Pit Row, Inc. v. Costco Wholesale Corporation

In the

United States Court of Appeals

For the Seventh Circuit

____________________

No. 23-1800

PIT ROW, INC., et al.,

Plaintiffs-Appellants,

v.

COSTCO WHOLESALE CORPORATION,

Defendant-Appellee.

____________________

Appeal from the United States District Court for the

Eastern District of Wisconsin.

No. 1:20-cv-00738 — William C. Griesbach, Judge.

____________________

ARGUED FEBRUARY 7, 2024 — DECIDED APRIL 30, 2024

____________________

Before WOOD, LEE, and PRYOR, Circuit Judges.

WOOD, Circuit Judge. The plaintiffs in this appeal, a dozen

gas stations in the Green Bay, Wisconsin, area, contend that

Costco Wholesale Corporation (“Costco”) violated a Wiscon-

sin law that prohibits selling gasoline for less than the statu-

torily defined cost. They seek an injunction that prevents

Costco from selling gasoline below that level and over half a

million dollars each in damages. Costco argues that on nearly

every date at issue it lowered its prices only to match a

2 No. 23-1800

competitor’s price, which the statute allows, and that in any

event, the plaintiffs failed to establish the causal element of

the statutory claim. The district court agreed with Costco and

awarded it summary judgment. The plaintiffs challenge that

decision, as well as an evidentiary ruling the court made ear-

lier in the proceedings. We affirm on both counts.

I

A. The Act

At the center of this appeal lies Wisconsin’s Unfair Sales

Act, Wis. Stat. § 100.30 (“the Act”), commonly known as the

“Minimum Markup Law.” Like many similar laws that were

enacted by state legislatures after the first World War, the Act

purports to mandate trade-regulation concepts similar to

those that motivated the National Industrial Recovery Act of

1933, Pub. L. No. 73-67, 48 Stat. 195, invalidated by A.L.A.

Schechter Poultry Corp. v. United States, 295 U.S. 495 (1935). See,

e.g., IOWA CODE ANN. § 551.1–555.2, 551.4–551.11; MINN. STAT.

ANN. § 325D.03; see also Robinson-Patman Act of 1936, Pub.

L. No. 74-692, 49 Stat. 1526 (codified at 15 U.S.C. § 13). Wis-

consin’s Act has been modified several times over its eighty-

some-year life, but the policy underlying the legislation has

remained the same. The first provision of the Act states its ra-

tionale: “The practice of selling certain items of merchandise

below cost in order to attract patronage is generally a form of

deceptive advertising and an unfair method of competition in

commerce.” Wis. Stat. § 100.30(1).

Motor-vehicle fuel (that is, gasoline) is one of the items of

merchandise covered by the Act. As relevant here, the law

makes loss leaders unlawful by prohibiting “[a]ny sale of any

item of merchandise … by a retailer … of motor vehicle

No. 23-1800 3

fuel … , at less than cost as defined [by the Act] with the intent

or effect of inducing the purchase of other merchandise or of

unfairly diverting trade from a competitor[.]” Id. § 100.30(3).

Formulas set forth in the statute determine the minimum law-

ful selling price in relation to the costs borne by the retailer.

See id. § 100.30(2)(am). The statutory definition of the cost of

motor-vehicle fuel is the greater of either invoice or replace-

ment cost plus a markup of 6%, or the average posted termi-

nal price plus a markup of 9.18%. See id.

§ 100.30(2)(am)(1m)(a). We refer to this as the “minimum

markup price.”

The minimum markup requirement for motor-vehicle fuel

can be enforced by district attorneys, the Wisconsin Depart-

ment of Agriculture, Trade and Consumer Protection (“the

Department”), and private parties. The Act specifically af-

fords a private right of action for “[a]ny person who is injured

or threatened with injury as a result of a sale or purchase of

motor vehicle fuel” in violation of the Act. Id. § 100.30(5m). (A

separate Wisconsin statute provides that the word “person”

under state statutory law “includes all partnerships, associa-

tions and bodies politic or corporate.” Wis. Stat. § 990.01(26);

see also Village Food & Liquor Mart v. H & S Petroleum, Inc., 647

N.W.2d 177, 183 n.7 (Wis. 2002) (applying that statutory defi-

nition of “person” to the Act).) Private individuals may seek

either injunctive relief or the greater of treble damages or

$2,000, multiplied by each day of continued violation of the

Act. See Wis. Stat. § 100.30(5m). The Act also provides that

“[e]vidence of any sale of any item of merchandise by any re-

tailer … of motor vehicle fuel … at less than [the minimum

markup price] shall be prima facie evidence of intent or effect

to … injure a competitor.” Id. § 100.30(3).

4 No. 23-1800

The Act lists nine exceptions to liability. See id. § 100.30(6);

§ 100.30(7)(c)(2). Relevant here is the seventh exception, see id.

§ 100.30(7), which the Wisconsin courts have referred to as the

“‘meeting competition’ exception,” see, e.g., Go America L.L.C.

v. Kwik Trip, Inc., 715 N.W.2d 746, 749 (Wis. Ct. App. 2006). Cf.

15 U.S.C. § 13(a) (Robinson-Patman’s “meeting competition”

defense). This exception states that the Act “shall not apply to

sales at retail … where … [t]he price of merchandise is made

in good faith to meet an existing price of a competitor and is

based on evidence in the possession of the retailer … in the

form of … [a] business record maintained by the retailer … in

the ordinary course of trade or the usual conduct of business.”

Id. § 100.30(6)(a)(7). An “existing price of a competitor” is “a

price being simultaneously offered to a buyer for merchan-

dise of like quality and quantity by a person who is a direct

competitor of the retailer … and from whom the buyer can

practicably purchase the merchandise.” Id. § 100.30(2)(cj). A

retailer that lowers the price of motor-vehicle fuel in good

faith must “submit to the [D]epartment notification of the

lower price before the close of business on the day on which

the price was lowered[.]” Id. § 100.30(7)(a). “Failure to com-

ply” with the notification requirement “creates a rebuttable

presumption that the retailer … of motor vehicle fuel … did

not lower the price to meet the existing price of a competitor.”

Id. § 100.30(7)(b).

B. The Parties

The plaintiffs are twelve corporations that each own and

operate a retail gas station in Green Bay, Wisconsin. (We refer

to them collectively as “the Green Bay Stations” unless con-

text requires otherwise.) They are open to all customers, un-

like defendant Costco. Anyone can buy gasoline from them,

No. 23-1800 5

and no one must purchase other products or services from the

convenience stores attached to the stations as a condition of

obtaining their gasoline.

Costco owns and operates members-only warehouses

across the country. Each warehouse offers a “destination”

shopping experience with a wide array of products and ser-

vices, including (at many locations) motor-vehicle fuel.

Costco’s business model is predicated on bringing high-qual-

ity products to its members at the lowest possible prices. An-

yone can become a member and thus take advantage of what

Costco offers, for a small fee; when a person becomes a mem-

ber, they must provide certain information, including an ad-

dress-of-record. In October 2013, Costco opened a warehouse

that offers motor-vehicle fuel at 2355 Costco Way, Bellevue,

Wisconsin (“Bellevue Costco”), a village near the Green Bay

metropolitan area with about 14,500 residents.

Costco uses a commercial gasoline-price reporting system

called PricePro to monitor the daily gasoline prices of 42 gas

stations that it considers to be direct competitors in the Green

Bay area. If a gas station is located within a five-mile radius of

the Bellevue Costco, then Costco automatically considers it a

direct competitor. In addition, it relies on employees and cus-

tomers of the Bellevue Costco to identify gas stations outside

that geographic area that might be direct competitors. When

a station is identified as a possible competitor, Costco’s Gas

Department turns to its “heat map” of the addresses-of-record

of Costco members who already have purchased gasoline at

the Bellevue Costco to determine whether a critical number of

them live near the potentially competing station or are likely

to pass by it on their way to the warehouse. If a sufficient

6 No. 23-1800

number of gasoline-purchasing members live near the station,

Costco will deem it a direct competitor.

The Bellevue Costco matches the gasoline prices offered

by gas stations that it considers to be direct competitors. Its

employees physically verify the two or three lowest prices of-

fered each day; they also seek visual confirmation when a sus-

piciously low price is reported. (Costco largely suspended its

daily in-person verification procedures in early 2020 to com-

ply with stay-at-home requirements in place during the

COVID-19 pandemic, but otherwise has consistently abided

by the practice.) If Costco intends to match the price of gaso-

line offered by a particular direct competitor, its Gas Depart-

ment records the reduced price in spreadsheets that collec-

tively are known as the “Comp Shop Log.”

Three of the gas stations that the Bellevue Costco identi-

fied as direct competitors are relevant to this lawsuit. The first

is a BP gas station located at 601 Lawe Street in Kaukauna,

Wisconsin (“the Kaukauna BP”), which is about 24 miles (and

a 24-minute drive) from the Bellevue Costco. Costco’s records

indicate that upwards of 500 of its members with an address-

of-record in Kaukauna made at least one purchase inside the

Bellevue Costco warehouse between October 2019 and the

end of 2020, and that 236 members with such an address-of-

record collectively purchased gas 1,644 times at that ware-

house during that period. Although the Green Bay Stations

dispute whether all of the hundreds of members Costco iden-

tified actually live within the municipal boundaries of

Kaukauna, they concede that 236 members with an address-

of-record in Kaukauna purchased gasoline from the Bellevue

Costco between those dates.

No. 23-1800 7

Costco also matches the prices of two Marathon Stations

located in the Green Bay area (“the Marathon Stations”). Alt-

hough the Marathon Stations advertise only their “street” or

“sticker” price, they allow any customer to sign up for a re-

wards program known as MakeItCount Rewards. A customer

who joins MakeItCount Rewards needs only to swipe her mem-

bership card at the pump to save five cents per gallon of gas-

oline purchased. So, for example, if the sticker price offered

by the Marathon Stations is $2.50 per gallon, a rewards mem-

ber will pay just $2.45 per gallon. The Bellevue Costco

matches the discounted price.

C. This Lawsuit

The Green Bay Stations filed this lawsuit against Costco in

Wisconsin state court on March 30, 2020. Their third amended

complaint contends that Costco violated the Act on 256 days

between October 1, 2019, and December 31, 2020, by selling

regular unleaded motor-vehicle fuel at the Bellevue Costco

below the minimum markup price. (The Green Bay Stations

initially alleged violations on 263 days, but they later with-

drew their allegations against Costco for seven of those

days—March 3, 5, and 7–12, 2020.) They assert that Costco’s

gasoline-pricing practices threatened them with lower profit

margins and a reduction in customer volume, and that it ac-

tually injured them in those ways. The Green Bay Stations

seek $2,000 each per day of violation plus interest, attorneys’

fees, and a permanent injunction to prevent Costco from sell-

ing gasoline below the minimum markup price. They also

sought (unsuccessfully) to certify a class under Wisconsin law

consisting of all retailers of regular unleaded motor-vehicle

fuel who were competitors of the Bellevue Costco and who

8 No. 23-1800

sold the fuel at or above Costco’s price during the 458-day pe-

riod set forth in the complaint.

Costco timely removed the case to the Eastern District of

Wisconsin, invoking the court’s diversity jurisdiction. See 28

U.S.C. § 1441(b); 28 U.S.C. § 1332(d). It then moved for an or-

der compelling the Green Bay Stations to disclose all gasoline-

pricing data from October 1, 2017, to March 30, 2018, and all

gasoline sales-volume data for the period from October 1,

2017, to March 30, 2019. See FED. R. CIV. P. 37. Costco argued

that this data was necessary to prove whether the Green Bay

Stations suffered an actual injury or were threatened with in-

jury within the meaning of the Act. The Green Bay Stations

opposed the motion.

In an order dated December 4, 2020, the district court

granted Costco’s motion to compel, explaining that the data

might be relevant to the question of constitutional standing.

Later, an exhibit entitled “Party Fuel Sale Trend Charts” was

produced; it contained data about daily gallons of gasoline

sold from October 1, 2017, through December 2020. Over that

time, each of the Green Bay Stations saw a downward trend

in gallons of gasoline sold per day. In separate submissions,

each plaintiff testified through a corporate representative that

its profits had declined during the period 2017 through 2020.

All of the representatives also stated that they had received

questions from customers about why their prices for gasoline

were higher than Costco’s.

Discovery continued into November 2021, when the

Green Bay Stations disclosed the expert report of a former

gasoline industry executive, Donald Strenk. He testified that

in his experience, a Costco entering a motor-vehicle-fuel mar-

ket poses a significant competitive threat to existing retailers

No. 23-1800 9

in that market. Based on his professional experience and fa-

miliarity with price-elasticity modeling, Strenk said that he

was able to conclude to “a reasonable degree of certainty” that

the Green Bay Stations were at a minimum threatened by the

Bellevue Costco’s pricing practices.

The Green Bay Stations also disclosed an expert report

from Paul Dingee, who served as the Chief of the Department

from July 1993 until January 2014. Dingee testified that when

a Costco warehouse enters a market for motor-vehicle fuel,

each existing retailer must make one of two pricing decisions:

it can either lower its prices to meet Costco’s, or it can main-

tain them and risk losing customers. And so, according to

Dingee, a retailer competing with a Costco would be pre-

sented with a Hobson’s choice: whichever route it chose, it

would suffer lost profits.

Costco then disclosed expert reports from Alan Sorenson

and John Nevin, who are professors of economics and mar-

keting, respectively. Sorenson testified that he found no sta-

tistically significant correlation between the Bellevue Costco’s

pricing practices and the Green Bay Stations’ declining sales.

The Green Bay Stations responded with a “rebuttal” report

from Strenk, who claimed that a U.K.-based firm called Kali-

brate had generated a “sophisticated simulation model” that

showed Sorenson’s conclusion was “categorically false.”

When the Green Bay Stations refused to disclose the data un-

derlying the Kalibrate analysis, Costco moved to preclude it.

The district court granted the motion, ruling that the Green

Bay Stations could rely on neither the Kalibrate analysis nor

Strenk’s summary of it.

Costco deposed Strenk on January 20, 2022. During the

deposition, Strenk informed Costco that after the Kalibrate

10 No. 23-1800

analysis had been precluded he had conducted his own sta-

tistical analysis of the Green Bay Stations’ pricing and sales

data, and that he had shared the new analysis with the Green

Bay Stations a day ago. Three weeks later, the Green Bay Sta-

tions filed a motion to supplement their expert report with

Strenk’s new analysis. Costco opposed the motion, arguing

that the proposed supplement would undermine its discov-

ery efforts in the midst of briefing on class certification and

summary judgment.

The district court held a hearing on the motion on April

18, 2022. After hearing arguments from both sides, the court

observed that the time for disclosure had long passed, and

that Costco had conducted discovery in reliance upon the ex-

pert reports the Green Bay Stations already had disclosed. Al-

lowing the Green Bay Stations to supplement their expert re-

ports at the eleventh hour would force Costco either to redo

or to change the course of discovery and would thus prejudice

its defense. For these reasons, the court denied the Green Bay

Stations’ motion to supplement.

On March 1, 2022, Costco moved for summary judgment

and for the denial of class certification. The district court

granted summary judgment to Costco and denied the Green

Bay Stations’ request to certify a class. (Its ruling on the class

aspects of the case is not before us on appeal, and so we do

not discuss it.) On the merits, the court concluded that for 238

days at issue, Costco was immune from liability pursuant to

the meeting-competition exception set forth in the Act. For the

No. 23-1800 11

remaining 18 days,1 the district court found a genuine dispute

of fact about whether Costco sold gasoline below the mini-

mum markup, and thus determined that for those days

Costco could not assert immunity under the exception. None-

theless, it further concluded that for all 256 days, Costco was

entitled to summary judgment because the Green Bay Sta-

tions had failed to show that they were injured or threatened

with injury within the meaning of the Act. The Green Bay Sta-

tions now appeal the adverse award of summary judgment

and the earlier denial of their request to supplement their ex-

pert report.

II

Before we may address the merits of this appeal, we have

“an obligation to assure ourselves” that the litigants have Ar-

ticle III standing. DaimlerChrysler Corp. v. Cuno, 547 U.S. 332,

340 (2006) (quotation omitted). To maintain an action in fed-

eral court, a plaintiff must have “(1) suffered an injury in fact,

(2) that is fairly traceable to the challenged conduct of the de-

fendant, and (3) that is likely to be redressed by a favorable

judicial decision.” Spokeo v. Robins, 578 U.S. 330, 338 (2016)

(citing Lujan v. Defs. of Wildlife, 504 U.S. 555, 560 (1992)). At the

summary judgment stage, the plaintiff “must ‘set forth’ by af-

fidavit or other evidence ‘specific facts’” to support each ele-

ment, “which for purposes of the summary judgment motion

will be taken to be true.” Lujan, 504 U.S. at 561 (quoting FED.

R. CIV. P. 56(e)).

1 Those 18 days are February 29, 2020; March 1–2, 4, and 6, 2020; April

14–15, 2020; June 26–30, 2020; September 2–3, 2020; and October 9, 11, 14,

and 17, 2020.

12 No. 23-1800

Little need be said about redressability. The Green Bay

Stations seek statutory damages and injunctive relief, both of

which are remedies that would “‘affect the behavior of the de-

fendant towards the plaintiff,’ and thus independently pro-

vide redress.” Uzuegbunam v. Preczewski, 141 S. Ct. 792, 801

(2021) (quoting Hewitt v. Helms, 482 U.S. 755, 761 (1987) (alter-

ation omitted)). We thus focus our attention on the first two

elements.

A. Injury in Fact

The Green Bay Stations do not need to show that they have

a meritorious claim to satisfy the injury-in-fact requirement.

See Owsley v. Gorbett, 960 F.3d 969, 971 (7th Cir. 2020). But they

must “show that [they] suffered an invasion of a legally pro-

tected interest that is concrete and particularized and actual

or imminent, not conjectural or hypothetical.” Spokeo, 578 U.S.

at 339 (cleaned up). In plain English, a litigant is not required

to show that it will win in order to establish standing. All it

must do to satisfy Article III is show that it “ha[s] a colorable

claim to such a right.” Aurora Loan Servs. Inc. v. Craddieth, 442

F.3d 1018, 1024 (7th Cir. 2006). “Were we to require more than

a colorable claim, we would decide the merits of the case be-

fore satisfying ourselves of standing.” Booker-El v. Superinten-

dent, Indiana State Prison, 668 F.3d 896, 900 (7th Cir. 2012).

We accept that the injury the Green Bay Stations alleged is

judicially cognizable. They claim that they suffered lost prof-

its and a decline in customer volume, and that they have a

legally protected interest in maintaining both their profits and

their customers. As the Supreme Court recently reminded us,

“monetary harms” are among the “most obvious” kinds of in-

jury in fact. TransUnion LLC v. Ramirez, 594 U.S. 413, 425

(2021); cf. Lexmark Intern., Inc. v. Static Control Components, Inc.,

No. 23-1800 13

572 U.S. 118, 126 (2014) (indicating that “lost sales and dam-

ages to … business reputation” are injuries in fact).

They also have proffered sufficient evidence of their al-

leged harms. Each of the Green Bay Stations introduced testi-

mony from a representative who claimed that their business

saw a decline in profits, as well as data showing a reduction

in their gasoline sales by volume, during the period stated in

the complaint. Given the nature of the claims that the Act au-

thorizes (i.e., actions for threatened or actual injury), that evi-

dence, taken as true, is enough to establish that the Green Bay

Stations have a colorable claim at the summary judgment

stage. See Warth v. Seldin, 422 U.S. 490, 500 (1975) (“Stand-

ing … often turns on the nature and source of the claim as-

serted.”); cf. Protect Our Parks, Inc. v. Chicago Park Dist., 971

F.3d 722, 736 (7th Cir. 2020) (noting that “when the existence

of a protected property interest is an element of the claim, de-

ciding whether the interest exists virtually always goes to the

merits rather than standing”).

B. Traceability

A similar principle informs our traceability inquiry. This

element of standing “examines the causal connection between

the assertedly unlawful conduct and the alleged injury.” Allen

v. Wright, 468 U.S. 737, 753 n.19 (1984). Significantly, “[p]rox-

imate causation is not a requirement of Article III standing,

which requires only that the plaintiff’s injury be fairly tracea-

ble to the defendant’s conduct.” Lexmark, 572 U.S. at 134 n.6.

An injury is not fairly traceable to a defendant’s conduct if the

causal chain is “attenuated,” Allen, 468 U.S. at 757, but Arti-

cle III requires no more than a “meaningful[] connect[ion]”

between the two, Dep’t of Ed. v. Brown, 600 U.S. 551, 568 (2023).

Put simply, a plaintiff must show “a substantial likelihood”

14 No. 23-1800

of causation. Duke Power Co. v. Envt’l Study Grp., Inc., 438 U.S.

59, 75 n.20 (1978).

The record includes both lay and expert testimony stating

that Costco’s pricing practices at least threatened the Green

Bay Stations with the financial injuries they described. For ex-

ample, the Green Bay Stations retained an expert witness,

Dingee, who explained that, because of Costco’s business

model, when a Costco warehouse enters a market for motor-

vehicle fuel, the inevitable result for a retailer already in that

market will be diminishing returns: it will be forced either to

lower its prices (and thus lose profits) or to maintain its prices

(and thus lose customers and, in turn, profits). Strenk testi-

fied, specific to the parties to this case, that he was reasonably

certain that the Bellevue Costco’s pricing practices would, at

a minimum, pose a threat of lost profits to the Green Bay Sta-

tions. And representatives for each of the Green Bay Stations

testified that they believed Costco’s practices caused the fi-

nancial injuries the stations claim to have experienced.

This evidence is enough to establish, for purposes of Arti-

cle III standing, a meaningful connection between Costco’s

pricing practices and the Green Bay Stations’ threat of injury.

Cf. Sanner v. Bd. of Trade of City of Chicago, 62 F.3d 918, 925–26

(7th Cir. 1995) (concluding that soybean farmers who were

forced to sell their product at a lower price had standing to

sue the Chicago Board of Trade where the allegations, taken

as true for purposes of a motion to dismiss, showed that a

conspiracy between the Board and several individuals

“played some role in setting the cash price for soybeans”). A

plaintiff who asserts that he suffered from lost profits can es-

tablish the traceability element of causation at the summary

judgment stage by “present[ing] some evidence that he has

No. 23-1800 15

lost money because [the defendant] forced him to set prices

artificially low” and that the customers “who purchased his

products would have paid more.” Slowiak v. Land O’Lakes, Inc.,

987 F.2d 1293, 1297 (7th Cir. 1993), overruled on other grounds

by Hill v. Tangherlini, 724 F.3d 965 (7th Cir. 2013). The Green

Bay Stations’ testimony does exactly that.

We readily acknowledge that the line between “specific”

and “conclusory” allegations is a fine one. But the testimony

submitted by the Green Bay Stations was precise enough to

allow Costco to identify the particular conduct that allegedly

harmed the stations. In that connection, we emphasize that

the question at this point of the analysis is not whether the

testimony proves that Costco’s pricing practices caused harm

to the Green Bay Stations, but only whether it is sufficient to

show a substantial likelihood of causation. To require any-

thing more than what the Green Bay Stations have submitted

would conflate the standing inquiry with a determination on

the merits. The evidence presented here is enough to establish

the traceability element for purposes of Article III standing,

and so we may proceed.

III

Before reaching the merits, we have a second preliminary

issue to resolve. The Green Bay Stations challenge the district

court’s order denying their motion to supplement Strenk’s ex-

pert report with his new analysis after the court refused to

admit the Kalibrate analysis. We review the district court’s

ruling for abuse of discretion. See Vance v. Ball State University,

646 F.3d 461, 469 (7th Cir. 2011).

The Green Bay Stations moved to supplement Strenk’s ex-

pert report on February 11, 2022. By that time, discovery had

16 No. 23-1800

been open for over two years, and nearly six months before

the motion Costco had disclosed its own expert report, which

included a cross-price elasticity analysis. Dispositive motions

on class certification and summary judgment were due in less

than three weeks, and yet, despite the looming deadlines, the

Green Bay Stations still allowed three weeks to pass after

Strenk informed Costco of his new analysis to file their motion

to supplement. On these facts, the district court was entitled

to conclude that allowing the supplement would be prejudi-

cial to Costco’s efforts to prepare its defense. “We regularly

affirm a district court’s decision to exclude supplemental evi-

dence in the interest of keeping cases moving forward,” id. at

469 (citing Pfeil v. Rogers, 757 F.2d 850, 858 (7th Cir. 1985)), and

we do so again here.

IV

We arrive, finally, at the merits of the appeal. As we ex-

plained at the outset, the Green Bay Stations claim that Costco

threatened them with, and actually caused them, financial in-

jury by engaging in motor-vehicle-fuel pricing practices that

violated the Act on 256 days. The district court found that for

238 of those days, Costco was entitled to immunity from the

Green Bay Stations’ claim pursuant to the meeting-competi-

tion exception to the Act. See Wis. Stat. § 100.30(6)(a)(7). For

the remaining 18 days, the court concluded that the Green Bay

Stations had failed to establish that Costco’s conduct caused

them to suffer an injury or threat of injury within the meaning

of the Act. The Green Bay Stations challenge each of those

conclusions. We evaluate the district court’s grant of sum-

mary judgment de novo, construing the record in the light

most favorable to the Green Bay Stations and drawing all

No. 23-1800 17

reasonable inferences in their favor. See Burton v. Downey, 805

F.3d 776, 783 (7th Cir. 2015).

A. The Meeting-Competition Exception

The Green Bay Stations argue that the district court erro-

neously concluded that the meeting-competition exception to

the Act immunizes Costco from liability on nearly all of the

alleged dates of violation. Costco qualifies for this exception

only if it was: (1) matching prices simultaneously offered by a

direct competitor, (2) compliant with the Act’s notification re-

quirement, and (3) price-matching in good faith. See 22

Shawano, LLC v. Dr. R.C. Samanta Roy Inst. of Sci. and Tech., Inc.,

709 N.W.2d 98, 101–02 (Wis. Ct. App. 2005) (noting that a re-

tailer who complies with the exception “is immune from lia-

bility in a private action”). We address these elements sequen-

tially.

1. Existing Price of a Direct Competitor

The meeting-competition exception does not apply unless

a retailer lowered its prices (or maintained already lowered

prices) to match the “existing price of a competitor,” Wis. Stat.

§ 100.30(6)(a)(7), which the Act in turn defines as “a price be-

ing simultaneously offered to a buyer for merchandise of like

quality and quantity by a person who is a direct competitor of

the retailer … of motor vehicle fuel … and from whom the

buyer can practicably purchase the merchandise,” id.

§ 100.30(2)(cj). Costco argues that it met the prices offered by

the Kaukauna BP and matched the five-cent discounted price

offered to customers of the Marathon Stations through

MakeItCount Rewards. It submitted evidence showing that it

lowered its prices to match those of the Kaukauna BP on 22

days and those of the Marathon Stations on 89 days, and that

18 No. 23-1800

for all but 18 of the days that its gasoline was priced below the

minimum markup price from October 1, 2019, to December

31, 2020, it was so priced in order to match one or the other of

these competitors.

For their part, the Green Bay Stations do not contest that

Costco matched the prices of the Kaukauna BP and the Mara-

thon Stations. They instead argue that Costco was not entitled

to match their prices for purposes of the exception.

i. Kaukauna BP

The Kaukauna BP is not a direct competitor of the Bellevue

Costco, the Green Bay Stations contend, because it is in a dif-

ferent and more distant geographic area than every other gas

station that Costco identifies as a direct competitor on its

“heat map.” They stress that the Kaukauna BP is not in the

city of Green Bay, that the land between Green Bay and

Kaukauna is only lightly developed, and that the Kaukauna

BP is roughly 24 miles from the Bellevue Costco. Moreover,

they say, although a separate Costco warehouse in Appleton,

Wisconsin, is closer to the Kaukauna BP than the Bellevue

Costco by nearly seven miles, the Appleton Costco does not

consider the Kaukauna BP to be its direct competitor. Costco

responds that the Kaukauna BP is a direct competitor because

the Bellevue Costco is competing for buyers who could (and

do) purchase gasoline from either retailer.

A decision from a Wisconsin intermediate court sheds

some light on the meaning of “direct competitor” for this pur-

pose. See Go America, 715 N.W.2d at 751. Without distinguish-

ing between “direct competitor” and “competitor,” the court

concluded that the phrase refers to “one selling or buying

goods or services in the same market as another.” Id. at 806

No. 23-1800 19

(quotation omitted). Go America thus indicates that, to resolve

whether the Kaukauna BP is the Bellevue Costco’s direct com-

petitor, we must define the relevant market. If Costco is sell-

ing gasoline in the same market as the Kaukauna BP, then the

two retailers are direct competitors.

We know from long experience with antitrust cases that an

elaborate definition of the relevant market is neither neces-

sary nor, in some cases, possible. See Federal Trade Commission

v. Indiana Federation of Dentists, 476 U.S. 447, 460–61 (1986)

(concluding that “the finding of actual, sustained adverse ef-

fects on competition [in the areas where the dentists] predom-

inated, viewed in light of the reality that markets for dental

services tend to be relatively localized, is legally sufficient to

support a finding that the challenged restraint was unreason-

able even in the absence of elaborate market analysis”). It of-

ten is enough to approximate the outer boundaries of a prod-

uct or geographic market.

For guidance on how to approximate the relevant market,

we consult the federal Merger Guidelines. The Guidelines

state: “A relevant antitrust market is an area of effective com-

petition, comprising both product (or service) and geographic

elements. The outer boundaries of a relevant product market

are determined by the ‘reasonable interchangeability of use or

the cross-elasticity of demand between the product itself and

substitutes for it.’” U.S. DEP’T OF JUSTICE & FED. TRADE

COMM’N, MERGER GUIDELINES 40 (2023) (quoting Brown Shoe

Co. v. United States, 370 U.S. 294, 325 (1962)). Because “‘fuzzi-

ness would seem inherent in any attempt to delineate the rel-

evant market,’” the Guidelines recommend identifying cer-

tain kinds of evidence that may help “to identify a relevant

antitrust market.” Id. (quoting United States v. Philadelphia

20 No. 23-1800

Nat’l Bank, 374 U.S. 321, 360 n.37 (1963) (ellipsis omitted)).

Helpful evidence includes “[d]irect evidence of substantial

competition between” retailers and “practical indicia,” “such

as … the product’s peculiar characteristics and uses, … dis-

tinct customers, … and specialized vendors.” Id. at 40–41.

The Merger Guidelines show that the Green Bay Stations

place far too much weight on geography in their attempt to

define the relevant market. The fact that the Kaukauna BP is

24 miles from the Bellevue Costco, and significantly further

from the warehouse than any of the other retailers that Costco

considers direct competitors, is not dispositive of whether the

two are direct competitors. Gasoline is a product for which

consumers can (and will) travel some distance. More broadly,

the point is that we must attend not only to geography, but

also to the specific characteristics of the product being offered

and the customers to whom it is being offered, among other

practical considerations.

Following that approach, it is evident that Costco shares a

market with the Kaukauna BP. As we have noted several

times, the parties agree that 236 Costco members with an ad-

dress-of-record in Kaukauna have purchased gasoline at the

Bellevue Costco during the applicable 458-day period. These

customers are distinct, insofar as they are members of Costco.

But to point out that fact is merely to highlight that Costco has

a unique membership structure: unlike the typical customer

of the Kaukauna BP, a person who is a member of Costco can

take advantage of any of its services, including its gasoline

pumps. And, as the testimonies of numerous Costco members

show, it is not uncommon to purchase gasoline at Costco

while visiting the warehouse to purchase other products.

Costco thus has an interest in encouraging its members who

No. 23-1800 21

reside in Kaukauna to purchase gasoline at the Bellevue ware-

house—i.e., to compete with the Kaukauna BP for customers.

We add that it is far from impracticable for a Costco mem-

ber with an address-of-record in Kaukauna to purchase gaso-

line at the Bellevue Costco, rather than at the Kaukauna BP. A

person easily could drive 24 miles on very little gasoline; they

might already have planned to visit the warehouse for some

other product or service and simply added gasoline to the list.

Alternatively, they might be in the area for some other reason

and choose to take advantage of their Costco membership by

filling up their tank.

In sum, we conclude that, owing to its membership struc-

ture, Costco’s direct competitors should be determined not

simply based on the location of the stations, but also on the

addresses-of-record of its members. Although there might be

some number of customers that is too few to establish the nec-

essary competition, we need not decide here where the lower

threshold lies. We are confident that the existence of 200-plus

buyers who could practicably purchase gasoline from either

the Kaukauna BP or Costco places those two retailers in the

same motor-vehicle-fuel market and thus makes them direct

competitors for purposes of the Act.

ii. Marathon Stations

Costco did not lower its prices to match only the

Kaukauna BP’s prices; on some days, it lowered or matched

the prices offered by the Marathon Stations. The Green Bay

Stations argue that the Marathon Stations are not direct com-

petitors of Costco, but for a different reason than they be-

lieved the Kaukauna BP is not. They do not dispute that the

Marathon Stations are in the same market as Costco or that

22 No. 23-1800

buyers could practicably purchase gasoline from any of those

three retailers. Rather, seizing onto the statutory language

stating that an “[e]xisting price of a competitor” is a “price

being simultaneously offered to a buyer,” Wis. Stat.

§ 100.30(2)(cj) (emphasis added), they argue that the Mara-

thon Stations advertised only the sticker price to buyers, not

the five-cent reduced price available through MakeItCount Re-

wards, and thus did not “offer” the discounted price to its cus-

tomers.

As the district court noted, the text of the Act does not re-

strict a retailer to matching the posted price of its competitors.

The terms are broad enough to allow for the matching of any

price offered to a buyer, whether that price is advertised or

not. Costco was therefore entitled to match the prices offered

through MakeItCount Rewards, notwithstanding the fact that

the Marathon Stations did not advertise them.

The Green Bay Stations insist that this interpretation of the

Act is incorrect. As support, they point to two sources: a deci-

sion from a Wisconsin state trial court and a regulation prom-

ulgated by the Department that interprets the meeting-com-

petition exception. The former does not help their position, as

our role as a federal court sitting in diversity is to ascertain

how the state appellate courts would interpret the Act. See

West v. American Tel. & Tel. Co., 311 U.S. 223, 237–38 (1940).

The Wisconsin appellate courts consistently have stated that

courts “should not read into the statute language that the leg-

islature did not put in.” Brauneis v. State, Labor and Industry

Review Comm’n, 612 N.W.2d 635, 644 (Wis. 2000) (citing In re

G. & L.P., 349 N.W.2d 743 (Wis. 1984)). We cannot, consistent

with this principle of construction, interpret “offered to the

buyer” as “advertised to the buyer” or “offered to the buyer

No. 23-1800 23

in the form of an advertisement,” as the Green Bay Stations

would have us do.

The Department’s regulation provides that “[a] price for

merchandise meets an existing price of a competitor under

[the Act] only if the merchandise in question is sold on a day

when the competitor’s price is in effect and is offered under

the same terms and conditions as the competitor’s offer.” Wis.

Admin. Code § ATCP 105.009. The Green Bay Stations argue

that Costco offered different “terms and conditions” to buyers

than the Marathon Stations.

The state agency’s interpretation of the Act is less helpful

than the Green Bay Stations think. Wisconsin courts no longer

defer to administrative agencies’ conclusions of law, but they

do “give ‘due weight’ to the experience, technical compe-

tence, and specialized knowledge of an administrative

agency.” Tetra Tech EC, Inc. v. Wisconsin Dep’t of Revenue, 914

N.W.2d 21, 63 (Wis. 2018). That said, we need not decide how

much weight to give to the Department’s regulation. Even as-

suming that its interpretation of the Act is correct, the Green

Bay Stations would not prevail because Costco did offer the

same terms and conditions as the Marathon Stations. Anyone

can become a member of either Costco or the MakeItCount Re-

wards program (or both), and neither Costco nor the program

placed gallon restrictions on their prices. The sole difference

between the programs—that Costco members must pay a

small membership fee—is immaterial because Costco does

not compete for motor-vehicle-fuel buyers who are not al-

ready members. Thus, to the extent that the regulation sheds

light on the meaning of the Act, it does not undermine our

conclusion.

24 No. 23-1800

The Act places no limitation on what prices a retailer may

match; it says only that they must be offered to a buyer. The

Marathon Stations are in the same market as Costco and they

offered the MakeItCount Rewards prices to all customers.

Costco was therefore permitted to match the prices of those

retailers. Accordingly, for 238 of the days at issue, Costco was

matching the prices offered by its direct competitors.

2. The Notification Requirement

A retailer cannot claim immunity simply by showing that

it lowered its prices to match those offered by a direct com-

petitor; it must also satisfy the Act’s notification requirement.

The Act states that “[i]f a retailer … of motor vehicle

fuel … lowers in good faith the price of motor vehicle fuel be-

low [the minimum markup price] under [the meeting-compe-

tition exception], the person shall submit to the [D]epartment

notification of the lower price before the close of business on

the day on which the price was lowered[.]” Wis. Stat.

§ 100.30(7)(a). A retailer’s failure to comply with this require-

ment does not prevent it from asserting a defense under the

Act. It merely “creates a rebuttable presumption” that the re-

tailer did not lower its prices to meet the existing price of a

competitor. Id. § 100.30(a)(b).

The district court concluded that, although Costco inad-

vertently submitted notifications to the Department listing the

incorrect competitor on fifty days in which it lowered its

prices to match a competitor, Costco overcame the presump-

tion that it did not lower its price for a permissible purpose

by introducing business records confirming its compliance

with the requirements of the exception. On appeal, the Green

Bay Stations do not challenge the court’s conclusion. Wisely

so: the Act allows a retailer to introduce business records

No. 23-1800 25

maintained in the usual course of business to prove that it

matched the prices of a direct competitor. See id.

§ 100.30(6)(a)(7). Costco introduced spreadsheets that it calls

its “Comp Shop Log,” which it updated daily during the rel-

evant period whenever it matched the price offered by a com-

petitor. That document was maintained in its usual course of

business, and so it falls within the “other business record”

catchall listed in the notification-requirement provision of the

Act. This suffices to rebut the presumption that Costco’s occa-

sional, unintentional non-compliance with the notification re-

quirement removes it from the safe harbor of the meeting-

competition exception.

3. Good Faith

The final element of the statutory exception requires an in-

quiry into Costco’s motive or intent. The Act states that a re-

tailer’s decision to lower prices to match those of a competitor

must be “made in good faith[.]” Wis. Stat. § 100.30(6)(a)(7).

Although the Wisconsin courts have been “reluctant to re-

solve” where the burden of proving good (or bad) faith falls,

see Go America, 715 N.W.2d at 754–55, the case law offers some

clues. In Go America, the Wisconsin Court of Appeals assumed

for purposes of argument that the defendant affirmatively

had to demonstrate its good faith. The defendant introduced

testimony that it surveyed its competitors’ gasoline prices

daily in order to match them, and it submitted copies of its

price surveys to support that testimony. The plaintiff, by con-

trast, failed to introduce anything to “show or create a reason-

able inference to the contrary.” Id. at 756. On that record, the

court concluded that the defendant had price-matched in

good faith.

26 No. 23-1800

The evidence tending to show Costco’s motive is substan-

tially identical to the evidence presented by the defendant in

Go America. Costco has introduced evidence that it monitored

its competitors on a daily basis, made efforts to comply with

the notification requirement, and kept business records to

show its diligence even when it did not notify the Department

of its price-matching. The Green Bay Stations, on the other

hand, can point only to complaints against Costco submitted

to the Department. But unsubstantiated complaints do not

reasonably give rise to an inference of bad faith, and so even

assuming Costco must establish its good faith, it has done so.

B. The Elements of the Act’s Private Right of Action

The Green Bay Stations next argue that the district court

erroneously concluded that they failed to establish that

Costco’s pricing practices caused them to suffer an injury or

threat of injury. Because Costco has shown that it is entitled

to immunity under the meeting-competition exception for 238

of the days at issue, we need decide only whether Costco in-

jured or threatened the Green Bay Stations with injury on the

remaining 18 days. See supra n.1. The burden is on the Green

Bay Stations to establish each element of their claim. See Hei-

den v. Ray’s Inc., 150 N.W.2d 467, 470–71 (Wis. 1967).

Like the district court, we begin with the statutory element

of causation. To determine whether the Green Bay Stations

have carried their burden of proving causation, we must first

determine what it means for a person to be “injured or threat-

ened with injury as a result of a sale or purchase of motor ve-

hicle fuel” below the minimum markup price. Wis. Stat.

§ 100.30(5m) (emphasis added). Although the Wisconsin

courts have not considered what theory of causation is incor-

porated into the Act by that phrase, they long have held that

No. 23-1800 27

a person’s conduct causes a particular result when it is a sub-

stantial factor in producing that result. See, e.g., Lang v. Bau-

mann, 251 N.W. 461 (Wis. 1933); Fischer by Fischer v. Ganju, 485

N.W.2d 10 (Wis. 1992). The Act, which was adopted shortly

after Baumann, thus requires the Green Bay Stations to show

that Costco’s pricing practices were a substantial factor in

causing their lost profits.

In their effort to make that showing, all but one of the

Green Bay Stations exclusively rely on the expert reports pre-

pared by Strenk and Dingee. As we explained earlier, Strenk

testified, without data, that he could conclude “to a reasona-

ble degree of certainty” that the Bellevue Costco at least

threatened the Green Bay Stations’ sales volume. Both of the

experts testified that a Costco entering a market would

threaten existing retailers with injury. One plaintiff, Tikapur

Petroleum, LLC, also submitted a declaration of a corporate

representative who stated that his “general observation” was

that his profits and sales were declining and that he “believed

this was attributable to Costco’s low gas pricing.”

The evidence the Green Bay Stations offer is not sufficient

to prove causation for purposes of the Act. In the absence of

any rigorous market or economic analysis (or even evidence

that at least one customer actually elected to purchase gaso-

line from Costco rather than from the Green Bay Stations be-

cause Costco offered lower prices), the testimony upon which

the Green Bay Stations rely amounts to little more than “sheer

speculation,” which the Wisconsin Supreme Court has held is

insufficient to establish an element of the Act’s private cause

of action. Heiden, 150 N.W.2d at 638–39. Indeed, in Heiden, the

court went so far as to say that a proven fact of a single inci-

dent of a lost sale is not “sufficient to establish a prima facie

28 No. 23-1800

loss or threat of injury.” Id. at 638. The Green Bay Stations

have not introduced evidence that Costco’s pricing practices

caused even one lost sale. They thus have failed to establish

causation, which is an essential element of their claim. This

means that Costco is entitled to summary judgment on the re-

maining 18 days stated in the complaint.

V

The Act exists to prevent “unfair method[s] of competition

in commerce,” not to interfere with retailers “who maintain a

fair price policy.” Wis. Stat. § 100.30(1). When a retailer of mo-

tor-vehicle fuel complies with the requirements the statute

imposes on its ability to match the prices of a direct competi-

tor, it is engaged in lawful competition. And even when it

does not, a plaintiff cannot obtain judicial relief unless it can

establish the essential elements of the private right of action.

The Green Bay Stations have failed to raise a triable issue of

fact with respect to causation, and thus they cannot prevail.

The judgment of the district court is AFFIRMED.