to enter

multiple indictments alleging a criminal conspiracy to fix

prices of canned tuna for the period from approximately

November 2011 through December 2013. Bumble Bee,

StarKist, and three tuna industry executives pleaded guilty to

the conspiracy. Bumble Bee’s former CEO was convicted by

a jury of a conspiracy to fix prices.2 COSI cooperated with

the DOJ and admitted to price fixing in exchange for

leniency.

A number of purchasers of the Tuna Suppliers’ products

(referred to collectively as the “Tuna Purchasers”) filed

putative class actions against the Tuna Suppliers alleging

violations of various federal and state antitrust laws. The

Tuna Purchasers alleged that the Tuna Suppliers engaged in

a conspiracy fromNovember 2010 through at least December

31, 2016 to fix prices of tuna, along with other collusive

activities in furtherance of the price-fixing conspiracy. The

Tuna Purchasers alleged that they were damaged by the

2 Plea Agreement, United States v. Bumble Bee Foods LLC, No.

3:17-cr-00249-EMC (N.D. Cal. Aug. 2, 2017), ECF No. 32; Plea

Agreement, United States v. Worsham, No. 3:16-cr-00535-EMC (N.D.

Cal. Mar. 15, 2017), ECF No. 14; Plea Agreement, United States v.

Cameron, No. 3:16-cr-00501-EMC (N.D. Cal. Jan. 25, 2017), ECF No.

18; Plea Agreement, United States v. Hodge, No. 3:17-cr-00297-EMC

(N.D. Cal. June 28, 2017), ECF No. 13; Plea Agreement, United States v.

StarKist Co., No. 3:18-cr-00513-EMC (N.D. Cal. Nov. 14, 2018),

ECF No. 24.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 17

conspiracy because they paid supra-competitive prices for the

Tuna Suppliers’ products.3

The Tuna Purchasers’ actions were consolidated in a

multidistrict litigation pretrial proceeding in the Southern

District of California. The Tuna Purchasers consist of three

putative subclasses: (i) direct purchasers of the Tuna

Suppliers’ products, such as nationwide retailers and regional

grocery stores, who purchased packaged tuna between June

1, 2011 and July 1, 2015 (the “DPPs”); (ii) indirect

purchasers of the Tuna Suppliers’ products who bought bulksized tuna products between June 2011 and December 2016

for prepared food or resale (the “CFPs”); and (iii) individual

end purchasers who bought the Tuna Suppliers’ products

between June 1, 2011 and July 1, 2015 for personal

consumption (the “EPPs”).

In 2018, the Tuna Purchasers moved to certify the three

subclasses under Rule 23 of the Federal Rules of Civil

Procedure to proceed as a class action. See Fed. R. Civ. P.

23(a), (b)(3). To demonstrate class-wide antitrust impact,

each subclass proffered evidence from a different economist,

each of whomemployed substantially similar methodologies,

to show that each member of the subclasses had paid an

overcharge caused by the Tuna Suppliers’ conspiracy. The

Tuna Suppliers contested this expert evidence through their

own economists. The district court held a three-day

evidentiary hearing on the certification motion, and heard

3 Supra-competitive prices are those prices elevated “above

competitive levels” by a market participant who “exercise[s] [its] market

power” to do so. ABA Section of Antitrust Law, Econometrics: Legal,

Practical, and Technical Issues 252 (2d ed. 2014) (“Econometrics”).
18 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

substantial testimony from each expert witness. In July 2019,

the district court certified all three subclasses.

The Tuna Suppliers timely appealed, and a panel of this

court vacated the district court’s order and remanded. See

Olean Wholesale Grocery Coop., Inc. v. Bumble Bee Foods

LLC, 993 F.3d 774, 794 (9th Cir. 2021), reh’g en banc

granted, 5 F.4th 950 (9th Cir. 2021). We took the case en

banc to consider whether the district court erred in finding

that each subclass satisfied the requirement that “questions of

law or fact common to class members predominate over any

questions affecting only individual members.” Fed. R. Civ.

P. 23(b)(3).

We have jurisdiction under 28 U.S.C. § 1292(e) and

Rule 23(f) of the Federal Rules of Civil Procedure. We

review the decision to certify a class and “any particular

underlying Rule 23 determination involving a discretionary

determination” for an abuse of discretion. Yokoyama v.

Midland Nat’l Life Ins. Co., 594 F.3d 1087, 1091 (9th Cir.

2010). We review the district court’s determination of

underlying legal questions de novo, id., and its determination

of underlying factual questions for clear error, see Ruiz

Torres v. Mercer Canyons Inc., 835 F.3d 1125, 1132 (9th Cir.

2016). The Supreme Court has indicated that a court’s

determination regarding what a statistical regression model

may prove or is capable of proving is not a question of fact,

even though there may be disputed issues of fact raised by

“the data contained within an econometric model.” Comcast

Corp. v. Behrend, 569 U.S. 27, 36 n.5 (2013). Accordingly,

we review the district court’s determination that a statistical

regression model, along with other expert evidence, is

capable of showing class-wide impact, thus satisfying one of

the prerequisites of Rule 23(b)(3) of the Federal Rules of
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 19

Civil Procedure, for an abuse of discretion. See Yokoyama,

594 F.3d at 1091.

II

A

Rule 23 provides a procedural mechanism for “a federal

court to adjudicate claims of multiple parties at once, instead

of in separate suits.” Shady Grove Orthopedic Assocs., P.A.

v. Allstate Ins. Co., 559 U.S. 393, 408 (2010). As a claimsaggregating device, Rule 23 “leaves the parties’ legal rights

and duties intact and the rules of decision unchanged,” id.,

and it does not affect the substance of the claims or plaintiffs’

burden of proof, see 28 U.S.C. § 2072(b).

To take advantage of Rule 23’s procedure for aggregating

claims, plaintiffs must make two showings. First, the

plaintiffs must establish “there are questions of law or fact

common to the class,” as well as demonstrate numerosity,

typicality and adequacy of representation.4 Fed. R. Civ. P.

4

 Rule 23(a) provides:

Prerequisites. One or more members of a class may sue

or be sued as representative parties on behalf of all

members only if:

(1) the class is so numerous that joinder of all

members is impracticable;

(2) there are questions of law or fact common to

the class;
20 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

23(a). A common question “must be of such a nature that it

is capable of classwide resolution—which means that

determination of its truth or falsity will resolve an issue that

is central to the validity of each one of the claims in one

stroke.” Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338, 350

(2011). By contrast, an individual question is one where

members of a proposed class will need to present evidence

that varies from member to member. See Tyson Foods, Inc.

v. Bouaphakeo, 577 U.S. 442, 453 (2016).

Second, the plaintiffs must show that the class fits into

one of three categories. See Fed. R. Civ. P. 23(b). To qualify

for the third category, Rule 23(b)(3), the district court must

find that “the questions of law or fact common to class

members predominate over any questions affecting only

individual members, and that a class action is superior to

other available methods for fairly and efficiently adjudicating

the controversy.” Fed. R. Civ. P. 23(b)(3).5“The

predominance inquiry asks whether the common,

(3) the claims or defenses of the representative

parties are typical of the claims or defenses of the

class; and

(4) the representative parties will fairly and

adequately protect the interests of the class.

5

 Rule 23(b)(3) provides in pertinent part:

A class action may be maintained if Rule 23(a) is

satisfied and if . . . (3) the court finds that the questions

of law or fact common to class members predominate

over any questions affecting only individual members,

and that a class action is superior to other available

methods for fairly and efficiently adjudicating the

controversy.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 21

aggregation-enabling, issues in the case are more prevalent or

important than the non-common, aggregation-defeating,

individual issues.” Tyson Foods, 577 U.S. at 453 (cleaned

up). The requirements of Rule 23(b)(3) overlap with the

requirements of Rule 23(a): the plaintiffs must prove that

there are “questions of law or fact common to class members”

that can be determined in one stroke, see Wal-Mart, 564 U.S.

at 349, in order to prove that such common questions

predominate over individualized ones, see Tyson Foods,

577 U.S. at 453–54. Therefore, courts must consider cases

examining both subsections in performing a Rule 23(b)(3)

analysis.

B

Before it can certify a class, a district court must be

“satisfied, after a rigorous analysis, that the prerequisites” of

both Rule 23(a) and 23(b)(3) have been satisfied. Gen. Tel.

Co. of Sw. v. Falcon, 457 U.S. 147, 161 (1982); Comcast,

569 U.S. at 35. “[P]laintiffs wishing to proceed through a

class actionmust actually prove—not simply plead—that their

proposed class satisfies each requirement of Rule 23,

including (if applicable) the predominance requirement of

Rule 23(b)(3),” and must carry their burden of proof “before

class certification.” Halliburton Co. v. Erica P. John Fund,

Inc., 573 U.S. 258, 275–76 (2014).

We have not yet prescribed the plaintiffs’ burden for

proving that the prerequisites of Rule 23 are satisfied. In the

absence of direction from Congress or the Constitution, it is

up to the court to prescribe the burden of proof. See Herman

& MacLean v. Huddleston, 459 U.S. 375, 389–90 (1983). To

do so, we must consider both the allocation of “the risk of

error between the litigants” and “the relative importance
22 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

attached to the ultimate decision.” Id. at 389 (quoting

Addington v. Texas, 421 U.S. 418, 423 (1979)). The

preponderance of the evidence standard allows both parties to

“share the risk of error in roughly equal fashion,” id. at 390

(quoting Addington, 421 U.S. at 423), while “[a]ny other

standard expresses a preference for one side’s interests,” id.

Therefore, the preponderance of the evidence standard is

“generally applicable in civil actions.” Id. By contrast, the

Court has “required proof by clear and convincing evidence

where particularly important individual interests or rights are

at stake,” such as termination of parental rights or involuntary

commitment proceedings. Id. at 389.

Applying this test here, the balance of interests in this

case favors prescribing the preponderance of the evidence

standard. The Supreme Court has made clear that Rule 23 is

consistent with the Rules Enabling Act and does not “abridge,

enlarge or modify any substantive right.” Shady Grove,

559 U.S. at 406–07 (citing 28 U.S.C. § 2072(b)). Rule 23

does not “change plaintiffs’ separate entitlements to relief nor

abridge defendants’ rights” and, instead, alters “only how the

claims are processed.” Id. at 408. Therefore, the Supreme

Court has concluded that the authorization of class actions is

substantively neutral, even though it may expose defendants

to the imposition of aggregate liability. Id. Because the

application of Rule 23 to certify a class does not alter the

defendants’ rights or interests in a substantive way, there is

no basis for applying a heightened standard of proof beyond

the traditional preponderance standard. We therefore join our

sister circuits in concluding that plaintiffs must prove the

facts necessary to carry the burden of establishing that the
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 23

prerequisites of Rule 23 are satisfied by a preponderance of

the evidence.6

In carrying the burden of proving facts necessary for

certifying a class under Rule 23(b)(3), plaintiffs may use any

admissible evidence. See Tyson Foods, 577 U.S. at 454–55

(explaining that admissibility of evidence at certificationmust

meet all the usual requirements of admissibility and citing to

Rules 401, 403, and 702 of the Federal Rules of Evidence). 

Plaintiffs frequently offer expert evidence, including

statistical evidence or class-wide averages, to prove that they

meet the prerequisites of Rule 23(b)(3). See id. at 455. 

Where, as here, a defendant did not raise a Daubert challenge

to the expert evidence before the district court,7

the defendant

forfeits the ability to argue on appeal that the evidence was

inadmissible, but may still argue that the evidence is not

capable of answering a common question on a class-wide

basis. See Comcast, 569 U.S. at 32 n.4; Tyson Foods,

577 U.S. at 458–59.

In order for the plaintiffs to carry their burden of proving

that a common question predominates, they must show that

the common question relates to a central issue in the

6

See In re Lamictal Direct Purchaser Antitrust Litig., 957 F.3d 184,

191 (3d Cir. 2020); In re Nexium Antitrust Litig., 777 F.3d 9, 27 (1st Cir.

2015); Messner v. Northshore Univ. HealthSystem, 669 F.3d 802, 811 (7th

Cir. 2012); Alaska Elec. Pension Fund v. Flowserve Corp., 572 F.3d 221,

228 (5th Cir. 2009); Teamsters Loc. 445 Freight Div. Pension Fund v.

Bombardier Inc., 546 F.3d 196, 202 (2d Cir. 2008).

7

In a class proceeding, defendants may challenge the reliability of an

expert’s evidence under Daubert v. Merrell Dow Pharmaceuticals, Inc.,

509 U.S. 579 (1993), and Rule 702 of the Federal Rules of Evidence. See

Tyson Foods, 577 U.S. at 459; see also Comcast, 569 U.S. at 32 n.4.
24 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

plaintiffs’ claim. See Wal-Mart, 564 U.S. at 349–50. 

Therefore, “[c]onsidering whether ‘questions of law or fact

common to class members predominate’ begins, of course,

with the elements of the underlying cause of action.” Erica

P. John Fund, Inc. v. Halliburton Co., 563 U.S. 804, 809

(2011) (quoting Fed. R. Civ. P. 23(b)(3)).

The claims at issue here are violations of section 1 of the

Sherman Antitrust Act, 15 U.S.C. § 15, and California’s

Cartwright Act, Cal. Bus. & Prof. Code §§ 16700 et seq.

8

The elements of a claim for such antitrust action are (i) the

existence of an antitrust violation; (ii) “antitrust injury” or

“impact” flowing from that violation (i.e., the conspiracy);

and (iii) measurable damages. See Big Bear Lodging Ass’n

v. Snow Summit, Inc., 182 F.3d 1096, 1101–02 (9th Cir.

1999); In re Hydrogen Peroxide Antitrust Litig., 552 F.3d

305, 311 (3d Cir. 2008), as amended (Jan. 16, 2009) (citing

15 U.S.C. § 15). “Antitrust injury” is “injury of the type the

antitrust laws were intended to prevent and that flows from

that which makes defendants’ acts unlawful.” Brunswick

Corp. v. Pueblo Bowl-O-Mat, Inc., 429 U.S. 477, 489 (1977). 

Damages are measured only after each plaintiff has

demonstratedthat the defendant’s conduct caused the plaintiff

8 The DPPs claim a violation of the Sherman Act, while the CFPs and

the EPPs allege violations of California’s antitrust law, theCartwright Act,

Cal. Bus. & Prof. Code, § 16700 et seq. The elements of a Cartwright Act

claim are “(1) the formation and operation of the conspiracy, (2) the

wrongful act or acts done pursuant thereto, and (3) the damage resulting

from such act or acts.” Marsh v. Anesthesia Servs. Med. Grp., Inc.,

132 Cal. Rptr. 3d 660, 670–71 (Cal. Ct. App. 2011) (cleaned up). Because

the analysis of a claim under the Cartwright Act “mirrors the analysis

under federal [antitrust] law,” we do not consider the Cartwright Act

claims separately from the federal antitrust claims. County of Tuolumne

v. Sonora Cmty. Hosp., 236 F.3d 1148, 1160 (9th Cir. 2001).
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 25

to suffer an antitrust injury. See In re Hydrogen Peroxide,

552 F.3d at 311.

Therefore, to prove there is a common question of law or

fact that relates to a central issue in an antitrust class action,

plaintiffs must establish that “essential elements of the cause

of action,” such as the existence of an antitrust violation or

antitrust impact, are capable of being established through a

common body of evidence, applicable to the whole class. Id.

(cleaned up). Here, the Tuna Purchasers claim that they can

establish the existence of antitrust impact through common

proof.

C

In making the determinations necessary to find that the

prerequisites of Rule 23(b)(3) are satisfied, the district court

must proceed “just as the judge would resolve a dispute about

any other threshold prerequisite for continuing a lawsuit.” In

re Initial Pub. Offerings Sec. Litig., 471 F.3d 24, 42 (2d Cir.

2006), decision clarified on denial of reh’g, 483 F.3d 70 (2d

Cir. 2007). This means that the court must make a “rigorous

assessment of the available evidence and the method or

methods by which plaintiffs propose to use the [class-wide]

evidence to prove” the common question in one stroke. In re

Hydrogen Peroxide, 552 F.3d at 312. In addition, the court

must find that this common question (i.e., the “common,

aggregation-enabling” issue) predominates over individual

issues. Tyson Foods, 577 U.S. at 453. The determination

whether expert evidence is capable of resolving a class-wide

question in one stroke may include “[w]eighing conflicting

expert testimony” and “[r]esolving expert disputes,” In re

Hydrogen Peroxide, 552 F.3d at 323–24, where necessary to

ensure that Rule 23(b)(3)’s requirements are met and the
26 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

“common, aggregation-enabling” issue predominates over

individual issues, Tyson Foods, 577 U.S. at 453.9

In determining whether the “common question”

prerequisite is met, a district court is limited to resolving

whether the evidence establishes that a common question is

capable of class-wide resolution, not whether the evidence in

fact establishes that plaintiffs would win at trial. While such

an analysis may “entail some overlap with the merits of the

plaintiff’s underlying claim,” Wal-Mart, 564 U.S. at 351, the

9 Not all expert evidence is capable of resolving a class-wide issue in

one stroke. Cf. Dissent at 70–71. Courts have frequently found that

expert evidence, while otherwise admissible under Daubert, was

inadequate to satisfy the prerequisites of Rule 23. For instance, a class did

not meet the prerequisites of Rule 23 where the expert evidence was

inadequate to prove an element of the claim for the entire class, see WalMart, 564 U.S. at 354, 356, 359 (holding that class members failed to

establish existence of common question with respect to Title VII claims

because they “provide[d] no convincing proof of a companywide

discriminatory pay and promotion policy”); where the damages evidence

was not consistent with the plaintiffs’ theory of liability, see Comcast, 569

U.S. at 35 (holding that at the class certification stage, “any model

supporting a plaintiff’s damages case must be consistent with its liability

case”); where the evidence contained unsupported assumptions, see In re

New Motor Vehicles Canadian Exp. Antitrust Litig., 522 F.3d 6, 29 (1st

Cir. 2008) (criticizing the unsupported assumption that, absent the

defendants’ anti-competitive conduct, there would have been an influx of

cars from Canada to United States sufficient to substantially decrease

national prices); or where the evidence demonstrated nonsensical results

such as false positives, i.e., injury to class members who could not

logically have been injured by a defendant’s conduct, see In re Rail

Freight Fuel Surcharge Antitrust Litig.-MDL No. 1869 (Rail Freight I),

725 F.3d 244, 252–55 (D.C. Cir. 2013) (vacating a certification order

where the plaintiffs’ expert evidence predicted that certain plaintiffs had

been injured by a price-fixing conspiracy even though they operated under

fixed-price contracts and were not exposed to overcharges caused by the

conspiracy).
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 27

“[m]erits questions may be considered [only] to the extent []

that they are relevant to determining whether the Rule 23

prerequisites for class certification are satisfied,” Amgen Inc.

v. Conn. Ret. Plans & Tr. Funds, 568 U.S. 455, 466 (2013);

see also Ellis v. Costco Wholesale Corp., 657 F.3d 970, 983

n.8 (9th Cir. 2011). “Rule 23 grants courts no license to

engage in free-ranging merits inquiries at the certification

stage.” Amgen, 568 U.S. at 466.

A district court must also resolve disputes about historical

facts if necessary to determine whether the plaintiffs’

evidence is capable of resolving a common issue central to

the plaintiffs’ claims.10 For instance, in a case in which a

nationwide class of plaintiff employees alleged nationwide

discrimination by their employer, we held that a district court

had to resolve factual disputes at certification regarding

whether decisions regarding promotions were made at the

local level or by upper management. See Ellis, 657 F.3d at

983–84 & n.7. We reasoned that if such decisions were made

only at the local level, plaintiffs “would face an exceedingly

difficult challenge in proving that there are questions of fact

and law common to the nationwide class.” Id. at 983–84. 

Nevertheless, the district court was not required to resolve

factual disputes regarding ultimate issues on the merits, such

as “whether women were in fact discriminated against” or

whether the defendant “does in fact have a culture of gender

stereotyping and paternalism.” Id. at 983; see also id. at 983

n.8. Resolving such issues would “put the cart before the

horse” by requiring plaintiffs to show at certification that they

will prevail on the merits. Amgen, 568 U.S. at 460.

10 The district court’s findings at the certification stage “do not bind

the fact-finder on the merits.” In re Hydrogen Peroxide, 552 F.3d at 318.
28 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Therefore, a district court cannot decline certification

merely because it considers plaintiffs’ evidence relating to the

common question to be unpersuasive and unlikely to succeed

in carrying the plaintiffs’ burden of proof on that issue. See

id. at 459–60. Rather, Tyson Foods established the rule that

if “each class member could have relied on [the plaintiffs’

evidence] to establish liability if he or she had brought an

individual action,” and the evidence “could have sustained a

reasonable jury finding” on the merits of a common question,

Tyson Foods, 577 U.S. at 455, then a district court may

conclude that the plaintiffs have carried their burden of

satisfying the Rule 23(b)(3) requirements as to that common

question of law or fact.11In Tyson Foods, for instance, the

Court held that if the class members had pursued individual

lawsuits, each could have relied on the expert evidence

purporting to show how long it took to don and doff

protective equipment. Tyson Foods, 577 U.S. at 456–57. 

Accordingly, the Court concluded that such expert evidence

was capable of answering a common question for the entire

class in one stroke, and could reasonably sustain a jury

11 Senne v. Kansas City Royals Baseball Corp. referenced Tyson

Foods’s rule that a district court may deny the use of admissible expert

evidence to meet the requirements of Rule 23(b)(3) only if “‘no

reasonable juror’ could find it probative of whether an element of liability

was met,” and then stated in passing that “Tyson expressly cautioned that

this rule should be read narrowly and not assumed to apply outside of the

wage and hour context.” 934 F.3d 918, 947 & n.27 (9th Cir. 2019) (citing

Tyson Foods, 577 U.S. at 459–60). But Tyson Foods contains no such

limitation; rather, it declined to adopt “broad and categorical rules

governing the use of representative and statistical evidence in class

actions,” and indicated that district courts should evaluate the sufficiency

of plaintiffs’ evidence on a case-by-case basis, depending on the purpose

for which the expert evidence is being introduced and the underlying

cause of action. 577 U.S. at 459–60. Accordingly, we disapprove this

dictum in Senne, 934 F.3d at 947 n.27.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 29

verdict in favor of the plaintiffs, even though a jury could still

decide that the evidence was not persuasive. Id. at 459–60;

see also id. at 457 (explaining that the question whether the

expert’s “study was unrepresentative or inaccurate” was

“itself common to the claims made by all class members”). 

The rule that the evidence need merely be capable of

resolving a common question on a class-wide basis holds true

whether the common question concerns an element of

plaintiffs’ claim, see Amgen, 568 U.S. at 468–69 (materiality

in a Rule 10b-5 action), or a fact that must be determined to

establish liability, see Tyson Foods, 577 U.S. at 450 (time

spent donning and doffing protective equipment per week).

Nor can a district court decline to certify a class that will

require determination of some individualized questions at

trial, so long as such questions do not predominate over the

common questions. See Fed. R. Civ. P. 23(b)(3). “When one

or more of the central issues in the action are common to the

class and can be said to predominate, the action may be

considered proper under Rule 23(b)(3) even though other

important matters will have to be tried separately, such as

damages or some affirmative defenses peculiar to some

individual class members.” Tyson Foods, 577 U.S. at 453

(internal quotation marks omitted). Thus, Halliburton

concluded that so long as plaintiffs could show that their

evidence is capable of proving the prerequisites for invoking

the presumption of reliance (a key element in a securities

class action) on a class-wide basis, the fact that the

defendants would have the opportunity at trial to rebut that

presumption as to some of the plaintiffs did not raise

individualized questions sufficient to defeat predominance. 

573 U.S. at 276. “That the defendant might attempt to pick

off the occasional class member here or there through
30 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

individualized rebuttal does not cause individual questions to

predominate.” Id.

When individualized questions relate to the injury status

of class members, Rule 23(b)(3) requires that the court

determine whether individualized inquiries about such

matters would predominate over common questions. See

Cordoba v. DIRECTV, LLC, 942 F.3d 1259, 1277 (11th Cir.

2019).12In an analogous context, we have held that a district

court is not precluded from certifying a class even if plaintiffs

may have to prove individualized damages at trial, a

conclusion implicitly based on the determination that such

individualized issues do not predominate over common ones. 

Vaquero v. Ashley Furniture Indus., Inc., 824 F.3d 1150,

1155 (9th Cir. 2016); see also Pulaski & Middleman, LLC v.

Google, Inc., 802 F.3d 979, 988 (9th Cir. 2015); In re

Urethane, 768 F.3d 1245, 1255 (10th Cir. 2014) (“The

presence of individualized damages issues” does not preclude

a court from certifying a class because “[c]lass-wide proof is

not required for all issues”).

Therefore, we reject the dissent’s argument that Rule 23

does not permit the certification of a class that potentially

includes more than a de minimis number of uninjured class

members. Dissent at 77. This position is inconsistent with

Rule 23(b)(3), which requires only that the district court

determine after rigorous analysis whether the common

12 Because the Supreme Court has clarified that “[e]very class

member must have Article III standing in order to recover individual

damages,” TransUnion LLC v. Ramirez, 141 S. Ct. 2190, 2208 (2021),

Rule 23 also requires a district court to determine whether individualized

inquiries into this standing issue would predominate over common

questions, see Cordoba, 942 F.3d at 1277.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 31

question predominates over any individual questions,

including individualized questions about injury or entitlement

to damages. See Fed. R. Civ. P. 23(b)(3).13

A district court is in the best position to determine

whether individualized questions, including those regarding

class members’ injury, “will overwhelm common ones and

render class certification inappropriate under Rule 23(b)(3).” 

Halliburton, 573 U.S. at 276; see also Ruiz Torres, 835 F.3d

at 1137 (stating that “the district court is well situated to

winnow out” a fortuitously non-injured subset of class

members). We “uphold a district court’s determination that

falls within a broad range of permissible conclusions.” Hung

Lam v. City of San Jose, 869 F.3d 1077, 1084 (9th Cir. 2017)

13 The dissent focuses on policy reasons why district courts should

refrain from certifying classes that may include more than a de minimis

number of uninjured class members. Dissent at 64, 75, 77–78. But we are

bound to apply Rule 23(b)(3) as written, regardless of policy preferences. 

And contrary to the dissent’s assertion, our conclusion that courts must

apply Rule 23(b)(3) on a case-by-case basis, rather than rely on a per se

rule that a class cannot be certified if it includes more than a de minimis

number of uninjured class members, is consistent with the approach taken

by our sister circuits. Dissent at 78. Neither of the two cases cited by the

dissent, In re Rail Freight Fuel Surcharge Antitrust Litig.-MDL No. 1869

(Rail Freight II), 934 F.3d 619 (D.C. Cir. 2019) and In re Asacol Antitrust

Litig., 907 F.3d 42 (1st Cir. 2018), adopted a per se rule. Rather, based on

the particular facts of the cases before them, our sister circuits held that

Rule 23(b)(3)’s predominance requirement is not satisfied when the need

to identify uninjured class members “will predominate and render an

adjudication unmanageable.” In re Asacol Antitrust Litig., 907 F.3d at

53–54; see also Rail Freight II, 934 F.3d at 625 (holding that a district

court did not abuse its discretion in denying class certification where the

plaintiffs “proposed no further way—short offull-blown, individual trials”

to determine the common question of whether class members were

injured).
32 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

(quoting Kode v. Carlson, 596 F.3d 608, 612 (9th Cir.

2010)).14

III

We now turn to the Tuna Suppliers’ arguments and

consider them in light of this legal framework. We begin

with the DPP class, which is the focus of the Tuna Suppliers’

14 Nevertheless, a court must consider whether the possible presence

of uninjured class members means that the class definition is fatally

overbroad. When “a class is defined so broadly as to include a great

number of members who for some reason could not have been harmed by

the defendant’s allegedly unlawful conduct, the class is defined too

broadly to permit certification.” Messner, 669 F.3d at 824; see also Mazza

v. Am. Honda Motor Co., 666 F.3d 581, 596 (9th Cir. 2012) (holding that

the class definition in a false advertising action was fatally overbroad

where many members learned that the advertising was misleading before

purchase or had never been exposed to the allegedly misleading

advertisements); In re Asacol, 907 F.3d at 55–58 (holding that the class

did not meet Rule 23(b)(3) requirements because the plaintiffs’ evidence

showed that thousands of plaintiffs who were loyal to brand-name drugs

would not have purchased the generic drugs that were the subject of the

price-fixing conspiracy). In such a case, the court may redefine the

overbroad class to include only those members who can rely on the same

body of common evidence to establish the common issue. See, e.g.,

Mazza, 666 F.3d at 596 (holding that false advertising “class must be

defined in such a way as to include only members who were exposed to

advertising that is alleged to be materially misleading”). A court may not,

however, create a “fail safe” class that is defined to include only those

individuals who were injured by the allegedly unlawful conduct. See Ruiz

Torres, 835 F.3d at 1138 n.7 (internal quotation marks omitted). “Such

a class definition is improper because a class member either wins or, by

virtue of losing, is defined out of the class and is therefore not bound by

the judgment.” Messner, 669 F.3d at 825. But, ultimately, the problem

of a potentially “over-inclusive” class “can and often should be solved by

refining the class definition rather than by flatly denying class certification

on that basis.” Id.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 33

arguments. In order to prevail on their antitrust claim, the

DPP class must prove that the Tuna Suppliers engaged in a

conspiracy (an antitrust violation), which resulted in antitrust

impact in the form of higher prices paid by each member of

the class, which in turn led to measurable damages. The

question whether each member of the DPP class suffered

antitrust impact “is central to the validity of each one of the

[DPP] claims.” Wal-Mart, 564 U.S. at 350. The central

questions on appeal are whether the expert evidence

presented by the DPPs is capable of resolving this issue “in

one stroke,” id., and whether this common question

predominates over any individualized inquiry. We conclude

that the district court did not abuse its discretion in certifying

the class.

A

The centerpiece of the DPPs’ claim that each member of

the class suffered antitrust impact is economist Dr. Russell

Mangum’s expert testimony and report. According to his

testimony and report,Dr.Mangumreviewed a comprehensive

range of available information to develop an understanding of

the nature of the market at issue and the details of the Tuna

Suppliers’ price-fixing conspiracy. That information

included court filings, the Tuna Suppliers’ guilty pleas,

discovery materials such as the Tuna Suppliers’ business

records concerning their sales of packaged tuna, deposition

testimony, publicly available information regarding the tuna

industry, and data regarding supply and demand factors that

affect the manufacture, sale and consumption of packaged

tuna such as raw material prices and details about customer

preferences.
34 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

After examining the economic structure of the tuna

market and the available record evidence concerning the Tuna

Suppliers’ behavior, Dr. Mangum determined that the

packaged tuna market was conducive to price-fixing, given

the Tuna Suppliers’ dominance in the market, the attendant

barriers to entry for competitors, the Tuna Suppliers’ use of

price lists for their products, and other characteristics of the

packaged tuna industry. According to Dr. Mangum, these

findings supported a baseline economic theory that the Tuna

Suppliers’ collusive behavior would affect the DPPs on a

class-wide basis. Dr. Mangum then used a number of

different econometric tools to evaluate whether quantitative

evidence supported this theory.15

Dr. Mangum first performed a pricing correlation test,

which demonstrated that the prices of the Tuna Suppliers’

products moved up or down together regardless of product or

customer type, and thus supported the proposition that the

Tuna Suppliers’ collusion had a common, supra-competitive

impact on their prices. Based on this evidence, Dr. Mangum

concluded that the Tuna Suppliers’ collusion would result in

higher prices that would affect direct purchasers on a classwide basis, which was consistent with his original theory. 

This finding is also consistent with “the prevailing

[economic] view [that] price-fixing affects all market

participants, creating an inference of class-wide impact even

when prices are individually negotiated.” In re Urethane,

768 F.3d at 1254.

15 Econometrics is “the application of statistical methods to economic

data . . . to draw inferences about economic relationships from observed

data on market outcomes [i.e., price], even when those outcome are the

result of complex interactions among numerous economic forces.” 

Econometrics at 1.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 35

To further explore whether the DPPs were subject to an

overcharge caused by the price-fixing conspiracy (rather than

by other variables that could affect prices) on a class-wide

basis, Dr. Mangum constructed a statistical model using a

multiple regression analysis. Regression analyses are used to

determine “the relationship between an unknown [dependent]

variable [such as price] and one or more independent

variables [e.g., transaction characteristics, and supply and

demand factors] that are thought to impact the dependent

variable.” Id. at 1260 (quotation marks omitted) (citing

Michael J. Saks, et al., Reference Manual on Scientific

Evidence 179, 181 (2d ed. 2000)). If a regression model uses

“appropriate independent [or explanatory] variables,” it can

test and isolate the extent to which the actual prices paid by

plaintiffs are higher because of a defendant’s collusive

behavior. Id. Assuming Dr. Mangum’s regression model met

this standard, it could provide further evidence that the DPPs

were impacted by the Tuna Suppliers’ collusion on a classwide basis.

In simple terms, Dr. Mangum first aggregated (or

“pooled”) the actual tuna sale transaction data for the Tuna

Suppliers’ sales to the DPPs during both the alleged

conspiracy period and during benchmark periods before and

after the conspiracy. Dr. Mangum then identified a number

of variables (referred to as independent or explanatory

variables) that could affect the price of tuna, including

product characteristics, input costs, customer type, and

variables related to consumer preference and demand, such as

disposable income, seasonal effects, and geography. The

model then isolated (or “controlled for”) the effect of these

explanatory variables on the prices paid by DPPs, which

allowed the model to isolate the effect that the conspiracy by

itself had on the prices paid by DPPs. When all the tuna sale
36 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

transactions were aggregated, and the explanatory variables

(other than the price-fixing conspiracy) were controlled for,

the model showed that the DPPs paid 10.28 percent more for

tuna during the conspiracy period than they did during the

benchmark periods. Dr. Mangum labeled this 10.28 percent

as the “overcharge,” meaning the common amount paid by

the DPPs resulting from the collusive behavior alone. This

result was statistically significant, meaning that there was a

less than five percent chance that the higher prices during the

price-fixing conspiracy was a product of chance. Thus, by

isolating the common overcharge amount, Dr. Mangum’s

regression model was further confirmation of his theory that

the Tuna Suppliers’ collusion had a class-wide effect.16

Dr. Mangum performed several tests (which he referred

to as “robustness checks”) to confirm that his regression

model was an appropriate tool to be used by the entire DPP

class to show common impact. These tests were used to

confirm the reliability of the model, and, according to

Dr. Mangum, the test results supported his ultimate

conclusion that the model could be used to show class-wide

16 The dissent argues that Dr. Mangum’s opinion is not persuasive

because large retailers have bargaining power and can extract price

discounts, promotional credits, and rebates. Dissent at 72–73. As the

dissent concedes, Dissent at 73 & n. 5, Dr. Mangum took these issues into

account (to the extent that the Tuna Suppliers provided relevant data). 

After doing so, Dr. Mangum ran the regression model using both gross

and net prices and determined that his regression model continued to

produce a statistically significant overcharge. Dr. Mangum therefore

reasoned that discounts and promotions did not affect his pooled model or

his conclusion of class-wide impact. Although the dissent argues that (in

the dissent’s view) Dr. Mangum did not consider price discounts,

promotional credits, and rebates “adequately,” Dissent at 73 & n. 5, the

persuasiveness of Dr. Mangum’s analysis is not at issue at this phase of

the proceeding.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 37

injury. First, Dr. Mangum changed the model to evaluate the

overcharge specific to each individual defendant. The results

showed that prices were still elevated above competitive

levels during the collusion period. Second, Dr. Mangum

changed the model to evaluate the overcharge specific to

certain products with different characteristics, such as fish

type and package type. These tests showed that each type of

product tested was impacted to a similar degree. Third,

Dr. Mangum changed the model to evaluate the overcharge

based on customer types.17 This test showed that there were

large, statistically significant overcharges for every customer

type. These robustness checks confirmed Dr. Mangum’s

theory that the DPPs paid an overcharge during the

conspiracy period. Finally, Dr. Mangum used the output of

the pooled regression model to predict the but-for prices (i.e.,

what the price of tuna during the conspiracy period would

have been without the overcharge caused by the conspiracy),

and compared these predicted but-for prices to the actual

prices paid by the DPP class. This comparison showed that

94.5 percent of the purchasers had at least one purchase

above the predicted but-for price, which again provided

further evidence that the conspiracy had a common impact on

all or nearly all the members of the DPP class.18 Dr. Mangum

17 Direct purchasers were grouped into categories called customer

types, which included Retail, Club, Special Market, Food Service, Mass

Merchandise, Discount, and e-Commerce.

18 According to Dr. Mangum, the purpose of this robustness test was

to demonstrate that his regression model was sound. Contrary to the

dissent’s assertion, Dissent at 66, Dr. Mangum did not “suggest” that

5.5 percent of the class were uninjured. Rather, Dr. Mangum concluded

that each class member was injured by supra-competitive prices, and used

a different methodology for calculating damages for each member of the

class. See infra at n.19. The Tuna Suppliers do not develop the argument
38 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

therefore concluded that his aggregated regression model

provided econometric evidence that the conspiracy resulted

in higher prices paid by all or nearly all DPPs. According to

Dr. Mangum, the results were strong evidence of common,

class-wide antitrust impact.19

In sum, Dr. Mangum’s findings about the tuna market and

the Tuna Suppliers’ collusive behavior, his pricing correlation

test, his regression model, and his robustness checks all

confirmed his theory that the conspiracy resulted in

substantial price impacts, and that the impact was common to

the DPPs during the collusion period.

B

The Tuna Suppliers attacked Dr. Mangum’s expert report

on multiple fronts, but primarily relied on their rebuttal

expert, economist Dr. John Johnson, who made multiple

criticisms of Dr. Mangum’s methodology. The essence of

that the results of this robustness test preclude certification of the class as

currently defined. Therefore, we do not address this issue here. See

United States v. Sineneng-Smith, 140 S. Ct. 1575, 1578 (2020); see also

Tyson Foods, 577 U.S. at 460 (declining to reach a similar issue).

19 Although the regression model primarily served as evidence of

class-wide antitrust impact, Dr. Mangum used the overcharge derived

from the regression model to estimate class-wide damages. This estimate

was developed by multiplying the overcharge estimate of 10.28 percent by

the appropriate sales volume for the defendants, adjusted by several

pertinent factors. Dr. Mangumused the same method to estimate damages

for each of the class representatives identified in the complaint. The Tuna

Suppliers do not challenge Dr. Mangum’s damages methodology. Thus,

the dissent’s contention that the court has created a “sweeping rule that

gives a free pass to the intractable problem of highly individualized

damages analyses” misses the mark. Dissent at 74.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 39

Dr. Johnson’s critique was that it was not statistically

appropriate to use a pooled regression model for transactions

in the tuna market, given the multiple individualized

differences among class members, such as disparities in

negotiating tactics and bargaining power. Dr. Mangum’s use

of pooled data, Dr. Johnson alleged, masked these individual

differences among class members. Thus, Dr. Johnson

claimed, Dr. Mangum’s conclusion that the conspiracy had a

class-wide impact based on a uniform overcharge did not

reflect the real world.

Dr. Johnson supported this allegation on several grounds. 

First, Dr. Johnson claimed that a statistical tool called a Chow

test20

shows that the data relating to tuna transactions should

not be pooled due to individual differences in each

purchaser’s transactions. Second, Dr. Johnson criticized

Dr. Mangum’s calculation that 94.5 percent of DPPs whose

transactional data were included in the model had at least one

purchase at a price above the predicted but-for price. 

According to Dr. Johnson, this calculation was misleading

because it was premised on what Dr. Johnson characterized

as the faulty assumption that all direct purchasers paid the

same 10.28 percent overcharge throughout the proposed class

period. Instead, Dr. Johnson performed his own test of

Dr. Mangum’s model. As part of this test, Dr. Johnson

changed the model to evaluate overcharge based on each

individual customer. According to Dr. Johnson, the test

showed that of the 604 direct purchasers who bought from the

Tuna Suppliers during the proposed class period, the model

did not estimate a positive and statistically significant

20 A Chow test is a statistical test designed to “determine whether it

is appropriate to pool potential subgroups when estimating the average

effect of the alleged conspiracy.” Econometrics at 358.
40 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

overcharge (attributable to the conspiracy) for 169 direct

purchasers (or 28 percent). Therefore, Dr. Johnson argued

that the plaintiffs could not rely on the model to demonstrate

class-wide impact of the conspiracy.21

Dr. Johnson made several additional critiques in arguing

that Dr. Mangum’s model was not capable of demonstrating

class-wide impact. First, Dr. Johnson argued that

Dr. Mangum’s model showed false positives. According to

Dr. Johnson, an application of Dr. Mangum’s regression

model showed that several DPP class members had paid an

overcharge when they purchased tuna products from nondefendants, i.e., tuna suppliers who had not participated in the

conspiracy. Second, Dr. Johnson attacked the reliability of

Dr. Mangum’s model because Dr. Mangum’s model selected

time periods that did not precisely match the class periods in

the DPPs’ complaint. Finally, Dr. Johnson criticized

Dr. Mangum’s use of a cost index (a calculated measure of

costs for all the Tuna Suppliers) as one of the explanatory

variables in his model, rather than using actual accounting

cost data. According to Dr. Johnson, the use of a cost index

inappropriately assumed that the Tuna Suppliers’ costs

responded in a like way to supply and demand factors.

In rebuttal, Dr. Mangum rejected Dr. Johnson’s premise

that a pooled, aggregated model was inappropriate to use in

21 Dr. Johnson’s test attempted to show that Dr. Mangum’s model was

flawed because 169 direct purchasers could not rely on the model to show

antitrust impact due to the fact (as Dr. Mangum subsequently explained)

that some purchasers had no or too few transactions during the precollusion benchmark period to generate statistically significant results. 

Contrary to the dissent’s claim, Dissent at 66, Dr. Johnson did not show

that 28 percent of the class potentially suffered no injury. See infra

Section IV.B.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 41

this case. Dr. Mangum explained that his technique was a

well-known and well-accepted method for examining

antitrust impact in markets with individualized differences

among purchasers. According to Dr. Mangum, both of the

bases for Dr. Johnson’s challenges to the use of a pooled

regression model failed. First, Dr. Mangum claimed that a

Chow test should not be used in the manner employed by

Dr. Johnson in his report. According to Dr. Mangum,

Dr. Johnson’s Chow test was “designed to fail,” meaning that

in this context, the test results would always show that the

data relating to tuna transactions should not be pooled. 

Second, Dr. Mangum asserted that the record contained

insufficient transaction data for Dr. Johnson’s test of the

regression model to yield meaningful results. For example,

Dr. Mangum acknowledged that the model, as changed by

Dr. Johnson to consider purchasers on an individual basis,

could not estimate a positive and statistically significant

overcharge for 169 direct purchasers. But according to

Dr. Mangum, no regression model could yield a statistically

significant estimate for many of those 169 direct purchasers

on such an individual purchaser-by-purchaser basis, because

61 of those purchasers did not make any purchases during the

benchmark periods, and many of the other purchasers had not

undertaken a sufficient number of transactions during either

the benchmark periods or collusion period to yield

statistically significant results. And logically, Dr. Mangum

asserted, given the evidence that the defendants were able to

inflate prices generally through the conspiracy, that the tuna

market was susceptible to collusion, and that the model

showed a robust, statistically significant impact of the pricefixing scheme on the tuna market, even the DPP class

members for whom Dr. Johnson’s test did not yield a

positive, statistically significant overcharge should be able to

rely on the pooled regression model as evidence of impact. 
42 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Therefore, according to Dr. Mangum, Dr. Johnson erred in

concluding that the regression model had no relevance for

that 28 percent of class members.

Dr. Mangum also rebutted Dr. Johnson’s additional

critiques. With respect to Dr. Johnson’s claim that the

regression model yielded false positives, Dr. Mangum

explained that overcharges imposed by non-defendant tuna

suppliers (who were not part of the conspiracy) were not false

positives but were caused by the “umbrella effect.” This term

refers to an economic observation that when many suppliers

engage in a conspiracy to raise prices, non-conspirators may

raise their prices to supra-competitive levels because of the

conspirator’s dominant market power. See ABA Section of

Antitrust Law, Proving Antitrust Damages: Legal &

Economic Issues 226 (2d ed. 2010). Dr. Mangum also argued

that Dr. Johnson’s claim of false positives was based on an

erroneous analysis of the tuna market. According to

Dr. Mangum, Dr. Johnson incorrectly claimed that two of the

individual DPPs (Sysco and U.S. Foods) purchased tuna from

non-defendant suppliers because both of those class members

actually purchased tuna that was produced by the Tuna

Suppliers and merely sold through a middleman. 

Dr. Mangum defended his selection of time periods relating

to the model, claiming he narrowed the class period based on

his analysis of the evidence in the case. Finally, Dr. Mangum

rejected Dr. Johnson’s critique of his use of cost indexes. 

Dr. Mangum asserted that costs indexes were statistically

superior to using individual cost accounting data. He noted

that one of the robustness tests he performed on the data

showed that using defendant-specific cost structures

confirmed the results of the pooled model. And he asserted

that it was preferable to use his cost index for determining

competitive market prices based on market supply and
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 43

demand conditions, rather than relying on cost data derived

from the Tuna Suppliers’ individual approaches to cost

accounting.

C

In considering whether the DPPs’ evidence was capable

of establishing antitrust impact for the class as a whole, the

district court reviewed Dr. Mangum’s expert testimony and

report, the rebuttal testimony and report by Dr. Johnson, and

Dr. Mangum’s reply, and then addressed the parties’ disputes. 

In doing so, the district court did not make any legal or

factual error.

First, the district court consideredDr.Johnson’s argument

that Dr. Mangum’s pooled regression model masked

differences between purchasers, and that when the overcharge

is determined for individual DPP class members the model

did not show a positive, statistically significant impact for

some 28 percent of the class. After reviewing each of the

experts’ analyses, the district court credited Dr. Mangum’s

rebuttal of Dr. Johnson’s critique. Even if the model (when

modified by Dr. Johnson to evaluate individual purchasers)

did not yield a positive, statistically significant overcharge for

some purchasers who had no or too few transactions during

the pre-collusion benchmark period, the district court

concluded that those purchasers could still rely on the pooled

regression model as evidence of the conspiracy’s impact on

similarly situated class members. The court further noted that

other evidence in the record, including the guilty pleas and

market characteristics, showed that class members suffered a

common impact.
44 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

The district court also considered Dr. Johnson’s argument

that the Chow test showed that Dr. Mangum’s model cannot

be applied to all defendants. The court acknowledged that

failure of a statistical test used to determine whether a

regression is appropriate should be taken seriously, and could

lead a court to reject the model at the class certification stage

as not capable of providing class-wide proof. But it also

noted that most regressions models will fail one or more tests

if enough are run, even if the model itself is statistically

sound. Because there was a rational basis for Dr. Mangum’s

use of the pooled regression model to demonstrate class-wide

impact, the court concluded the failure of the Chow test did

not require the court to reject the model.

The district court rejected Dr. Johnson’s additional

arguments. With respect to Dr. Johnson’s claim that the false

positives in Dr. Mangum’s model rendered the model

unreliable, the court credited Dr. Mangum’s explanation that

the false positives could be explained by the umbrella effect

and that Dr. Johnson had erroneously concluded that some

tuna was supplied by non-defendants when in fact the tuna

was supplied by defendants. The district court also addressed

the dispute over Dr. Mangum’s selection of the time period

for the class, and concluded that Dr. Mangum’s narrowing of

the time frame bolstered the reliability of the model. Finally,

the district court rejected Dr. Johnson’s critique of

Dr. Mangum’s use of a cost index, rather than actual

accounting cost data. The court credited Dr. Mangum’s

explanation as to why the use of such an index provided more

reliable results than actual cost accounting data, and

concluded that his use of a cost index did not undermine the

reliability of his methodology or model.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 45

After resolving each dispute between the experts, the

district court acknowledged that the defendants’ critique of

Dr. Mangum’s model could be persuasive to a jury at trial. 

But the district court recognized that at this stage of the

proceedings, its task was to determinewhether Dr. Mangum’s

evidence was capable of showing class-wide impact, not to

reach a conclusion on the merits of the DPPs’ claims. After

weighing the evidence put forth by the DPPs, including the

regression model, the correlation tests, the record evidence

and the guilty pleas and admissions entered in this case, the

district court concluded there was sufficient evidence to show

common questions predominated as to common impact. 

Therefore, it ruled that this prerequisite to Rule 23(b)(3) was

met.

We conclude that the district court did not abuse its

discretion in reaching this conclusion. The court conducted

a rigorous analysis of the expert evidence presented by the

parties. The district court did not err legally or factually in

concluding that Dr. Mangum’s pooled regression model,

along with other evidence, is capable of answering the

question whether there was antitrust impact due to the

collusion on a class-wide basis, thus satisfying this

prerequisite of Rule 23(b)(3).

IV

We now turn to the Tuna Suppliers’ claims that the

district court abused its discretion in determining that the

evidence presented by the DPPs proved: (1) that the element

of antitrust impact is capable of being established class-wide
46 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

through common proof, and (2) that this common question

predominates over individual questions.22

A

The Tuna Suppliers’ main argument is that the district

court abused its discretion in determining that Dr. Mangum’s

model is capable of proving common impact for all class

members. According to the Tuna Suppliers, Dr. Mangum’s

evidence is not a permissible method of proving class-wide

liability because the regression model uses “averaging

assumptions,” meaning that the model assumes that all DPPs

were overcharged by the same uniform percentage

(10.28 percent). These averaging assumptions, according to

the Tuna Suppliers, “paper over” individualized differences

among class members. Because the tuna market is

characterized by individualized negotiations and different

bargaining power among the purchasers, the Tuna Suppliers

claim it is fundamentally impossible to show common proof

of injury. To support this argument, the Tuna Suppliers note

that the DPPs who pursued their antitrust claims individually

did not rely on a pooled regression model but used actual cost

data and claimed an individualized overcharge rate. Given

the nature of the tuna market, the Tuna Suppliers conclude,

22 The Tuna Suppliers do not challenge the district court’s

gatekeeping function under Daubert, to ensure that Dr. Mangum’s

evidence was not “statistically inadequate or based on implausible

assumptions.” Tyson Foods, 577 U.S. at 459. And contrary to the

dissent’s argument, Dissent at 69, the district court did not merely

determine that Dr. Mangum’s evidence was admissible under Daubert. 

Rather, it subjected the evidence to a rigorous examination with full

consideration of Dr. Johnson’s critique. Therefore, the dissent’s assertion

that the district court committed the same error as the district court in Ellis

is misplaced. Dissent at 68–69.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 47

Dr. Mangum’s model cannot meet the prerequisites of

Rule 23(b)(3).

To the extent that the Tuna Suppliers argue that pooled

regressionmodels involve improper “averaging assumptions”

and therefore are inherently unreliable when used to analyze

complex markets, we disagree. In antitrust cases, regression

models have been widely accepted as a generally reliable

econometric technique to control for the effects of the

differences among class members and isolate the impact of

the alleged antitrust violations on the prices paid by class

members.23

See, e.g., Econometrics at 1. Further, Tyson

Foods rejected any categorical exclusion of representative24

or statistical evidence. 577 U.S. at 459–60. Therefore, any

categorical argument that a pooled regression model cannot

control for variables relating to the individualized differences

among class members must be rejected.

23 See, e.g., Kleen Prod. LLC v. Int’l Paper Co., 831 F.3d 919, 929

(7th Cir. 2016); In re Urethane, 768 F.3d at 1263; Cordes & Co. Fin.

Servs. v. A.G. Edwards & Sons, Inc., 502 F.3d 91, 97, 107 (2d Cir. 2007);

Hemmings v. Tidyman’s Inc., 285 F.3d 1174, 1188–89 (9th Cir. 2002); In

re Linerboard Antitrust Litig., 305 F.3d 145, 153 (3d Cir. 2002).

24 Although the Tuna Suppliers refer to Dr. Mangum’s regression

model as “representative evidence,” that term is imprecise. As explained

in Tyson Foods, representative evidence generally refers to a sample that

represents the class as a whole. See 577 U.S. at 454–55. Thus, Tyson

Foods concluded that each individual in a class could rely on exemplars

of persons donning and doffing protective equipment to prove the amount

of time each spent donning and doffing; this sample was claimed to be

representative of all members of the class. See id. By contrast, a

regression model analyzes available data to determine the degree to which

a known variable, such as collusion, affected an unknown variable, such

as price, while eliminating the effect of other variables.
48 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

To the extent the Tuna Suppliers and the dissent raise the

more focused argument that, in this case, the model’s output

(estimating that the Tuna Suppliers’ conspiracy resulted in a

10.28 percent overcharge for the entire class) cannot

plausibly serve as common evidence for all class members

given the individualized differences among those class

members, we again disagree.25It is not implausible to

conclude that a conspiracy could have a class-wide impact,

“even when the market involves diversity in products,

marketing, and prices,” especially “where, as here, there is

evidence that the conspiracy artificially inflated the baseline

for price negotiations.” In re Urethane, 768 F.3d at 1254–55. 

As the Tenth Circuit explained, a district court could

reasonably conclude “that price-fixing would have affected

the entire market, raising the baseline prices for all buyers.” 

Id. at 1255. In other words, it is both logical and plausible

that the conspiracy could have raised the baseline prices for

all members of the class by roughly ten percent. The district

court did not abuse its discretion in so concluding.

The dissent argues that Dr. Mangum’s expert opinion

“flies against common sense and empirical evidence,”

because large retailers like Walmart likely would have used

their bargaining power to negotiate lower prices, and thus

may not have paid higher prices because of the Tuna

Suppliers’ collusion. Dissent at 72. But the district court is

not free to prefer its own views about the economics of the

25 To the extent the Tuna Suppliers challenged the model’s inputs, the

district court considered and rejected Dr. Johnson’s critique that some of

the model’s inputs (i.e., the use of a cost index and Dr. Mangum’s

selection of time periods) rendered the model incapable of demonstrating

class-wide impact. Cf. In re Lamictal, 957 F.3d at 194 (holding that the

district court abused its discretion in certifying class because it failed to

scrutinize each expert’s data).
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 49

tuna market over the statistical evidence submitted by the

plaintiffs, and here the regression model controlled for the

variables identified by the dissent. Indeed, Dr. Mangum

provided an individualized overcharge estimate for Walmart

when he changed the model to evaluate the overcharge based

on customer types. This test showed that Walmart paid

statistically significant overcharges because of the

conspiracy. Provided that the evidence is admissible and,

after rigorous review, determined to be capable of

establishing antitrust impact on a class-wide basis, it is for the

jury, not the court, to decide the persuasiveness of

Dr. Mangum’s evidence in light of “common sense and

empirical evidence.”

The Tuna Suppliers rely on In re New Motor Vehicles

Canadian Export Antitrust Litigation, 522 F.3d 6 (1st Cir.

2008), for the proposition that a market involving

individualized negotiations is inherently incompatible with

common impact. This reliance is misplaced.26In New Motor

Vehicles, plaintiffs raised a “novel and complex” theory of

how consumers were injured by defendants’ alleged

horizontal conspiracy to discourage imports of lower-cost

cars from Canada into the United States. Id. at 27. Plaintiffs’

theory proceeded in two steps: (1) “but for the defendants’

illegal stifling of competition,” manufacturers would have set

lower prices to compete with Canadian imports; and

(2) because the manufacturers did not do so, consumers paid

higher retail prices. Id. The First Circuit rejected this theory

26 As a threshold matter, the First Circuit held in New Motor Vehicles

that the district court lacked federal jurisdiction over the plaintiffs’ claims,

but went on to provide its thoughts on certification of the class in the event

the district court exercised its discretion to exert supplemental jurisdiction

over the state damages claims. 522 F.3d at 17.
50 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

because plaintiffs failed to demonstrate they had an approach

for proving either step. For the first step, plaintiffs had not

shown how they would establish that but for the horizontal

conspiracy, enough lower-priced Canadian cars would flood

into the American market so as to cause manufacturers to

decrease their prices. Id. As for the second step, the

plaintiffs had not proved their damages model was capable of

showing “which consumers were impacted by the alleged

antitrust violation and which were not.” Id. at 28. In this

regard, the plaintiffs relied on an inference that “any upward

pressure on national pricing would necessarily raise the prices

actually paid by individual consumers.” Id. at 29. But the

First Circuit rejected this inference because “[t]oo many

factors play into an individual negotiation to allow an

assumption—at least without further theoretical

development—that any price increase or decrease will always

have the same magnitude of effect on the final price paid.” 

Id. at 29 (emphasis added). The court contrasted the

plaintiffs’ unsupported inference with cases allowing “a

presumption of class-wide impact in price-fixing cases when

‘the price structure in the industry is such that nationwide the

conspiratorially affected prices at the wholesale level

fluctuated within a range which, though different in different

regions, was higher in all regions than the range which would

have existed in all regions under competitive conditions.’” 

Id. (quoting In re Linerboard Antitrust Litig., 305 F.3d 145,

151 (3d Cir. 2002)). Despite rejecting the plaintiffs’ theory

at an early stage of the case, the court did not rule out

certification of a class but instead concluded that “more work

remained to be done in the building of plaintiffs’ damages

model and the filling out of all steps of plaintiffs’ theory of

impact.” Id.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 51

As this explanation of the case makes clear, New Motor

Vehicles’ analysis is not applicable here. First, the DPPs’

price-fixing theory is not “novel” or “complex.” Id. at 27. 

Rather than adopting a theory requiring multiple speculative

steps, the DPPs have a simple one-step theory: the Tuna

Suppliers conspired to raise tuna prices, resulting in higher

prices for all buyers. Second, while the plaintiffs in New

Motor Vehicles had not provided a thorough explanation or

developed a model showing how they would establish their

theory, id. at 29, the DPPs have already offered welldeveloped expert testimony and regression modeling

supporting common impact. The other cases relied on by the

Tuna Suppliers are equally inapposite. See, e.g., Blades v.

Monsanto Co., 400 F.3d 562, 572 (8th Cir. 2005) (affirming

denial of class certification because evidence of a conspiracy

to raise prices, without more, could not demonstrate impact

across highly localized and highly individualized markets for

hundreds of seed varieties, and the plaintiffs had not offered

a common method of showing injury); Robinson v. Tex. Auto.

Dealers Ass’n, 387 F.3d 416, 423 (5th Cir. 2004) (reversing

class certification where the plaintiffs lacked a plausible

theory of how the challenged conduct had consistently

affected purchase prices).

The Tuna Suppliers also argue that because the individual

plaintiffs pursuing their own antitrust claims showed

overcharges both above and below the overcharge indicated

by Dr. Mangum’s model, a uniform 10.28 percent overcharge

is implausible. We also reject this argument, because it

improperly conflates the question whether evidence is

capable of proving an issue on a class-wide basis with the

question whether the evidence is persuasive. A lack of

persuasiveness is not fatal at certification. See Amgen,

568 U.S. at 459–60. For purposes of determining whether
52 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

each member of the DPP class can rely on the model to prove

antitrust impact, it is irrelevant whether actual sales data

shows a specific class member was overcharged by more or

less than 10.28 percent. Rather, the question is whether each

member of the class can rely on Dr. Mangum’s model to

show antitrust impact of any amount. The district court did

not abuse its discretion in finding that each member could. 

While individualized differences among the overcharges

imposed on each purchaser may require a court to determine

damages on an individualized basis, see supra Section III.C,

such a task would not undermine the regression model’s

ability to provide evidence of common impact. Accordingly,

we reject the Tuna Suppliers’ argument that the regression

model could not sustain liability in individual proceedings. 

Rather, “each class member could have relied on [the model]

to establish liability if he or she had brought an individual

action.” See Tyson Foods, 577 U.S. at 455. We therefore

conclude that the district court did not err legally or factually

in concluding that Dr. Mangum’s pooled regression model

does not fail on any of the grounds raised by the Tuna

Suppliers.27

B

The Tuna Suppliers and the dissent next contend that the

district court erred by failing to resolve a dispute between the

parties as to whether 28 percent of the class did not suffer

27 The Tuna Suppliers do not “specifically and distinctly” raise the

argument that the district court abused its discretion in resolving

challenges to the inputs to the model which were raised below, such as

Dr. Mangum’s choice of benchmark period and use of cost indexes, so

that argument is deemed forfeited on appeal. United States v. Kama,

394 F.3d 1236, 1238 (9th Cir. 2005).
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 53

antitrust impact. Instead of resolving the dispute between the

parties’ experts, the Tuna Suppliers claim, the district court

improperly shifted the critical inquiry to the jury. In other

words, the Tuna Suppliers argue that to satisfy Rule

23(b)(3)’s predominance requirement, plaintiffs must prove

that all or nearly all class members were in fact injured by the

alleged conspiracy, i.e., suffered antitrust impact.28

In raising this argument, the Tuna Suppliers focus on

Dr. Johnson’s critique of Dr. Mangum’s model, which stated

that when he tested Dr. Mangum’s model by changing it to

evaluate the overcharge specific to each individual member

of the DPP class, the test showed that 28 percent of the DPPs

could not rely on the model to show an overcharge

attributable to the conspiracy. According to the Tuna

Suppliers, this evidence indicated that 28 percent of the DPP

class did not suffer antitrust impact. And in district court, the

Tuna Suppliers argued that “28% of a class—nearly onethird—far exceeds the de minimis number of uninjured class

members that some courts have permitted in certifying a

class.” Therefore, the Tuna Suppliers argue that the class

should not have been certified. Further, the Tuna Suppliers

argue that the existence of a large number of uninjured class

members raises a question as to whether the class has Article

III standing. The Tuna Suppliers contend that because the

class cannot be certified (and there are Article III issues) if

Dr. Johnson’s analysis is correct, the district court abused its

discretion in failing to resolve the dispute regarding whether

28 Because the Tuna Suppliers’ primary argument on appeal is that the

DPPs failed to prove class-wide antitrust impact, we understand the Tuna

Suppliers’ reference to injury as referring to antitrust impact, an element

of the class antitrust claims, not that the class members would not be able

to prove that they suffered monetary damages.
54 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Dr. Johnson’s conclusions about Dr. Mangum’s model were

correct.

We disagree. First, the Tuna Suppliers and the dissent

mischaracterize the import of Dr. Johnson’s critique. 

Dr. Johnson did not make a factual finding that 28 percent of

the DPP class or 169 class members were uninjured. Instead,

Dr. Johnson’s test was aimed at undermining confidence in

Dr. Mangum’s pooled regression model, because class

members with no or limited transactions during the

benchmark period could not rely on the model to show that

they suffered overcharges. At most, this critique supports the

more attenuated argument that Dr. Mangum’s model is

unreliable, or would be unpersuasive to a jury. But the

district court considered and resolved this methodological

dispute between the experts in favor of Dr. Mangum by

crediting his rebuttal that even class members with limited

transactions during the class period can rely on the pooled

regression model as evidence of impact on similarly situated

class members. In other words, the district court determined

that Dr. Mangum’s pooled regression model was capable of

showing that the DPP class members suffered antitrust impact

on a class-wide basis, notwithstanding Dr.Johnson’s critique. 

This was all that was necessary at the certification stage. The

DPP class did not have to “first establish that it will win the

fray” in order to gain certification under Rule 23(b)(3). 

Amgen, 568 U.S. at 460. Nor is this a case such as Ellis, in

which the court had to resolve a dispute regarding an issue of

historical fact in order to determine whether the challenged

discriminatory conduct could affect a class as a whole. See

657 F.3d at 983. There is no factual dispute that the Tuna

Suppliers engaged in a price-fixing scheme affecting the

entire packaged tuna industry nation-wide.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 55

The district court’s conclusion that the Tuna Suppliers

could present Dr. Johnson’s critique at trial did not

improperly shift the burden of determining whether the Rule

23(b)(3) prerequisites were met to the jury.29See Amgen,

568 U.S. at 459–60, 466. The district court fulfilled its

obligation to resolve the disputes raised by the parties in

order to satisfy itself that the evidence proves the

prerequisites for Rule 23(b)(3), which is that the evidence

was capable of showing that the DPPs suffered antitrust

impact on a class-wide basis. “Reasonable minds may differ

as to whether the [overcharge Dr. Mangum] calculated is

probative” as to all purchasers in the class, but that is a

question of persuasiveness for the jury once the evidence is

sufficient to satisfy Rule 23. See Tyson Foods, 577 U.S.

at 459.

Neither Dr. Mangum’s pooled regression model nor

Dr. Johnson’s critique required individualized inquiries into

the class members’ injuries. If the jury found that

Dr. Mangum’s model was reliable, then the DPPs would have

succeeded in showing antitrust impact on a class-wide basis,

an element of their antitrust claim. On the other hand, if the

jury were persuaded by Dr. Johnson’s critique, the jury could

conclude that the DPPs had failed to prove antitrust impact on

29 The Tuna Suppliers do not “specifically and distinctly” develop the

argument that the district court failed to resolve the parties’ dispute as to

whether the evidence generated false positives. Kama, 394 F.3d at 1238. 

In any event, as explained above, Dr. Mangum rebutted these critiques by

reference to the umbrella effect, and by claiming that Dr. Johnson’s

analysis was itself flawed because Dr. Johnson thought DPP class

members had purchased non-defendant tuna, when they actually

purchased tuna supplied by defendants. The district court did not abuse

its discretion in resolving this issue by crediting Dr. Mangum’s rebuttal.
56 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

a class-wide basis.30In neither case would the litigation raise

individualized questions regarding which members of the

DPP class had suffered an injury. Although such issues

would have to be addressed at the damages stage, the

dissent’s argument that the district court here erred by failing

to determine whether questions of individualized damages

predominate, Dissent at 74, misses the mark. As noted above,

the Tuna Suppliers have not argued that the complexity of

damages calculations would defeat predominance here, and

as previously explained, there is no per se rule that a district

court is precluded from certifying a class if plaintiffs may

have to prove individualized damages at trial.31

We need not consider the Tuna Suppliers’ argument that

the possible presence of a large number of uninjured class

members raises an Article III issue, because the Tuna

Purchasers have demonstrated that all class members have

30 Although Dr. Johnson argued that Dr. Mangum’s pooled regression

model was unreliable and so could not sustain a jury finding of antitrust

injury to the entire DPP class, the evidence adduced at trial may

nevertheless sustain a jury finding of antitrust injury to all or part of the

class.

31 In any event, Dr. Mangum’s proposal for calculating damages is a

straightforward process of applying the class-wide overcharge to the Tuna

Purchasers’ net sales records. See supra n.19. That proposal does not

give rise to a concern about individualized mini-trials to determine each

class member’s damage award. “That the defendant might attempt to pick

off the occasional class member here or there through individualized

rebuttal does not cause individual questions to predominate.” Halliburton,

573 U.S. at 276.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 57

standing here.32 A plaintiff is required to establish the

elements necessary to prove standing “with the manner and

degree of evidence required at the successive stages of the

litigation.” Lujan v. Defs. of Wildlife, 504 U.S. 555, 561

(1992). Here, the district court concluded that the DPPs’

evidence was capable of establishing antitrust impact on a

class-wide basis. Because antitrust impact—i.e., that the

Tuna Suppliers’ collusion had a common, supra-competitive

impact on a class-wide basis—is sufficient to show an injuryin-fact traceable to the defendants and redressable by a

favorable ruling, the Tuna Purchasers have adequately

demonstrated Article III standing at the class certification

stage for all class members, whether or not that was required. 

See TransUnion, 141 S.Ct. at 2208 n.4.

32 The Supreme Court expressly held open the question “whether

every class member must demonstrate standing before a court certifies a

class.” TransUnion, 141 S.Ct. at 2208 n.4 (emphasis omitted). Outside

the class action context, the Supreme Court has held that each plaintiff

must demonstrate Article III standing in order to seek additional money

damages and, therefore, a litigant must demonstrate Article III standing in

order to intervene as a matter of right. Town of Chester v. Laroe Ests.,

Inc., 137 S.Ct. 1645, 1651 (2017). But the Supreme Court has long

recognized that in cases seeking injunctive or declaratory relief, only one

plaintiff need demonstrate standing to satisfy Article III. See, e.g.,

Baggett v. Bullitt, 377 U.S. 360, 366 n.5 (1964); Rumsfeld v. F. for Acad.

& Institutional Rts., Inc., 547 U.S. 47, 52 n.2 (2006); Horne v. Flores,

557 U.S. 433, 446–47 (2009). We have likewise applied this rule where

a class sought injunctive or equitable relief. See Bates v. United Parcel

Serv., Inc., 511 F.3d 974, 985 (9th Cir. 2007) (en banc). We therefore

overrule the statement in Mazza that “no class may be certified that

contains members lacking Article III standing,” 666 F.3d at 594, which

does not apply when a court is certifying a class seeking injunctive or

other equitable relief. We do not overrule Mazza as to any other holding

which remain good law.
58 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

Accordingly, we affirmthe district court’s certification of

the DPP class.

V

We next turn to the Tuna Suppliers’ arguments that the

district court abused its discretion in determining that the

evidence presented by the CFPs and EPPs was capable of

proving the element of antitrust impact under California’s

Cartwright Act, thus satisfying the prerequisites of Rule

23(b)(3).

A

The CFP subclass includes individuals and commercial

entities who purchased bulk sized packaged tuna (packages

of 40 ounces or more) from six companies (direct purchasers)

which had purchased the tuna from the Tuna Suppliers. The

CFPs’ theory of antitrust impact proceeds in two steps. First,

the CFPs claim that the Tuna Suppliers’ conspiracy resulted

in the direct purchasers paying an overcharge. Second, the

CFPs claim that the overcharge was passed on from the direct

purchasers to the CFPs.

The CFPs supported this theory with the expert testimony

and report of economist Dr. Michael Williams, who

employed a methodology substantially similar to that

employed by Dr. Mangum. Dr. Williams first conducted a

regression analysis to determine the overcharge the CFPs’

suppliers (i.e., the six direct purchasers) incurred because of

the Tuna Suppliers’ collusion. Like Dr. Mangum’s analysis,

Dr. Williams’s regression analysis controlled for the effect of

other variables that affected price in order to isolate the effect

of the Tuna Suppliers’ collusion. Dr. Williams concluded
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 59

that COSI overcharged the CFPs’ direct purchasers by

16.6 percent, StarKist by 18.2 percent, and Bumble Bee by

15.3 percent.

Next, Dr. Williams performed a separate regression

analysis to determine if those overcharges passed through to

the CFPs, and determined that the direct purchasers passed

through 92 to 113 percent of their overcharge to the CFPs. 

Dr. Williams then performed two tests to verify that his

estimates applied class-wide, both of which confirmed his

theory.

To rebut Dr. Williams’s analysis, the Tuna Suppliers

relied on a critique by economist Dr. Linda Haider. 

Dr. Haider asserted that Dr. Williams erroneously assumed

that all CFPs paid a common overcharge and that the same

overcharge was passed through to the individual CFPs. 

Dr. Haider also contended that some of the CFP class

members, such as food preparers and distributors, were not

impacted because they could have passed through their

overcharges to other purchasers downstream. Finally,

Dr. Haider claimed that Dr. Williams’s model was unreliable

because it failed to account for non-defendant tuna purchased

by the CFPs’ direct purchasers.

The district court reviewed Dr. Williams’s report and

testimony as well as Dr. Haider’s critiques, and after

resolving the parties’ disputes, concluded that Dr. Williams’s

methodology was valid and capable of resolving the antitrust

impact issue in a single stroke, even though the Tuna

Suppliers could raise the same critiques at trial to persuade

the jury.
60 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

On appeal, the Tuna Suppliers argue that the district court

abused its discretion in concluding that Dr. Williams’s

methodology satisfied Rule 23(b)(3)’s requirement of

common proof of antitrust impact, because Dr. Williams

erred in assuming that all direct purchasers were overcharged

by the same percentage and that each class member was

subject to the same pass-through rate. We disagree. As

explained in Section IV, supra, a district court does not abuse

its discretion in concluding that a regression model such as

the one used by Dr. Williams may be capable of showing

class-wide antitrust impact, provided that the district court

considers factors that may undercut the model’s reliability

(such as unsupported assumptions, erroneous inputs, or

nonsensical outputs such as false positives) and resolves

disputes raised by the parties. The district court did so in this

case, and therefore did not abuse its discretion in concluding

that Dr. Williams’s methodology was reliable and capable of

showing class-wide impact.

We also reject the Tuna Suppliers’ argument based on

Dr. Haider’s contention that some CFP class members may

have passed on their overcharges to downstream purchasers. 

Dr. Haider claimed that the CFPs’ ability to prove common

impact was problematic because the impact of overcharges on

class members who passed on their overcharges would be

different from the impact on members who did not pass on

such overcharges. The district court did not abuse its

discretion in rejecting this argument on the ground that the

Tuna Suppliers had not shown that determining whether or

not those class members had passed overcharges down the

distribution chain would overwhelm the common issues and

require an individualized analysis. Therefore, the district

court could reasonably conclude that the common question of
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 61

antitrust impact predominated over individualized questions

concerning a passed-on overcharge.

B

The EPP subclass contains individual consumers who

purchased the Tuna Suppliers’ products for personal

consumption. Thus, like the CFPs, the EPPs are indirect

purchasers whose theory of antitrust impact depends on two

separate overcharges: first, an overcharge by the Tuna

Suppliers to the direct purchasers (i.e., retail stores), and then

an overcharge passed on to the EPPs. To carry their burden

of showing they could establish class-wide overcharges

through common proof, the EPPs offered the testimony of

economist Dr. David Sunding, who employed a methodology

substantially similar to that employed by Dr. Mangum and

Dr. Williams.

Like Drs. Mangum and Williams, Dr. Sunding first

conducted a regression analysis to isolate the impact of the

collusion on the direct purchasers, which he concluded was

an 8.1 percent overcharge from COSI, 4.5 percent from

StarKist, and 9.4 percent from Bumble Bee. He then

determined that the overcharges passed through to the EPP

class members ranged from 65.3 to 135 percent with an

estimated pass-through rate of 100 percent for the entire

class. Dr. Sunding provided qualitative, quantitative and

anecdotal evidence to support his assumption of a pass

through rate for the entire class, including an examination of

retail scanner data and the Tuna Suppliers’ internal records.

Dr. Haider critiqued Dr. Sunding’s methodology and

findings on many of the same grounds as she criticized

Dr. Williams’s model and conclusions. She also made the
62 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

additional criticisms that Dr. Sunding’s methodology

produced absurd results because it showed prices that made

no economic sense, and that his model ignored, and therefore

failed to control for, important factors like loss-leader and

focal point pricing. The district court analyzed the evidence

and the experts’ disputes, and concluded that Dr. Sunding’s

report and testimony were capable of showing antitrust

impact common to the class, for the same reasons explained

in the court’s analysis of Dr. Mangum’s and Dr. Williams’s

models. The district court determined that Dr. Haider’s

additional critiques were based either on a misreading of

Dr. Sunding’s report, or her own miscalculations.

On appeal, the Tuna Suppliers argue only that

Dr. Sunding’s model and testimony was not capable of

proving common impact for all class members because of its

use of “averaging assumptions.” This argument fails for the

reasons explained above. See supra Section IV.A. Thus, the

district court properly considered and rejected Dr. Haider’s

arguments, and determined that Dr. Sunding’s methodology

was capable of proving antitrust impact on a class-wide basis. 

That is enough to satisfy Rule 23(b)(3).

VI

In a complex market such as the one at issue here, where

different purchasers with different bargaining power

purchased a range of products at different prices from

different suppliers, commentators have raised reasonable

questions whether statistical models are capable of resolving

the issue of antitrust impact with common proof. See, e.g.,

Michelle M. Burtis & Darwin V. Neher, Correlation and

Regression Analysis in Antitrust Class Certification,

77 Antitrust L.J. 495, 518 (2011). But such statistical models
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 63

and other evidence have been accepted as probative in a range

of litigation contexts, and the Supreme Court has made clear

that the permissibility of statistical evidence “turns not on the

form a proceeding takes—be it a class or individual

action—but on the degree to which the evidence is reliable in

proving or disproving the elements of the relevant cause of

action.” Tyson Foods, 577 U.S. at 455. Here the district

court did not abuse its discretion in rigorously analyzing such

statistical evidence, determining that it was not flawed in a

manner that would make it incapable of providing class-wide

proof, see supra Section III.C, concluding that the evidence

was sufficient to sustain a jury verdict on the question of

antitrust impact for the entire class, and preserving the

defendants’ ability to challenge the persuasiveness of such

evidence at trial. We therefore affirm the district court’s

decision to certify the Tuna Purchasers’ three subclasses

under Rule 23(b)(3). Nevertheless, the Tuna Suppliers will

have the opportunity to convince a jury that not all class

members were overcharged due to their collusion.

AFFIRMED.

LEE, Circuit Judge, with whomKLEINFELD, Circuit Judge,

joins, dissenting:

Over the past two decades, plaintiffs have notched over

$103 billion in settlements from securities class actions

alone.1If we include other types of class actions—wage and

1

See Securities Class Action Settlements—2019 Review and

Analysis, Harvard Law School Forumon Corporate Governance, available

at https://corpgov.law.harvard.edu/2020/03/11/securities-class-action-
64 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

hour, consumer lawsuits, antitrust disputes, and many

others—that settlement amount almost certainly swells up by

tens of billions of dollars more. These settlement sums are

staggering because class action cases rarely go to trial. If

trials these days are rare, class action trials are almost

extinct.2 And it is no wonder why class actions settle so

often: If a court certifies a class, the potential liability at trial

becomes enormous, maybe even catastrophic, forcing

companies to settle even if they have meritorious defenses.

That is why the Supreme Court has urged lower courts to

“rigorous[ly]” scrutinize whether plaintiffs have met class

certification requirements. See Wal-Mart Stores, Inc. v.

Dukes, 564 U.S. 338, 351 (2011). The majority opinion,

however, allows the district court to certify a class, even

though potentially about one out of three class members

suffered no injury. But if defendants’ econometrician expert

is correct that almost a third of the class members may not

have suffered injury, plaintiffs have not shown the

predominance of common issues under Rule 23(b).

The district court acknowledged the dueling experts’

differing opinions on this crucial question but held that it

would leave that issue for another day—at trial—because it

involves a merits issue that a jury should decide. See In re

Packaged Seafood Prods. Antitrust Litig., 332 F.R.D. 308,

settlements-2019-review-and-analysis/ (last visited Oct. 21, 2021).

2

See, e.g., Securities Class Action Filings, 2020 Year in Review,

Cornerstone Research, at 18, available at https://www.cornerstone.com/

Publications/Reports/Securities-Class-Action-Filings-2020-Year-inReview (last visited Oct. 21, 2021) (noting only 11 securities class action

cases tried to verdict in the past quarter century and only one tried since

2014).
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 65

325–28 (S.D. Cal. 2019). But as a practical matter, that day

will likely never come to pass because class action cases

almost always settle once a court certifies a class. A district

court thus must serve as a gatekeeper to resolve key issues

implicating Rule 23 requirements—including whether too

many putative class members suffered no injury—at the class

certification stage. See Med. & Chiropractic Clinic, Inc. v.

Oppenheim, 981 F.3d 983, 992 (11th Cir. 2020) (“Rule 23

makes clear that the district court in which a class action is

filed operates as a gatekeeper”).

Punting this key question until later amounts to handing

victory to plaintiffs because this case will likely settle without

the court ever deciding that issue. The refusal to address this

key dispute now is akin to the NFL declining to review a

critical and close call fumble during the waning minutes of

the game unless and until the game reaches overtime (which,

of course, will likely never occur if it does not decide the

disputed call). Such a practice is neither fair nor true to the

rule.

I thus respectfully dissent.

* * * * *

The U.S. Department of Justice’s investigation revealed

that the three largest domestic producers of packaged tuna

colluded to try to inflate the prices of their products. This

class action lawsuit soon followed the criminal indictment. 

Among the plaintiffs include the direct purchasers of the tuna

products, ranging from multibillion dollar chain retailers to

small mom-and-pop stores. Not surprisingly, some plaintiffs

(such as Walmart) wield substantial negotiating leverage:

They can demand lower prices or extract additional
66 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

promotional credits or rebates that defray the offered price. 

In contrast, an owner of a bodega likely cannot demand even

an audience with the tuna producers, let alone ask for lower

prices or more promotional credits.

Despite the varying negotiating power among the

plaintiffs, their expert, Dr. Russell Mangum III, concluded

that the tuna producers overcharged the direct purchasers by

an average of 10.28%. He also suggested that about 5.5% of

the class may not have suffered an injury because of this

price-fixing. In contrast, the defendants’ expert, Dr. John

Johnson, offered an analysis showing that potentially about

28% of the class members suffered no injury.

Faced with this gaping difference between the two

experts’ conclusions, the district court acknowledged that

Dr. Johnson’s “criticisms are serious.” In re Packaged

Seafood, 332 F.R.D. at 328. But it held that this question

should be left for trial because Dr. Mangum’s method was

reliable under Daubert and “capable of showing” class-wide

impact. Id. The majority agrees with the district court, ruling

that a class can be certified—even if potentially one out of

three members suffered no injury—because Plaintiffs’ expert

offered a method “capable” of measuring class-wide impact

and the district court can winnow out those uninjured

members later at trial. But the majority opinion conflicts with

Rule 23’s text, common sense, and precedent from other

circuits.
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 67

I. The district court did not “rigorously” scrutinize the

dueling experts’ opinions about uninjured class

members.

While around 10,000 class action lawsuits are filed

annually3, class actions are “an exception to the usual rule

that litigation is conducted by and on behalf of the individual

named parties only.” Comcast Corp. v. Behrend, 569 U.S.

27, 33 (2013) (quoting Califano v. Yamasaki, 442 U.S. 682,

700–01 (1979)). Rule 23 thus establishes stringent

requirements for certifying a class.

Among the Rule 23 requirements, the plaintiff must show

that “questions of law or fact common to class members

predominate over any questions affecting only individual

members.” Fed. R. Civ. 23(b)(3). The word “common”

means “belonging to or shared . . . by all members of a

group,” while “predominate” means “to hold advantage in

numbers or quantity.”4 Rule 23(b)(3) thus requires that

questions of law or fact be shared by all or substantially all

members of the class.

The Supreme Court has also reminded us that Rule 23

does not establish a “mere pleading standard.” Wal-Mart,

564 U.S. at 350. Rather, plaintiffs must prove by a

preponderance of the evidence that they have met the Rule 23

requirements. See id.; Maj. Op. at 22–23. Rule 23 imposes

3 Class Actions 2021, Lexology, Jonathan D. Polkes and David J.

Lender, eds., at 91 (2021).

4

“Common” and “predominance,” Merriam-Webster Dictionary,

available at www.merriam-webster.com/dictionary (last checked on Oct.

21, 2021).
68 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

a requirement on the trial court, too. A trial court can certify

a class only after engaging in a “rigorous analysis” and

determining that the plaintiff has satisfied Rule 23. WalMart, 564 U.S. at 351. And in conducting that “rigorous

analysis,” trial courts “[f]requently” must assess “the merits

of the plaintiff’s underlying claim” because the issues are

often intertwined. Id.

Rule 23’s “rigorous analysis” is different from “reliable”

or “relevant.” Ellis v. Costco Wholesale Corp., 657 F.3d 970,

982–84 (9th Cir. 2011). A trial court must do more than just

consider one side’s expert opinion as “reliable” and then kick

the can down the road until trial. Rather, it must dig into the

weeds and decide the battle of dueling experts if their dispute

implicates Rule 23 requirements.

Here, the two experts’ contentions centered on

Rule 23(b)(3)’s predominance requirement—whether it has

been met if the defendants’ expert concludes that potentially

a significant number of putative class members were

uninjured. Plaintiffs’ expert argued that only about one out

of twenty class members likely did not suffer an injury, while

defendants’ expert maintained it was potentially more than

one out of four. The district court held that the plaintiffs’

expert’s opinion passed muster under Daubert but admitted

that the defendants’ expert offered “serious” criticism, too. 

The district court admirably analyzed this difficult issue but

ultimately did not resolve it, ruling that a jury should decide

it at trial.

Despite the detailed analysis of the district court, I believe

it abused its discretion in committing the same error that we

cautioned against in Costco. There, the two dueling experts

offered contrasting opinions on whether Costco’s alleged
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 69

discrimination was regional or nationwide, which touched

upon Rule 23(a)’s commonality requirement (i.e., whether all

the putative class members nationwide suffered

discrimination). The trial court held the plaintiffs’ expert was

reliable under Daubert, and declined to decide which experts’

opinion should prevail at the class certification stage. It then

certified a class and ruled that this “battle of the experts”

issue could be decided at trial because Costco’s criticisms of

the expert report “attack the weight of the evidence and not

its admissibility.” Id. at 982 (quoting district court opinion).

But because that dispute implicated Rule 23(a)’s

commonality requirement, we reversed the district court’s

certification order and directed it to address it at the class

certification stage. As we put it, the trial court “confused” the

Daubertstandard’s “reliable” requirement with the “rigorous

analysis” standard for Rule 23. Id. at 982 (“Instead of

judging the persuasiveness of the evidence presented, the

district court seemed to end its analysis of the plaintiffs'

evidence after determining such evidence was merely

admissible.”). Rather than “examining the merits [of the

dispute between experts] to decide this issue,” the trial court

“merely concluded that, because both Plaintiffs’ and Costco’s

evidence was admissible, a finding of commonality was

appropriate.” Id. at 984. That was error.

And that is exactly what happened here. The district

court found plaintiffs’ expert to be reliable under Daubert,

but it also conceded that the defendants’ expert offered a

“serious” critique of plaintiffs’ expert opinion. The district

court ultimately held that resolving this “battle of the experts”

was a merits issue. But the dispute over the number of

uninjured class members overlaps with Rule 23(b)(3)’s

predominance requirement as well as Rule 23(a)’s lower
70 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

threshold commonality requirement. Simply put, a plaintiff

cannot prove that common issues predominate if one out of

three putative class members suffered no harm. Cf. Mazza v.

Am. Honda Motor Co., Inc., 666 F.3d 581, 596 (9th Cir.

2012) (“[T]he relevant class must be defined in such a way as

to include only members who were [harmed by being]

exposed to advertising that is alleged to be materially

misleading.”). If a large number of class members “in fact

suffered no injury,” identifying those class members “will

predominate.” In re Asacol Antitrust Litig., 907 F.3d 42,

53–54 (1st Cir. 2018). Thus, the district court had to

“examin[e] the merits” of this dispute between the experts,

and not “merely conclude[] that” both expert reports are

reliable and admissible. Costco, 657 F.3d at 984.

The majority holds that Dr. Mangum’s estimate of a

10.2% “average” price inflation meets Rule 23’s requirements

because it shows a method “capable” of showing common

antitrust impact. The majority appears to distinguish between

(i) cases in which the class members “logically” could not

have been harmed (because, for example, they were never

exposed to the misleading advertisement) or there is

insufficient evidence to support commonality, and (ii) cases

like this one in which an expert holds that many class

members in reality may not have suffered any harm, even if

they theoretically could have. Maj. Op. 26, n.9. In the

former scenario, the majority says that a class cannot be

certified because logically there cannot be commonality

under Rule 23; in the latter case, the majority appears to argue

that it is a merits issue because a jury will need to assess the

persuasiveness of the expert’s opinion.

I believe that creates a false distinction. Nothing in our

decision in Costco or the Supreme Court’s opinion in
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 71

Wal-mart creates such a difference. If the evidence presented

implicates Rule 23—as it does here—then the district court

must decide whether the plaintiffs have “prove[n] that there

are in fact . . . common questions of law or fact,” even if it

means assessing the persuasiveness of the expert opinions. 

Wal-mart, 564 U.S. at 350–51 (emphasis in original). In

Costco, we chastised the district court for not “judging the

persuasiveness of the evidence presented” and “end[ing] its

analysis of the plaintiffs' evidence after determining such

evidence was merely admissible.” 657 F.3d at 982. If we

had to refrain from deciding the persuasiveness of an expert

opinion used to show commonality, a plaintiff could prevail

on class certification by merely offering a well-written and

plausible expert opinion. See West v. Prudential Sec., Inc.,

282 F.3d 935, 938 (7th Cir. 2002) (failure to resolve dueling

experts “amounts to a delegation of judicial power to the

plaintiffs, who can obtain class certification just by hiring a

competent expert”).

Admittedly, resolving a battle of dueling experts over

highly technical issues may seem like a difficult job for a

court. But that tough task is likely even more difficult and

daunting for jurors. In the end, a “district judge may not duck

hard questions by observing that each side has some support

. . . Tough questions must be faced and squarely decided, if

necessary by holding evidentiary hearings and choosing

between competing perspectives.” Id. After reviewing the

evidence, a district court must make findings of fact

necessary for determining whether Rule 23’s requirements

have been met.

And here, the expert opinion offered by Plaintiffs to show

commonality (though admissible) is not persuasive. The

majority contends that the expert’s model is capable of
72 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

measuring class-wide impact through an “averaging

assumption” of 10.2% price inflation from the price-fixing

conspiracy. Put another way, the model assumes that almost

all class members suffered an injury because the price-fixing

would elevate the list price of tuna for everyone, even if

individual class members ultimately paid different prices for

the tuna. But the expert’s assumption flies against common

sense and empirical evidence. Powerful retailers (like

Walmart) are not passive or ill-informed consumers; they will

not sit still when faced with a price increase. They will

fiercely negotiate the list price down, or more likely, demand

promotional credits or rebates that offset any price increase. 

See R. Pandey, et al., Factors Influencing Organization

Success: A Case Study of Walmart, International Journal of

Tourism & Hospitality in Asia Pasific, Vol. 4, No. 2, June

2021. See also Gary Rivlin, Rigged: Supermarket Shelves for

Sale, Center for Science in the Public Interest, September

2016, available at cspinet.org/Rigged (last visited January 4,

2021).

Major retailers wield significant power over

manufacturing and food companies because they represent

the major channel to distribute the food products. If a major

retail chain refuses to carry a company’s product after a

pricing dispute, it can significantly affect that company’s

bottom line. As one case study put it, “Walmart has huge

bargaining power since . . . it is one of the largest distributors

for manufacturing [sic]. For instance, 17% of the total sales

of P&G and 38.7% of the total sales of CCA Industries rely

on Walmart stores. Without Walmart, these businesses would

be unable to operate.” Pandey, supra page 10, at 120.

Large retailers can also extract rebate or promotional

concessions from the companies by threatening to place their
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 73

products at the bottom of the shelves or less-visited aisles

where consumers are less likely to notice them. All told,

large retailers use this power to “collect more than $50 billion

a year in trade fees and discounts from food and beverage

companies.” Rivlin, supra page 10, at ii. And “[f]ood

manufacturers pay these fees . . . because they have no

choice. The stores are the gatekeepers.” Id. at 21.

None of this is to say that Wal-Mart and other retailers

achieved those price discounts and promotional credits or

rebates here. We simply do not know because Plaintiffs’

expert did not adequately consider it.5 The only way we can

find out if Wal-Mart and other major retailers suffered any

injury (and if so, how much) would be if we conducted highly

individualized analyses of each class member. But that

would defeat the commonality requirement under Rule 23.

The majority seemingly waves away this difference in

negotiating power between the class members by relying on

our oft-quoted language that the “need for individualized

findings as to amount of damages does not defeat class

certification.” Maj. Op. 30 (citing Vaquero v. Ashley

Furniture Indus., Inc., 824 F.3d 1150, 1155 (9th Cir. 2016);

Pulaski & Middleman, LLC v. Google, Inc., 802 F.3d 979,

988 (9th Cir. 2015)).

5 The majority cites the deposition testimony of Plaintiffs’ expert to

argue that he considered promotional credits and rebates. Maj. Op. 36,

n.16. But the expert added the caveat that he did so only in instances that

he “could reliably” calculate the data. He then conceded that he did not

include “discount or promotional information” with much of the data but

said that “I have done all that I could.” He ultimately concluded that he

could measure damages by relying on the average 10.2% “overcharge”

analysis in his expert report.
74 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

I believe our court has misconstrued that often-quoted

language to create a sweeping rule that gives a free pass to the

intractable problem of highly individualized damages

analyses. And such a rule also conflicts with the Supreme

Court’s holding that a class action must be capable of being

resolved in “one stroke.” Wal-mart, 564 U.S. at 350; see

also Comcast, 569 U.S. at 35 (requiring a “rigorous analysis”

to confirm that the damages model is “consistent with its

liability case”).

We first stated that the “amount of damages is invariably

an individual question and does not defeat class action

treatment” in Blackie v. Barrack, 524 F.2d 891, 905 (9th Cir.

1975). That was a securities fraud class action, and we

recognized that “computing individual damages will be

virtually a mechanical task” because “the amount of price

inflation during the period can be charted.” Id. (emphasis

added). Put another way, damages can be easily calculated

because it is a plug-and-play exercise: Look at the number of

shares bought by each shareholder and the price of the share

that day, and compare it to the price inflation caused by the

misrepresentation. While each class member may have

individualized damages, the damages can be easily calculated

for the entire class in “one stroke.” See Wal-mart, 564 U.S.

at 350.

Since Barrack, we have applied that concept mostly in

employment and wage-and-hour cases. See, e.g., Vaquero,

824 F.3d at 1152 (suing for payment for unpaid hours on nonsales work); Levya v. Medline Indus. Inc., 716 F.3d 510, 514

(9th Cir. 2013) (class action based on wage and hour claims

inwhich defendant’s “computerizedpayroll and time-keeping

database would enable the court to accurately calculate

damages”). Wage-and-hour cases present another mechanical
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 75

application scenario: a class administrator can easily look at

the employer’s payroll records and calculate the number of

hours or wages that each employee was underpaid. At times,

however, we have quoted that language without determining

whether damages could be calculated mechanically or if the

court would have to engage in individualized mini-trials for

damages. See, e.g., Yokoyama v. Midland Nat. Life Ins. Co.,

594 F.3d 1087, 1094 (9th Cir. 2010) (stating that

individualized damages do not defeat class certification in

case involving misleading statements in annuities

promotional materials).

But here, it will not be a “mechanical task” to calculate

the damages for each class member. Blackie, 524 F.2d

at 905. The district court will need to conduct individualized

mini-trials to determine whether each class member suffered

an injury, and if so, what the damages are for each member. 

That would upend Rule 23’s commonality requirement. The

majority opinion notes that commonality may still be met,

even if a defendant “might attempt to pick off the occasional

class member here or there.” Maj. Op. 56, n. 31 (citing

Halliburton Co. v. Erica P. John Fund, Inc., 573 U.S. 258,

276 (2014)). But our case does not involve a “pick off” of a

few uninjured class members, but rather a massive grab bag

of class members—perhaps almost a third of the class—who

may not have suffered any harm. The district court thus will

have to engage in individualized mini-trials to figure out who

suffered an injury.

Finally, the majority suggests that an oversized class with

unharmed class members does not pose a practical problem

if a method can separate the uninjured from the injured at

trial. No harm, no foul, the majority implies. But that cannot

be so if a large number of class members (certainly, a third)
76 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

suffered no injuries. Suppose that 80% of the putative class

members suffered no harm. Could a district court still certify

a class just because it could later winnow out the 80% who

were uninjured? Would Rule 23(b)’s predominance of

common issues be met even if only 20% of the putative

members belong in the class? By definition, a class with 80%

uninjured members cannot present a predominance of

common issues because they have nothing in common with

the remaining sliver of injured members.

If we allow a court to certify a class in which a large

number of putative class members have suffered no injury,

we will allow plaintiffs to weaponize Rule 23 to impose an in

terrorem effect on defendants. The “[c]ertification of the

class is often, if not usually, the prelude to a substantial

settlement by the defendant because the costs and risks of

litigating further are so high.” Amgen Inc. v. Conn. Ret. Plans

& Tr. Funds, 568 U.S. 455, 485 (2013) (Scalia, J.,

dissenting). Indeed, “when damages allegedly owed to tens

of thousands of potential claimants are aggregated and

decided at once, the risk of an error will often become

unacceptable. Faced with even a small chance of devastating

loss, defendants will be pressured into settling questionable

claims.” AT&T Mobility LLC v. Concepcion, 563 U.S. 333,

350 (2011).

So if a court certifies a class with many uninjured class

members, it dramatically expands the potential exposure and

artificially jacks up the stakes. It matters little that the

uninjured class members can be separated at trial because

with “the stakes so large . . . settlement becomes almost

inevitable—and at a price that reflects the risk of a

catastrophic judgment as much as, if not more than, the actual

merit of the claims.” In re Bridgestone/Firestone, Inc.,
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 77

288 F.3d 1012, 1016 (7th Cir. 2002). The opportunity at trial

to jettison uninjured members from the certified class is a

phantom solution because defendants will have little choice

but to settle before then.

II. The majority’s rejection of a de minimis rule creates

a circuit split. 

I believe the majority also errs in rejecting a de minimis

rule. To be sure, a plaintiff need not show that every single

putative class member has suffered an injury. But the number

of uninjured class members should be de minimis—based on

Rule 23’s language, common sense, and precedent fromother

circuits.

First, as noted above, the words “common” and

“predominate” in Rule 23(b)(3) suggest that the class should

include only (or mostly only) people who have suffered an

injury. If one-third—or half or two-thirds—of the class

members suffered no injury, it follows that “common” issues

would not “predominate,” as required under the text of Rule

23, because those uninjured class members have little in

common with those who have been harmed. In short, Rule 23

allows a de minimis number of uninjured members but no

more.

Second, allowing more than a de minimis number of

uninjured class members tilts the playing field in favor of

plaintiffs. By expressly rejecting a de minimis rule, the

majority’s opinion will invite plaintiffs to concoct oversized

classes stuffed with uninjured class members—with little fear

of having their class certification bids being denied for lack

of “predominance” or “commonality.” And in creating these

grossly oversized classes, plaintiffs will inflate the potential
78 OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS

liability (and ratchet up the attorney’s fees based in part on

that amount) to extract a settlement, even if the merits of their

claims are questionable.

Finally, the majority opinion needlessly creates a split

with other circuits that have endorsed a de minimis rule. The

D.C. Circuit, for example, suggested that “5% to 6%

constitutes the outer limits of a de minimis number.” In re

Rail Freight Fuel Surcharge Antitrust Litig., 934 F.3d 619,

624–25 (D.C. Cir. 2019) (cleaned up). The district court had

found that the class of 16,065 members (12.7% of whom

were uninjured) failed to meet the predominance requirement

because more than a “de minimis” number were uninjured. 

Id. at 623–24. The D.C. Circuit on appeal affirmed, ruling

that the plaintiffs’ model “even if sufficiently reliable, does

not prove classwide injury.” Id. at 623. Put another way,

“even assuming the model can reliably show injury and

causation for 87.3 percent of the class, that still leaves the

plaintiffs with no common proof of those essential elements

of liability for the remaining 12.7 percent.” Id. at 623–24

Likewise, the First Circuit suggested that “around 10%”

of uninjured class members marks the de minimis border. See

In re Asacol, 907 F.3d at 47, 51–58. The First Circuit was

perhaps willing to look past “a very small absolute number of

class members” who have suffered no injury because they

“might be picked off in a manageable, individualized process

at or before trial.” Id. at 53. But if “there are apparently

thousands who in fact suffered no injury . . . [t]he need to

identify those individuals will predominate.” Id. at 53–54.

* * * * *
OLEAN WHOLESALE GROCERY V. BUMBLE BEE FOODS 79

While this case centers on the narrow issue of price-fixing

of canned tuna, its implications extend beyond to a wide sea

of class action cases. I fear that today’s decision will unleash

a tidal wave of monstrously oversized classes designed to

pressure and extract settlements.

I respectfully dissent.