                               In the

United States Court of Appeals
                For the Seventh Circuit

Nos. 12-1109, 12-1224

IN RE:

    S ULFURIC A CID A NTITRUST L ITIGATION.

A PPEAL OF:

    O HIO C HEMICAL S ERVICES, et al.,
                                                               Plaintiffs,
C ROSS-A PPEAL OF:

    F ALCONBRIDGE, L TD., et al.,
                                                             Defendants.


             Appeals from the United States District Court
         for the Northern District of Illinois, Eastern Division.
           No. 03 C 4576—James F. Holderman, Chief Judge.



  A RGUED S EPTEMBER 21, 2012—D ECIDED D ECEMBER 27, 2012




  Before P OSNER, K ANNE, and S YKES, Circuit Judges.
  P OSNER, Circuit Judge. This is a class action suit under
section 1 of the Sherman Act, 15 U.S.C. § 1, that after
certification of the class was dismissed on the merits
when shortly before the trial was scheduled to begin
2                                       Nos. 12-1109, 12-1224

the district judge ruled that the case could not go to trial
on a theory of per se liability. The plaintiffs could have
gone to trial on a theory of liability under the rule of
reason, but preferred to appeal the dismissal, hoping
we would order the reinstatement of their per se case.
The dismissal is final because the plaintiffs have made
clear that the case is over if they are not allowed to try
it as a per se case.
  The class consists of chemical companies that purchase
sulfuric acid as one of the inputs into their production of
chemicals. The defendants own smelters that process
nonferrous minerals such as nickel and copper. They
also produce sulfuric acid and sell or sold it to the mem-
bers of the class.
   The defendants cross-appeal, asking that if (but only
if) we reverse the dismissal of the suit, we decertify the
class. The purpose of the “only if” qualification is to
make the judgment bind the entire class if we affirm the
dismissal, which it would not do if the class were decerti-
fied. See Smith v. Bayer Corp., 131 S. Ct. 2368, 2380 (2011).
If we reverse, and allow the class members to press
their theory of per se liability, the defendants would
prefer to fight the class members one by one, which
would be the result of decertification of the class, rather
than have to face all of them in a single trial that could
produce a monstrous judgment. It is such threats of
ruin that force most defendants in class action suits to
settle if a class is certified. In re Rhone-Poulenc Rorer, Inc.,
51 F.3d 1293, 1299-1300 (7th Cir. 1995).
  The abiding puzzle of the plaintiffs’ appeal is why the
lawyers for the class, having spent almost nine years
Nos. 12-1109, 12-1224                                         3

litigating the case in the district court, refused to go to
trial. Though the trial would have been governed by
the rule of reason, probably all that this would have
meant in a case such as this is that the defendants
would have had greater latitude for offering justifica-
tions for what the plaintiffs claim is a price-fixing con-
spiracy than if the standard governing the trial had
been the per se rule, which treats price fixing by competi-
tors as illegal regardless of consequences or possible
justifications. Texaco Inc. v. Dagher, 547 U.S. 1, 5 (2006). The
plaintiffs do not concede that the conduct they challenge
was reasonable and therefore lawful; but their refusal to go
to trial under the rule of reason suggests that they
expected a jury to find that it was.
   From remarks by their lawyer at the oral argument
we infer that they think that in a trial governed by the
rule of reason they would have had to prepare a
radically different case in chief, proving not only that the
defendants fixed prices (all they’d have to prove, besides
damages, in a per se case), but also that the defendants
had market power (that is, the power to raise price
above the competitive level without losing so much
business to other sellers that the price would quickly
fall back to the competitive level) and that their collusive
activity was indeed anticompetitive. Doubtless in most
cases the prima facie case under the rule of reason
requires proof “that the defendant has sufficient market
power to restrain competition substantially,” as we said
in General Leaseways, Inc. v. National Truck Leasing Associa-
tion, 744 F.2d 588, 596 (7th Cir. 1984). But a plaintiff who
proves that the defendants got together and agreed to
4                                      Nos. 12-1109, 12-1224

raise the price (whether directly or by restricting
output, which would have the same effect) that he paid
them to buy their products—which is what the plaintiffs
in this case would have had to prove under the per se
rule to establish liability and obtain damages—has made
a prima facie case that the defendants’ behavior was
unreasonable. He need not prove market power; even
though by definition without it a firm or group of firms
can’t harm competition, it is not a part of the prima facie
case of illegal per se price fixing. E.g., National Collegiate
Athletic Association v. Board of Regents, 468 U.S. 85, 109-10
(1984). But even if a challenged practice doesn’t quite
rise to the level of per se illegality, it may be close
enough to shift to the defendant the burden of showing
that appearances are deceptive and really the behavior
that the plaintiffs have challenged is not anticompetitive.
Of course there would be more work for the plaintiffs if
the defendants in this case were able to create a triable
issue of justification, but, as we have just explained,
probably less than they think.
   But this is a detail; the question is whether the judge
was right to think this a rule of reason case. Before
turning to that question, we address briefly the plain-
tiffs’ argument that the district court’s ruling on the
question was not only substantively unsound but proce-
durally irregular. The district judge who had handled the
lengthy pretrial proceedings in this case had retired and
the case had been reassigned. The original judge, in
denying summary judgment (except on one issue) for the
defendants, had, rather oddly, refused to decide whether
Nos. 12-1109, 12-1224                                       5

the case should proceed as a per se case or a rule of reason
case. After the case was reassigned and a trial date set,
the defendants became concerned that they didn’t
know what kind of trial to prepare for, so they asked
the judge to decide, and he said rule of reason. His
ruling was abrupt and not explained, but whether it
was correct is a question of law that we can decide
without benefit of an analysis by the district judge. See
Deutscher Tennis Bund v. ATP Tour, Inc., 610 F.3d 820, 829
n. 7 (3d Cir. 2010).
   So let’s decide it; concretely, let’s decide whether the
challenged practices are the sort that fall within the
scope of the per se rule against price fixing, or fall outside
it in which event the judge was right to rule that a trial
would be governed by the rule of reason.
  The principal defendants are Noranda, Inc. and
Falconbridge Ltd., Canadian mining companies that in
2005, after the period of the alleged antitrust violations
(1988-2002), merged to form a single company named
Xstrata Canada. During the relevant period Noranda
owned between 46 and 60 percent of Falconbridge’s
common stock, and as a result controlled Falconbridge.
They thus were affiliated rather than independent pro-
ducers, and in fact pooled and jointly sold their
sulfuric acid.
  The smelting of nonferrous minerals generates sulfur
dioxide as a byproduct, and sulfur dioxide reacts with
the water vapor in the atmosphere to create sulfuric
acid, which is the acid in acid rain. For environmental
reasons the Canadian government requires the mining
6                                     Nos. 12-1109, 12-1224

companies to process the sulfur dioxide into sulfuric acid,
which unlike sulfur dioxide does not enter the atmosphere
and so does not contribute to the formation of acid rain.
Although there is a market for sulfuric acid—it is used in
manufacturing fertilizer, paper, and other prod-
ucts—Noranda and Falconbridge didn’t want to produce
the acid because the Canadian market for it is limited and
what is not sold is costly to store or—because of further re-
strictions imposed by the Canadian government to
protect the environment—to dispose of other than by
sale. When in the mid-1980s the government increased
the amount of sulfur dioxide that smelters were re-
quired to capture, Noranda had to build a large new
sulfuric acid plant at one of its smelter sites in order to
be in compliance with the new requirement.
  Thus at the same time that Noranda was involuntarily
contributing to the solution of the acid rain problem, it
was compounding its own problem (its “personal” prob-
lem as it were) of excess production of sulfuric
acid—excess because as we said it is a product costly to
store or dispose of and difficult to find a market for in
Canada. And so in the 1980s Noranda and Falconbridge
began looking at the large U.S. market for sulfuric
acid. Having virtually no capability for distributing their
acid in the United States—no distributors, no customer
relationships—they had to create a U.S. distribution
network if they wanted to sell sulfuric acid in this coun-
try. The logical candidates for such a network were the
U.S. producers of sulfuric acid. Although sulfuric acid
was an unwanted byproduct of the smelting operations
of Canadian mining companies, chemical companies in
Nos. 12-1109, 12-1224                                      7

the United States manufactured it from sulfur and
sold it to firms that used it in their own manufacturing.
The domestic U.S. production of sulfuric acid (called
“virgin acid”) was not very profitable, however, so the
Canadian companies saw an opportunity to persuade
the producers to distribute the Canadian companies’
sulfuric acid (“smelter acid”) in lieu of producing their
own. The U.S. companies are also the distributors
of the sulfuric acid they produced and so had the
customer relationships necessary for distribution of the
Canadian companies’ acid in the United States.
  The effort at persuasion was successful. The U.S. pro-
ducers were willing to curtail production and devote
their distribution facilities to the Noranda-Falconbridge
acid and be compensated by the difference between
what the Canadian companies would charge them for
sulfuric acid and what they could resell it for to the U.S.
consumers of the acid. The U.S. producers were afraid
that unless they agreed to become distributors for the
Canadian companies the latter would create their own
U.S. distribution network and underprice the U.S. pro-
ducers, thereby driving them out of the sulfuric acid
market rather than keeping them in as distributors of
the Canadian acid. As one producer put it, “they [Noranda
and Falconbridge] are leaving a path of destruction in
their wake. They have not picked up any business
without decreasing the pricing at least $10-$15 per ton
to the customer, and the threat of their participation [in
the U.S. market] is causing [other U.S. producers] to
significantly reduce pricing in an effort to maintain” sales.
8                                    Nos. 12-1109, 12-1224

  Apparently Noranda and Falconbridge were not
content to wait for the economics of the sulfuric acid
market to convince the U.S. producers to stop produc-
ing. For the two Canadian companies entered into con-
tracts with several U.S. producers that provided that
in exchange for becoming a distributor of the Canadian
companies’ sulfuric acid (and with an exclusive
territory in which to distribute it), each producer would
curtail its own production and be compensated for this
by the Canadian companies’ selling sulfuric acid to it
(for resale) cheaply enough to make distribution
more profitable than production. These “shutdown
agreements” are the main focus of this case. The plaintiffs
argue that by reducing total sales of acid in the United
States, the agreements raised the market price, and that
an agreement to restrict output and therefore raise
price is the per se illegal offense of price fixing.
  This is a possible interpretation of the shutdown
agreements, and if it were the only plausible one this
would indeed be a per se price-fixing case. But it is not
the only plausible interpretation. If you are Noranda
and Falconbridge, gazing into the American market for
sulfuric acid, you see opportunity but also risk. The
opportunity is to make money from your unwanted
byproduct of mining. For this you need distribution. The
U.S. producers of the acid are the firms that can
undertake distribution in the United States. But as they
are also producers, you have to worry about the effect
of their production on the profitability of your
venturing into the U.S. market.
Nos. 12-1109, 12-1224                                    9

  We do not know much about the cost structure of the
Canadian companies’ acid; the plaintiffs haven’t told
us what we would need to know in order to be
persuaded by them that the shutdown agreements are
garden-variety price-fixing agreements. What we do
know is that the Canadian companies incur costs both
in converting sulfur dioxide into sulfuric acid and in
transporting it to market, that the acid is costly to
transport because it is extremely corrosive and special
equipment and training are therefore required for its
safe transportation, and that most buyers of sulfuric acid
in the United States are located far from the Canadian
smelters. Suppose the U.S. distributors of sulfuric acid,
being themselves producers, decided to continue pro-
ducing. Supply, being augmented by the shipments of
the Canadian companies into the United States, would
now greatly exceed demand, and prices might plummet
to a level at which it was no longer profitable for the
Canadian companies to incur the costs of trying to sell
their sulfuric acid in the United States.
  They might be willing to sell their acid at a loss,
because they might lose even more money if as a result
of ceasing to export the acid they had to close down
some of their smelters or build new sulfuric acid plants
in order to comply with Canadian environmental reg-
ulations. But if therefore they sold their acid in the
United States at a loss, the U.S. producers might bring
antidumping proceedings against them, arguing that the
Canadian companies were selling below their cost in
Canada. See generally Harvey Kaye & Christopher A.
Dunn, International Trade Practice §§ 15:1, 19:2 (2012). We
10                                      Nos. 12-1109, 12-1224

don’t know whether the Canadian companies could
defend successfully by proving that they would lose
even more money by not selling below cost, because of
the losses they would incur by closing down some of
their smelters or building new sulfuric acid plants, in
which event their loss selling in the United States would
be in a relative sense profitable.
  The Canadian companies might also be troubled by
the prospect of distributing their sulfuric acid through
companies that are also competitors by virtue of pro-
ducing their own sulfuric acid. It is not per se illegal to
insist that a distributor agree not to carry a competing
line of goods to the supplier’s, Roland Machinery Co.
v. Dresser Industries, Inc., 749 F.2d 380, 394 (7th Cir. 1984);
11 Herbert Hovenkamp, Antitrust Law ¶ 1820, pp. 174-79
(3d ed. 2011); what difference should it make that
the competing line is produced by the distributor him-
self? And so the shutdown agreements might be found to
be an innocent species of exclusive dealing.
  Our analysis suggests that had it been the rule, when the
Canadian companies were contemplating entry into the
U.S. market, that shutdown agreements (or some equiva-
lent, like requirements contracts) would be per se viola-
tions of U.S. antitrust law, the companies might have
been deterred from entering—and the price of sulfuric
acid in the United States would be higher. Moreover,
given the cost advantage of the Canadian companies
and the fact that a number of U.S. producers got out of
the business of producing sulfuric acid because they
knew they couldn’t compete with those companies and
Nos. 12-1109, 12-1224                                        11

so couldn’t remain in the sulfuric acid business
without signing shutdown agreements, the effect of the
agreements on price and output may have been merely
to accelerate slightly an inevitable trend created by the
Canadian companies’ entry into the U.S. market.
  An alternative to the shutdowns might have been for
the Canadian companies to negotiate long-term supply
contracts with the U.S. firms, but it is not suggested by
the plaintiffs and it is not clear that the effects would
be different from the effects of the shutdown agreements.
For if the U.S. firms obtain their supply of sulfuric acid
from the Canadian companies, they won’t be producing
acid themselves.
  The shutdown agreements are a form of price fixing,
but we know from Broadcast Music, Inc. v. Columbia Broad-
casting System, Inc., 441 U.S. 1, 24 (1979), that even
price fixing by agreement between competitors—and from
Polk Bros., Inc. v. Forest City Enterprises, Inc., 776 F.2d 185,
189 (7th Cir. 1985), that other agreements that restrict
competition, as well—are governed by the rule of reason,
rather than being per se illegal, if the challenged
practice when adopted could reasonably have been
believed to promote “enterprise and productivity.” Id.
The entry of Noranda and Falconbridge into the U.S.
sulfuric acid market was likely to result in an eventual
fall in the price of acid in that market, an unequivocally
socially beneficial effect from an economic standpoint.
If the agreements facilitated that entry, their net effect
on economic welfare may well have been positive, espe-
cially since the negative effects may have been few be-
cause of the higher production costs of the U.S. companies.
12                                    Nos. 12-1109, 12-1224

   The plaintiffs point out that both the BMI and Polk
opinions describe competitive restrictions that are de-
fensible as “ancillary” to (that is, supportive of) socially
beneficial business endeavors that create a new “product.”
The Court in BMI upheld what amounted to a price-
fixing arrangement among composers on the ground that
it created a new “product,” namely a blanket copyright
license that greatly reduced the cost of license negotia-
tions. Were it not for blanket licensing, every composer
of music would have to negotiate a copyright license
separately with hundreds or even thousands of radio
stations, nightclubs, and other performance venues, and
each radio station, etc., would have to negotiate
separately with hundreds of composers. But equally the
shutdown agreements could be regarded as enabling or
assisting in enabling a new product in the U.S. economy,
namely Canadian smelter acid. Anyway “product” talk
is an unnecessary and distracting embellishment of the
rule of reason. The blanket licenses in BMI were not a
product, new or old, but a contractual instrument for
marketing music, which was the product. The rule of
reason directs an assessment of the total economic
effects of a restrictive practice that is plausibly argued
to increase competition or other economic values
on balance.
  Pretrial discovery had supplied the plaintiffs with all
the evidence they needed in order to be able to make a
prima facie case of price fixing. So at least they believed
and we can assume without deciding that they were
right. But, to repeat an earlier point, if they were right,
then all that the rule of reason would have done to alter
Nos. 12-1109, 12-1224                                     13

the litigation would have been to allow the defendants
to defend at trial by showing that the shutdown agree-
ments, even if they could be thought a form of price
fixing or output restriction, were on balance procompeti-
tive because they facilitated the entry of very low-cost
producers into the U.S. market. That benefited U.S. chemi-
cal companies that use sulfuric acid as an input (and
are paradoxically the plaintiffs in this class action
suit—biting the hand that fed them), and ultimately to
the consumers of the products that those companies make.
  It is relevant that we have never seen or heard of an
antitrust case quite like this, combining such elements
as involuntary production and potential antidumping
exposure. It is a bad idea to subject a novel way of doing
business (or an old way in a new and previously unex-
amined context, which may be a better description of
this case) to per se treatment under antitrust law. Leegin
Creative Leather Products, Inc. v. PSKS, Inc., 551 U.S. 877,
886-87 (2007); Broadcast Music, Inc. v. Columbia Broadcasting
System, Inc., supra, 441 U.S. at 9-10. The per se rule is
designed for cases in which experience has convinced
the judiciary that a particular type of business practice
has no (or trivial) redeeming benefits ever.
   The plaintiffs deny that this is a novel case—they say
it’s a rerun of United States v. Socony-Vacuum Oil Co., 310
U.S. 150 (1940), the famous “hot oil” case. There was a
chronic oversupply of oil during the Great Depression.
This was in part because subsurface geological changes
had made it difficult (given the then-existing technology)
for producers to reactivate wells once they had been
14                                    Nos. 12-1109, 12-1224

abandoned, and so they were reluctant to take them out
of service even when demand for oil was low, and in
part because many of the smaller independent refiners,
lacking storage space, could not hold any of their
output off the market but had to dump it. The resulting
oversupply depressed prices throughout the market.
The large refiners agreed among themselves to buy a
portion of the small refiners’ output and hold it off the
market in order to raise the price for the large refiners’
own oil. In effect the big refiners were paying the small
ones not to sell, just as—the plaintiffs argue—in
our case Noranda and Falconbridge were paying U.S.
producers of sulfuric acid not to produce. The difference
is that the only aim and effect of the price-fixing agree-
ment in Socony-Vacuum were to raise price; in this case
the aim was to facilitate entry into the U.S. market,
which would (and eventually did, as we’ll see) lower
prices and prevent the shutdown of Canadian smelting
operations, which would have reduced output and raised
the price of sulfuric acid in the United States. The
overall effect was thus to lower rather than to raise price.
The plaintiffs’ claim that the price would have been
even lower without the shutdown agreements is
doubtful, as we have said, because without the agree-
ments the Canadian companies might not have entered
the U.S. market.
  The plaintiffs retreat to the general language in the
Socony-Vacuum opinion, an opinion 72 years old and
showing its age. They quote from the opinion that “any
combination which tampers with price structures is
engaged in an unlawful activity.” Id. at 221. Taken
Nos. 12-1109, 12-1224                                     15

literally the quotation would outlaw resale price mainte-
nance, which is no longer illegal per se, see Leegin Creative
Leather Products, Inc. v. PSKS, Inc., supra, 551 U.S. at 894,
as well as the agreements upheld in the BMI and Polk
Bros. cases.
  The plaintiffs do not rest their case entirely on the
shutdown agreements. They point also to Noranda
and Falconbridge’s grant of exclusive territories to
their U.S. distributors, which by preventing competition
among the distributors shored up the shutdown agree-
ments. The argument is that the Canadian companies
compensated the distributors for giving up their produc-
tion by cutting them in on the supracompetitive profits
that eliminating competition can, and in this case
according to the plaintiffs did, enable; and so the dis-
tributors’ spread—the difference between what they
paid their Canadian suppliers and what they charged
their customers—was fattened as a way of sharing out
the supracompetitive profits between them and the
Canadian companies. Without exclusive territories the
distributors would have competed with each other and
in doing so might have competed away their share of
the supracompetitive profits.
  But there is another way to look at the exclusive ter-
ritories. When the Canadian companies went to
American producer-distributors and said we’re entering
the market with our very cheap sulfuric acid and we
want you to convert from being producers of acid and
distributors to being just distributors of our acid, they
were asking the producer-distributors to take a big
risk by changing their business model. One way to com-
16                                     Nos. 12-1109, 12-1224

pensate them for taking that risk was to insulate
them from competition at the distribution level. Exclusive
territories reduce competition at the distributor level
but can increase it at the producer level and in this case
may well have done so by facilitating the Canadian pro-
ducers’ entry into the U.S. market. See Continental T.V.,
Inc. v. GTE Sylvania Inc., 433 U.S. 36, 54-57 (1977).
   In 1998 Noranda and Falconbridge formed a joint
venture with DuPont to supply sulfuric acid to the U.S.
market, and the plaintiffs argue that they did so solely
to eliminate competition with DuPont and so the joint
venture was another per se violation. The joint venture
pooled the acid output of all three companies, and,
more important (remember that Falconbridge was an
affiliate of Noranda; there is no indication that the two
firms had ever competed with each other in the sulfuric
acid market), made DuPont’s very extensive U.S. dis-
tribution network available to the Canadian companies.
A further anticipated economy was that DuPont would
sell the Canadian companies’ sulfuric acid jointly with
its other chemicals, providing one-stop shopping to
buyers of a variety of chemicals. Noranda and
Falconbridge could not do that on their own because
they are mining companies, not chemical companies,
except (so far as appears) for their involuntary production
of sulfuric acid.
  The joint venture enabled substantial economies in
transportation and marketing and after it was launched
the price of sulfuric acid in the United States dropped
significantly. Yet the plaintiffs argue that the joint venture
was spurious. If two or more competing firms, wanting to
Nos. 12-1109, 12-1224                                    17

fix prices, agreed to form a joint venture to sell their
output at a price agreed on by the parties, the designation
of the price-fixing agreement as a joint venture would not
save it from being adjudged illegal per se. Texaco Inc. v.
Dagher, supra, 547 U.S. at 5-6 and n. 1; Starr v. Sony
BMG Music Entertainment, 592 F.3d 314, 326 (2d Cir.
2010); Addamax Corp. v. Open Software Foundation, Inc., 152
F.3d 48, 52 (1st Cir. 1998); 13 Hovenkamp, supra, ¶ 2132,
pp. 187-200. But as also explained in the cases and treatise
that we’ve just cited, if a joint venture has a legitimate
business purpose, as the defendants’ joint venture with
DuPont did, the fact that as part of the venture the prices
of the venturers are coordinated does not condemn it
out of hand, but instead subjects it to scrutiny under
the rule of reason. If the coordination is ancillary to
(that is, supportive of) the legitimate business purpose of
the venture, it may be permissible—a rule of reason
question.
  The plaintiffs argue that this venture was illegitimate
because by organizing it as a limited liability company
rather than as a conventional stock corporation, and also
by leaving almost all the assets it needed with Noranda
and Falconbridge, the venturers avoided (or at least
claimed to be entitled to avoid) registering the proposed
venture with the Federal Trade Commission under the
Hart-Scott-Rodino Act. See “Premerger Notification:
Reporting and Waiting Period Requirements,” 64 Fed.
Reg. 34804-02 (June 29, 1999); 15 U.S.C. §18a(a)(2)(B)(ii);
16 C.F.R. § 801.40. But so what? The plaintiffs think that
if the joint venture violated that Act, the defendants
must be guilty of per se illegal price fixing. That is a non
sequitur. If there were no joint venture, there would still
18                                    Nos. 12-1109, 12-1224

be no per se violation for there would still be the
legitimate business reasons for the defendants to have
cooperated with DuPont—indeed nothing bearing on
the economic consequences of the arrangement would
be altered.
  In summary, we agree with the district court’s order re-
jecting the plaintiffs’ request to limit the trial to their
claims of per se violation of antitrust law. But we disagree
with an alternative ground of affirmance that the defen-
dants urge—that the four-year antitrust statute of lim-
itations expired before the suit was filed—and we think
it important to register our disagreement in order to
head off such an argument in future cases. The
argument depends on an assumption that the statute of
limitations in an antitrust case begins to run as soon as
the antitrust injury (in this case, the alleged effect of the
shutdown agreements, territorial restrictions, and joint
venture in preventing the U.S. price of sulfuric acid
from falling as low as it would otherwise have fallen)
occurs, rather than when it is discovered (which may
be later). That is incorrect. In re Copper Antitrust
Litigation, 436 F.3d 782, 789 (7th Cir. 2006). Statutes of
limitations in federal civil cases, unless otherwise
specified by Congress, begin to run upon discovery of the
injury from the alleged violation. Id. The defendants are
incorrect in suggesting that Klehr v. A. O. Smith Corp., 521
U.S. 179, 184 (1997), or any other case, has changed that
rule for antitrust. The fact that Zenith Radio Corp. v.
Hazeltine Research, Inc., 401 U.S. 321, 338 (1971), mentioned
only injury as the statute of limitations trigger in an
antitrust case in which there was no issue regarding
Nos. 12-1109, 12-1224                                     19

discovery does not imply the inapplicability of the dis-
covery rule to antitrust cases in which, as in this case,
the date of discovery might matter.
  The defendants argue that because the antitrust
laws specify treble damages for violations, prospective
plaintiffs should not be allowed to sit on their hands
after sustaining antitrust injury, in order to run up
their damages. But they aren’t allowed to sit on their
hands; the discovery rule requires diligence. Merck & Co.
v. Reynolds, 130 S. Ct. 1784, 1793-94 (2010); Cathedral of
Joy Baptist Church v. Village of Hazel Crest, 22 F.3d 713,
717 (7th Cir. 1994); SEC v. Gabelli, 653 F.3d 49, 59 (2d Cir.
2011). And punitive damages, whether in the form of
trebling compensatory damages or in other forms, are
available for violations of a number of different federal
statutes, to all of which, as far as we know, the dis-
covery rule applies. We can’t think of any reason to treat
antitrust statutes differently.
  Nevertheless, for the reasons discussed earlier, the
judgment of the district court is
                                                  A FFIRMED.




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