(Slip Opinion)              OCTOBER TERM, 2010                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 

, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

 MATRIXX INITIATIVES, INC., ET AL. v. SIRACUSANO
                    ET AL.

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
                  THE NINTH CIRCUIT

   No. 09–1156. Argued January 10, 2011—Decided March 22, 2011
Respondents filed this securities fraud class action, alleging that peti
  tioners (hereinafter Matrixx) violated §10(b) of the Securities Ex
  change Act of 1934 and Securities and Exchange Commission Rule
  10b–5 by failing to disclose reports of a possible link between Ma
  trixx’s leading product, Zicam Cold Remedy, and loss of smell (anos
  mia), rendering statements made by Matrixx misleading. Matrixx
  moved to dismiss the complaint, arguing that respondents had not
  pleaded the element of a material misstatement or omission and the
  element of scienter. The District Court granted the motion, but the
  Ninth Circuit reversed. It held that the District Court erred in re
  quiring an allegation of statistical significance to establish material
  ity, concluding instead that the complaint adequately alleged infor
  mation linking Zicam and anosmia that would have been significant
  to a reasonable investor. It also held that Matrixx’s withholding of
  information about reports of adverse effects and about pending law
  suits by Zicam users gave rise to a strong inference of scienter.
Held: Respondents have stated a claim under §10(b) and Rule 10b–5.
 Pp. 8–22.
    (a) To prevail on their claim, respondents must prove, as relevant
 here, a material misrepresentation or omission by Matrixx and sci
 enter. See Stoneridge Investment Partners, LLC v. Scientific-Atlanta,
 Inc., 

, 157. Matrixx contends that they failed to plead
 these required elements because they did not allege that the reports
 Matrixx received reflected statistically significant evidence that Zi
 cam caused anosmia. Pp. 8–9.
    (b) Respondents have adequately pleaded materiality. Pp. 9–19.
      (1) Under Basic Inc. v. Levinson, 

, §10(b)’s material
2            MATRIXX INITIATIVES, INC. v. SIRACUSANO

                                  Syllabus

    ity requirement is satisfied when there is “ ‘a substantial likelihood
    that the disclosure of the omitted fact would have been viewed by the
    reasonable investor as having significantly altered the “total mix” of
    information made available.’ ” 

The Court declined to
    adopt a bright-line rule for determining materiality in Basic, observ
    ing that “[a]ny approach that designates a single fact or occurrence as
    always determinative of an inherently fact-specific finding such as
    materiality, must necessarily be overinclusive or underinclusive.”
    

Here, Matrixx’s bright-line rule—that adverse event re
    ports regarding a pharmaceutical company’s products are not mate
    rial absent a sufficient number of such reports to establish a statisti
    cally significant risk that the product is causing the events—would
    “artificially exclud[e]” information that “would otherwise be consid
    ered significant to [a reasonable investor’s] trading decision.” 

statistical significance is the only reliable in
    dication of causation is flawed. Both medical experts and the Food
    and Drug Administration rely on evidence other than statistically
    significant data to establish an inference of causation. It thus stands
    to reason that reasonable investors would act on such evidence. Be
    cause adverse reports can take many forms, assessing their material
    ity is a fact-specific inquiry, requiring consideration of their source,
    content, and context. The question is whether a reasonable investor
    would have viewed the nondisclosed information “ ‘as having signifi
    cantly altered the “total mix” of information made available.’ ” 

Something more than the mere existence of adverse event re
    ports is needed to satisfy that standard, but that something more is
    not limited to statistical significance and can come from the source,
    content, and context of the reports. Pp. 9–16.
         (2) Applying Basic’s “total mix” standard here, respondents ade
    quately pleaded materiality. The complaint’s allegations suffice to
    “raise a reasonable expectation that discovery will reveal evidence”
    satisfying the materiality requirement, Bell Atlantic Corp. v.
    Twombly, 

, 556, and to “allo[w] the court to draw the
    reasonable inference that the defendant is liable,” Ashcroft v. Iqbal,
    556 U. S. ___, ___. Assuming the complaint’s allegations to be true,
    Matrixx received reports from medical experts and researchers that
    plausibly indicated a reliable causal link between Zicam and anos
    mia. Consumers likely would have viewed Zicam’s risk as substan
    tially outweighing its benefit. Viewing the complaint’s allegations as
    a whole, the complaint alleges facts suggesting a significant risk to
    the commercial viability of Matrixx’s leading product. It is substan
    tially likely that a reasonable investor would have viewed this infor
    mation “ ‘as having significantly altered the “total mix” of informa
    tion made available.’ ”       

.     Assuming the
                     Cite as: 563 U. S. ____ (2011)                      3

                                Syllabus

  complaint’s allegations to be true, Matrixx told the market that reve
  nues were going to rise 50 and then 80 percent when it had informa
  tion indicating a significant risk to its leading revenue-generating
  product. It also publicly dismissed reports linking Zicam and anos
  mia and stated that zinc gluconate’s safety was well established,
  when it had evidence of a biological link between Zicam’s key ingre
  dient and anosmia and had conducted no studies to disprove that
  link. Pp. 16–19.
     (c) Respondents have also adequately pleaded scienter, “ ‘a mental
  state embracing intent to deceive, manipulate, or defraud,’ ” Tellabs,
  Inc. v. Makor Issues & Rights, Ltd., 

, 319. This Court
  assumes, without deciding, that the scienter requirement may be sat
  isfied by a showing of deliberate recklessness. Under the Private Se
  curities Litigation Reform Act of 1995, a complaint adequately pleads
  scienter “only if a reasonable person would deem the inference of sci
  enter cogent and at least as compelling as any opposing inference one
  could draw from the facts alleged.” 

Matrixx’s proposed
  bright-line rule requiring an allegation of statistical significance to
  establish a strong inference of scienter is once again flawed. The
  complaint’s allegations, “taken collectively,” give rise to a “cogent and
  compelling” inference that Matrixx elected not to disclose adverse
  event reports not because it believed they were meaningless but be
  cause it understood their likely effect on the market. 

324.
  “[A] reasonable person” would deem the inference that Matrixx acted
  with deliberate recklessness “at least as compelling as any [plausible]
  opposing inference.” 

Pp. 19–22.

, affirmed.

  SOTOMAYOR, J., delivered the opinion for a unanimous Court.
                        Cite as: 563 U. S. ____ (2011)                              1

                             Opinion of the Court

     NOTICE: This opinion is subject to formal revision before publication in the
     preliminary print of the United States Reports. Readers are requested to
     notify the Reporter of Decisions, Supreme Court of the United States, Wash­
     ington, D. C. 20543, of any typographical or other formal errors, in order
     that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                   _________________

                                   No. 09–1156
                                   _________________


MATRIXX INITIATIVES, INC., ET AL., PETITIONERS v.

          JAMES SIRACUSANO ET AL. 

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

            APPEALS FOR THE NINTH CIRCUIT

                                [March 22, 2011] 


   JUSTICE SOTOMAYOR delivered the opinion of the Court.
   This case presents the question whether a plaintiff can
state a claim for securities fraud under §10(b) of the Secu­
rities Exchange Act of 1934, 48 Stat. 891, as amended, 

. §78j(b), and Securities and Exchange Commission
(SEC) Rule 10b–5, 17 CFR §240.10b–5 (2010), based on a
pharmaceutical company’s failure to disclose reports of
adverse events associated with a product if the reports do
not disclose a statistically significant number of adverse
events. Respondents, plaintiffs in a securities fraud class
action, allege that petitioners, Matrixx Initiatives, Inc.,
and three of its executives (collectively Matrixx), failed to
disclose reports of a possible link between its leading
product, a cold remedy, and loss of smell, rendering state­
ments made by Matrixx misleading. Matrixx contends
that respondents’ complaint does not adequately allege
that Matrixx made a material representation or omission
or that it acted with scienter because the complaint does
not allege that Matrixx knew of a statistically significant
number of adverse events requiring disclosure. We con­
clude that the materiality of adverse event reports cannot
2         MATRIXX INITIATIVES, INC. v. SIRACUSANO

                        Opinion of the Court

be reduced to a bright-line rule. Although in many cases
reasonable investors would not consider reports of adverse
events to be material information, respondents have al­
leged facts plausibly suggesting that reasonable investors
would have viewed these particular reports as material.
Respondents have also alleged facts “giving rise to a
strong inference” that Matrixx “acted with the required
state of mind.” 

. A. §78u–4(b)(2)(A) (Feb. 2011
Supp.). We therefore hold, in agreement with the Court of
Appeals for the Ninth Circuit, that respondents have
stated a claim under §10(b) and Rule 10b–5.
                             I

                             A

   Through a wholly owned subsidiary, Matrixx develops,
manufactures, and markets over-the-counter pharmaceu­
tical products. Its core brand of products is called Zicam.
All of the products sold under the name Zicam are used to
treat the common cold and associated symptoms. At the
time of the events in question, one of Matrixx’s products
was Zicam Cold Remedy, which came in several forms
including nasal spray and gel. The active ingredient in
Zicam Cold Remedy was zinc gluconate. Respondents
allege that Zicam Cold Remedy accounted for approxi­
mately 70 percent of Matrixx’s sales.
   Respondents initiated this securities fraud class action
against Matrixx on behalf of individuals who purchased
Matrixx securities between October 22, 2003, and Febru­
ary 6, 2004.1 The action principally arises out of state­
ments that Matrixx made during the class period relating
to revenues and product safety. Respondents claim that
Matrixx’s statements were misleading in light of reports
that Matrixx had received, but did not disclose, about

——————
 1 According to the complaint, Matrixx securities were traded on the

NASDAQ National Market. App. 99a.
                 Cite as: 563 U. S. ____ (2011)           3

                     Opinion of the Court

consumers who had lost their sense of smell (a condition
called anosmia) after using Zicam Cold Remedy. Respon­
dents’ consolidated amended complaint alleges the follow­
ing facts, which the courts below properly assumed to be
true. See Ashcroft v. Iqbal, 556 U. S. ___, ___ (2009) (slip
op., at 14).
  In 1999, Dr. Alan Hirsch, neurological director of the
Smell & Taste Treatment and Research Foundation, Ltd.,
called Matrixx’s customer service line after discovering a
possible link between Zicam nasal gel and a loss of smell
“in a cluster of his patients.” App. 67a–68a. Dr. Hirsch
told a Matrixx employee that “previous studies had dem­
onstrated that intranasal application of zinc could be
problematic.” 

He also told the employee about
at least one of his patients who did not have a cold and
who developed anosmia after using Zicam.
  In September 2002, Timothy Clarot, Matrixx’s vice
president for research and development, called Miriam
Linschoten, Ph.D., at the University of Colorado Health
Sciences Center after receiving a complaint from a per­
son Linschoten was treating who had lost her sense of
smell after using Zicam. Clarot informed Linschoten that
Matrixx had received similar complaints from other cus­
tomers. Linschoten drew Clarot’s attention to “previous
studies linking zinc sulfate to loss of smell.” 

the impression that he had not heard of the
studies. She asked Clarot whether Matrixx had done any
studies of its own; he responded that it had not but that it
had hired a consultant to review the product. Soon there­
after, Linschoten sent Clarot abstracts of the studies she
had mentioned. Research from the 1930’s and 1980’s had
confirmed “[z]inc’s toxicity.” 

Clarot called
Linschoten to ask whether she would be willing to partici­
pate in animal studies that Matrixx was planning, but she
declined because her focus was human research.
  By September 2003, one of Linschoten’s colleagues at
4          MATRIXX INITIATIVES, INC. v. SIRACUSANO

                         Opinion of the Court

the University of Colorado, Dr. Bruce Jafek, had observed
10 patients suffering from anosmia after Zicam use.
Linschoten and Jafek planned to present their findings at
a meeting of the American Rhinologic Society in a poster
presentation entitled “Zicam® Induced Anosmia.” 

omitted). The American Rhi­
nologic Society posted their abstract in advance of the
meeting. The presentation described in detail a 55-year­
old man with previously normal taste and smell who
experienced severe burning in his nose, followed immedi­
ately by a loss of smell, after using Zicam. It also reported
10 other Zicam users with similar symptoms.
   Matrixx learned of the doctors’ planned presentation.
Clarot sent a letter to Dr. Jafek warning him that he did
not have permission to use Matrixx’s name or the names
of its products. Dr. Jafek deleted the references to Zicam
in the poster before presenting it to the American Rhi­
nologic Society.
   The following month, two plaintiffs commenced a prod­
uct liability lawsuit against Matrixx alleging that Zicam
had damaged their sense of smell. By the end of the class
period on February 6, 2004, nine plaintiffs had filed four
lawsuits.
   Respondents allege that Matrixx made a series of public
statements that were misleading in light of the foregoing
information. In October 2003, after they had learned of
Dr. Jafek’s study and after Dr. Jafek had presented his
findings to the American Rhinologic Society, Matrixx
stated that Zicam was “ ‘poised for growth in the upcoming
cough and cold season’ ” and that the company had “ ‘very
strong momentum.’ ”2 

Matrixx further
——————
  2 At oral argument, counsel for the United States, which submitted an

amicus curiae brief in support of respondents, suggested that some of
these statements might qualify as nonactionable “puffery.” Tr. of Oral
Arg. 51–52. This question is not before us, as Matrixx has not ad­
vanced such an argument.
                     Cite as: 563 U. S. ____ (2011)                     5

                          Opinion of the Court

expressed its expectation that revenues would “ ‘be up in
excess of 50% and that earnings, per share for the full year
[would] be in the 25 to 30 cent range.’ ” 

In
January 2004, Matrixx raised its revenue guidance, pre­
dicting an increase in revenues of 80 percent and earnings
per share in the 33-to-38-cent range.
   In its Form 10–Q filed with the SEC in November 2003,
Zicam warned of the potential “ ‘material adverse effect’ ”
that could result from product liability claims, “ ‘whether
or not proven to be valid.’ ” 

It stated that
product liability actions could materially affect Matrixx’s
“ ‘product branding and goodwill,’ ” leading to reduced
customer acceptance.3 

It did not disclose,
however, that two plaintiffs had already sued Matrixx for
allegedly causing them to lose their sense of smell.
   On January 30, 2004, Dow Jones Newswires reported
that the Food and Drug Administration (FDA) was “ ‘look­
ing into complaints that an over-the-counter common-cold
medicine manufactured by a unit of Matrixx Initiatives,
Inc. (MTXX) may be causing some users to lose their sense
of smell’ ” in light of at least three product liability law­
suits. 

Matrixx’s stock fell from $13.55 to
$11.97 per share after the report. In response, on Febru­
ary 2, Matrixx issued a press release that stated:
       “All Zicam products are manufactured and mar­
     keted according to FDA guidelines for homeopathic
     medicine. Our primary concern is the health and
     safety of our customers and the distribution of fac-
     tual information about our products. Matrixx believes
     statements alleging that intranasal Zicam products
     caused anosmia (loss of smell) are completely un­
——————
  3 Respondents    also allege that Matrixx falsely reported its financial
results in the Form 10–Q by failing to reserve for or disclose potential
liability, in violation of Generally Accepted Accounting Principles. The
Court of Appeals did not rely on these allegations.
6        MATRIXX INITIATIVES, INC. v. SIRACUSANO

                     Opinion of the Court

    founded and misleading.
      “In no clinical trial of intranasal zinc gluconate gel
    products has there been a single report of lost or di­
    minished olfactory function (sense of smell). Rather,
    the safety and efficacy of zinc gluconate for the treat­
    ment of symptoms related to the common cold have
    been well established in two double-blind, placebo­
    controlled, randomized clinical trials. In fact, in nei­
    ther study were there any reports of anosmia related
    to the use of this compound. The overall incidence of
    adverse events associated with zinc gluconate was ex­
    tremely low, with no statistically significant difference
    between the adverse event rates for the treated and
    placebo subsets.
      “A multitude of environmental and biologic influ­
    ences are known to affect the sense of smell. Chief
    among them is the common cold. As a result, the
    population most likely to use cold remedy products is
    already at increased risk of developing anosmia.
    Other common causes of olfactory dysfunction include
    age, nasal and sinus infections, head trauma, ana­
    tomical obstructions, and environmental irritants.”
    

(internal quotation marks omitted).
The day after Matrixx issued this press release, its stock
price bounced back to $13.40 per share.
  On February 6, 2004, the end of the class period, Good
Morning America, a nationally broadcast morning news
program, highlighted Dr. Jafek’s findings. (The complaint
does not allege that Matrixx learned of the news story
before its broadcast.) The program reported that Dr. Jafek
had discovered more than a dozen patients suffering from
anosmia after using Zicam. It also noted that four law­
suits had been filed against Matrixx. The price of Matrixx
stock plummeted to $9.94 per share that same day. Zicam
again issued a press release largely repeating its February
                 Cite as: 563 U. S. ____ (2011)           7

                     Opinion of the Court

2 statement.
   On February 19, 2004, Matrixx filed a Form 8–K with
the SEC stating that it had “ ‘convened a two-day meeting
of physicians and scientists to review current information
on smell disorders’ ” in response to Dr. Jafek’s presenta­
tion. 

According to the Form 8–K, “ ‘In the
opinion of the panel, there is insufficient scientific evi­
dence at this time to determine if zinc gluconate, when
used as recommended, affects a person’s ability to smell.’ ”

later, a reporter quoted Matrixx as
stating that it would begin conducting “ ‘animal and hu­
man studies to further characterize these post-marketing
complaints.’ ” 

   On the basis of these allegations, respondents claimed
that Matrixx violated §10(b) of the Securities Exchange
Act and SEC Rule 10b–5 by making untrue statements of
fact and failing to disclose material facts necessary to
make the statements not misleading in an effort to main­
tain artificially high prices for Matrixx securities.
                              B
   Matrixx moved to dismiss respondents’ complaint, argu­
ing that they had failed to plead the elements of a mate­
rial misstatement or omission and scienter. The District
Court granted the motion to dismiss. Relying on In re
Carter-Wallace, Inc., Securities Litigation, 

(CA2 2000), it held that respondents had not alleged a
“statistically significant correlation between the use of
Zicam and anosmia so as to make failure to public[ly]
disclose complaints and the University of Colorado study a
material omission.” App. to Pet. for Cert. 50a. The Dis­
trict Court similarly agreed that respondents had not
stated with particularity facts giving rise to a strong
inference of scienter. See 

. A. §78u–4(b)(2)(A)
(Feb. 2011 Supp.). It noted that the complaint failed to
allege that Matrixx disbelieved its statements about Zi­
8        MATRIXX INITIATIVES, INC. v. SIRACUSANO

                     Opinion of the Court

cam’s safety or that any of the defendants profited or
attempted to profit from Matrixx’s public statements.
App. to Pet. for Cert. 52a.
   The Court of Appeals reversed. 

(CA9
2009). Noting that “ ‘[t]he determination [of materiality]
requires delicate assessments of the inferences a “reason­
able shareholder” would draw from a given set of facts and
the significance of those inferences to him,’ ” 

(quoting Basic Inc. v. Levinson, 

, 236 (1988);
some internal quotation marks omitted; alterations in
original), the Court of Appeals held that the District Court
had erred in requiring an allegation of statistical signifi­
cance to establish materiality. It concluded, to the con­
trary, that the complaint adequately alleged “information
regarding the possible link between Zicam and anosmia”
that would have been significant to a reasonable 

, 1180. Turning to scienter, the Court of
Appeals concluded that “[w]ithholding reports of adverse
effects of and lawsuits concerning the product responsible
for the company’s remarkable sales increase is ‘an extreme
departure from the standards of ordinary care,’ ” giving
rise to a strong inference of scienter. 

   We granted certiorari, 560 U. S. ___ (2010), and we now
affirm.
                             II
   Section 10(b) of the Securities Exchange Act makes it
unlawful for any person to “use or employ, in connection
with the purchase or sale of any security . . . any manipu­
lative or deceptive device or contrivance in contravention
of such rules and regulations as the Commission may
prescribe as necessary or appropriate in the public interest
or for the protection of investors.” 

. §78j(b).
SEC Rule 10b–5 implements this provision by making
it unlawful to, among other things, “make any untrue
statement of a material fact or to omit to state a material
                     Cite as: 563 U. S. ____ (2011)                   9

                         Opinion of the Court

fact necessary in order to make the statements made, in
the light of the circumstances under which they were
made, not misleading.” 17 CFR §240.10b–5(b). We have
implied a private cause of action from the text and pur­
pose of §10(b). See Tellabs, Inc. v. Makor Issues & Rights,
Ltd., 

, 318 (2007).
  To prevail on their claim that Matrixx made material
misrepresentations or omissions in violation of §10(b) and
Rule 10b–5, respondents must prove “(1) a material mis­
representation or omission by the defendant; (2) scienter;
(3) a connection between the misrepresentation or omis­
sion and the purchase or sale of a security; (4) reliance
upon the misrepresentation or omission; (5) economic loss;
and (6) loss causation.” Stoneridge Investment Partners,
LLC v. Scientific-Atlanta, Inc., 

, 157 (2008).
Matrixx contends that respondents have failed to plead
both the element of a material misrepresentation or omis­
sion and the element of scienter because they have not
alleged that the reports received by Matrixx reflected
statistically significant evidence that Zicam caused anos­
mia. We disagree.
                            A
   We first consider Matrixx’s argument that “adverse
event reports that do not reveal a statistically significant
increased risk of adverse events from product use are not
material information.” Brief for Petitioners 17 (capitaliza­
tion omitted).
                              1
  To prevail on a §10(b) claim, a plaintiff must show that
the defendant made a statement that was “misleading as
to a material fact.”4 

. In Basic, we
——————
   4 Under the Private Securities Litigation Reform Act of 1995

(PSLRA), when a plaintiff’s claim is based on alleged misrepresenta­
tions or omissions of a material fact, “the complaint shall specify each
10         MATRIXX INITIATIVES, INC. v. SIRACUSANO

                        Opinion of the Court

held that this materiality requirement is satisfied when
there is “ ‘a substantial likelihood that the disclosure of
the omitted fact would have been viewed by the reasonable
investor as having significantly altered the “total mix” of
information made available.’ ” 

(quoting
TSC Industries, Inc. v. Northway, Inc., 

, 449
(1976)). We were “careful not to set too low a standard of
materiality,” for fear that management would “ ‘bury
the shareholders in an avalanche of trivial information.’ 

(quoting TSC 

–449).
  Basic involved a claim that the defendant had made
misleading statements denying that it was engaged in
merger negotiations when it was, in fact, conducting pre­
liminary negotiations. 

–229. The
defendant urged a bright-line rule that preliminary
merger negotiations are material only once the parties to
the negotiations reach an agreement in principle. 

We observed that “[a]ny approach that desig­
nates a single fact or occurrence as always determinative
of an inherently fact-specific finding such as materiality,
must necessarily be overinclusive or underinclusive.” 

We thus rejected the defendant’s proposed rule,
explaining that it would “artificially exclud[e] from the
definition of materiality information concerning merger
discussions, which would otherwise be considered sig-
nificant to the trading decision of a reasonable investor.”

in Basic, Matrixx urges us to adopt a
bright-line rule that reports of adverse events5 associated
——————
statement alleged to have been misleading, [and] the reason or reasons
why the statement is misleading.” 

. §78u–4(b)(1).
  5 The FDA defines an “[a]dverse drug experience” as “[a]ny adverse

event associated with the use of a drug in humans, whether or not
considered drug related.” 21 CFR §314.80(a) (2010). Federal law
imposes certain obligations on pharmaceutical manufacturers to report
                      Cite as: 563 U. S. ____ (2011)                      11

                           Opinion of the Court

with a pharmaceutical company’s products cannot be
material absent a sufficient number of such reports to
establish a statistically significant risk that the product is
in fact causing the events.6 Absent statistical significance,
Matrixx argues, adverse event reports provide only “anec­
dotal” evidence that “the user of a drug experienced an
adverse event at some point during or following the use
of that drug.” Brief for Petitioners 17. Accordingly,
it contends, reasonable investors would not consider such
reports relevant unless they are statistically significant
because only then do they “reflect a scientifically reliable
basis for inferring a potential causal link between product
use and the adverse event.” 

   As in Basic, Matrixx’s categorical rule would “artificially
exclud[e]” information that “would otherwise be consid­
ered significant to the trading decision of a reasonable

. Matrixx’s argument rests on
the premise that statistical significance is the only reliable
indication of causation. This premise is flawed: As the
SEC points out, “medical researchers . . . consider multiple
——————
adverse events to the FDA. During the class period, manufacturers of
over-the-counter drugs such as Zicam Cold Remedy had no obligation to
report adverse events to the FDA. In 2006, Congress enacted legisla­
tion to require manufacturers of over-the-counter drugs to report any
“serious adverse event” to the FDA within 15 business days. See 

. §§379aa(b), (c).
   6 “A study that is statistically significant has results that are unlikely

to be the result of random error . . . .” Federal Judicial Center, Refer­
ence Manual on Scientific Evidence 354 (2d ed. 2000). To test for
significance, a researcher develops a “null hypothesis”—e.g., the asser­
tion that there is no relationship between Zicam use and anosmia. See

The researcher then calculates the probability of obtaining
the observed data (or more extreme data) if the null hypothesis is true
(called the p-value). 

evidence that the null
hypothesis is incorrect. See 

compares the
p-value to a preselected value called the significance level. 

If the p-value is below the preselected value, the difference is deemed
“significant.” 

12            MATRIXX INITIATIVES, INC. v. SIRACUSANO

                          Opinion of the Court

factors in assessing causation.” Brief for United States as
Amicus Curiae 12. Statistically significant data are not
always available. For example, when an adverse event is
subtle or rare, “an inability to obtain a data set of appro­
priate quality or quantity may preclude a finding of statis­
tical significance.” 

see also Brief for Medical
Researchers as Amici Curiae 11. Moreover, ethical con­
siderations may prohibit researchers from conducting
randomized clinical trials to confirm a suspected causal
link for the purpose of obtaining statistically significant
data. See 

   A lack of statistically significant data does not mean
that medical experts have no reliable basis for inferring a
causal link between a drug and adverse events. As Ma­
trixx itself concedes, medical experts rely on other evi­
dence to establish an inference of causation. See Brief for
Petitioners 44–45, n. 22.7 We note that courts frequently
permit expert testimony on causation based on evidence
other than statistical significance. See, e.g., Best v. Lowe’s
Home Centers, Inc., 

, 178 (CA6 2009); West
berry v. Gislaved Gummi AB, 

, 263–264 (CA4
1999) (citing cases); Wells v. Ortho Pharmaceutical Corp.,

, 744–745 (CA11 1986). We need not con­
sider whether the expert testimony was properly admitted
in those cases, and we do not attempt to define here what
constitutes reliable evidence of causation. It suffices to
——————
  7 Matrixx  and its amici list as relevant factors the strength of the
association between the drug and the adverse effects; a temporal
relationship between exposure and the adverse event; consistency
across studies; biological plausibility; consideration of alternative
explanations; specificity (i.e., whether the specific chemical is associ­
ated with the specific disease); the dose-response relationship; and the
clinical and pathological characteristics of the event. Brief for Petition­
ers 44–45, n. 22; Brief for Consumer Healthcare Products Assn. et al. as
Amici Curiae 12–13. These factors are similar to the factors the FDA
considers in taking action against pharmaceutical products. See infra,
at 13–14.
                       Cite as: 563 U. S. ____ (2011)      13

                             Opinion of the Court

note that, as these courts have recognized, “medical pro­
fessionals and researchers do not limit the data they
consider to the results of randomized clinical trials or to
statistically significant evidence.” Brief for Medical Re­
searchers as Amici Curiae 31.
   The FDA similarly does not limit the evidence it consid­
ers for purposes of assessing causation and taking regula­
tory action to statistically significant data. In assessing
the safety risk posed by a product, the FDA considers
factors such as “strength of the association,” “temporal
relationship of product use and the event,” “consistency of
findings across available data sources,” “evidence of a
dose-response for the effect,” “biologic plausibility,” “seri­
ousness of the event relative to the disease being treated,”
“potential to mitigate the risk in the population,” “feasibil­
ity of further study using observational or controlled
clinical study designs,” and “degree of benefit the product
provides, including availability of other therapies.”8 FDA,
Guidance for Industry: Good Pharmacovigilance Prac-
tices and Pharmacoepidemiologic Assessment 18 (2005)
(capitalization omitted), http://www.fda.gov/downloads/
RegulatingInformation/Guidances/UCM126834.pdf (all In­
ternet materials as visited Mar. 17, 2011, and available in
Clerk of Court’s case file); see also Brief for United States
as Amicus Curiae 19–20 (same); FDA, The Clinical Im-
pact of Adverse Event Reporting 6 (1996) (similar),
http://www.fda.gov/downloads/safety/MedWatch/UCM1685
05.pdf. It “does not apply any single metric for determin­
ing when additional inquiry or action is necessary, and it
certainly does not insist upon ‘statistical significance.’ ”
Brief for United States as Amicus Curiae 19.
   Not only does the FDA rely on a wide range of evidence
of causation, it sometimes acts on the basis of evidence
that suggests, but does not prove, causation. For example,
——————
 8 See   also n. 

.
14         MATRIXX INITIATIVES, INC. v. SIRACUSANO

                         Opinion of the Court

the FDA requires manufacturers of over-the-counter drugs
to revise their labeling “to include a warning as soon as
there is reasonable evidence of an association of a serious
hazard with a drug; a causal relationship need not have
been proved.” 21 CFR §201.80(e). More generally, the
FDA may make regulatory decisions against drugs based
on postmarketing evidence that gives rise to only a suspi­
cion of causation. See FDA, The Clinical Impact of Ad­
verse Event 

(“[A]chieving certain
proof of causality through postmarketing surveillance is
unusual. Attaining a prominent degree of suspicion is
much more likely, and may be considered a sufficient basis
for regulatory decisions” (footnote omitted)).9
  This case proves the point. In 2009, the FDA issued a
warning letter to Matrixx stating that “[a] significant and
growing body of evidence substantiates that the Zicam
Cold Remedy intranasal products may pose a serious risk
to consumers who use them.” App. 270a. The letter cited
as evidence 130 reports of anosmia the FDA had received,
the fact that the FDA had received few reports of anosmia
associated with other intranasal cold remedies, and “evi­
dence in the published scientific literature that various
salts of zinc can damage olfactory function in animals and
——————
  9 See also GAO, M. Crosse et al., Drug Safety: Improvement Needed
in FDA’s Postmarket Decision-making and Oversight Process 7 (GAO–
06–402, 2006) (“If FDA has information that a drug on the market may
pose a significant health risk to consumers, it weighs the effect of the
adverse events against the benefit of the drug to determine what
actions, if any, are warranted. This decision-making process is complex
and encompasses many factors, such as the medical importance and
utility of the drug, the drug’s extent of usage, the severity of the
disease being treated, the drug’s efficacy in treating this disease,
and the availability of other drugs to treat the same disorder”),
http://www.gao.gov/new.items/d06402.pdf; Federal Judicial Center,
supra n. 6, at 33 (“[R]isk assessors may pay heed to any evidence that
points to a need for caution, rather than assess the likelihood that a
causal relationship in a specific case is more likely than not”).
                 Cite as: 563 U. S. ____ (2011)           15

                     Opinion of the Court

humans.” 

cite statistically significant
data.
   Given that medical professionals and regulators act on
the basis of evidence of causation that is not statistically
significant, it stands to reason that in certain cases rea­
sonable investors would as well. As Matrixx acknowl­
edges, adverse event reports “appear in many forms,
including direct complaints by users to manufacturers,
reports by doctors about reported or observed patient
reactions, more detailed case reports published by doctors
in medical journals, or larger scale published clinical
studies.” Brief for Petitioners 17. As a result, assessing
the materiality of adverse event reports is a “fact-specific”
inquiry, 

, that requires considera­
tion of the source, content, and context of the reports.
This is not to say that statistical significance (or the lack
thereof) is irrelevant—only that it is not dispositive of
every case.
   Application of Basic’s “total mix” standard does not
mean that pharmaceutical manufacturers must dis-
close all reports of adverse events. Adverse event reports
are daily events in the pharmaceutical industry; in
2009, the FDA entered nearly 500,000 such reports into
its reporting system, see FDA, Reports Received and
Reports Entered in AERS by Year (as of Mar. 31, 2010),
http://www.fda.gov/Drugs/GuidanceComplianceRegulatory
Information/Surveillance/AdverseDrugEffects/ucm070434.
htm. The fact that a user of a drug has suffered an
adverse event, standing alone, does not mean that
the drug caused that event. See FDA, Annual Adverse
Drug Experience Report: 1996, p. 2 (1997), http://drugand
devicelaw.net/Annual%20Adverse%20Drug%20Experience
%20Report%201996.pdf. The question remains whether a
reasonable investor would have viewed the nondisclosed
information “ ‘as having significantly altered the “total
mix” of information made available.’ ” 

        MATRIXX INITIATIVES, INC. v. SIRACUSANO

                          Opinion of the Court

232 (quoting TSC 

; emphasis
added). For the reasons just stated, the mere existence of
reports of adverse events—which says nothing in and of
itself about whether the drug is causing the adverse
events—will not satisfy this standard. Something more is
needed, but that something more is not limited to statisti­
cal significance and can come from “the source, content,
and context of the 

. This contextual
inquiry may reveal in some cases that reasonable inves­
tors would have viewed reports of adverse events as mate­
rial even though the reports did not provide statistically
significant evidence of a causal link.10
   Moreover, it bears emphasis that §10(b) and Rule 10b–
5(b) do not create an affirmative duty to disclose any and
all material information. Disclosure is required under
these provisions only when necessary “to make . . . state­
ments made, in the light of the circumstances under which
they were made, not misleading. 17 CFR §240.10b–5(b);
see also 

, n. 17 (“Silence, absent a
duty to disclose, is not misleading under Rule 10b–5”).
Even with respect to information that a reasonable inves­
tor might consider material, companies can control what
they have to disclose under these provisions by controlling
what they say to the market.
                            2
  Applying Basic’s “total mix” standard in this case, we
conclude that respondents have adequately pleaded mate­
riality. This is not a case about a handful of anecdotal
——————
10 We note that our conclusion accords with views of the SEC, as ex­

pressed in an amicus curiae brief filed in this case. See Brief for United
States as Amicus Curiae 11–12; see also TSC Industries, Inc. v. North
way, Inc., 

, 449, n. 10 (1976) (“[T]he SEC’s view of the
proper balance between the need to insure adequate disclosure and the
need to avoid the adverse consequences of setting too low a threshold
for civil liability is entitled to consideration”).
                     Cite as: 563 U. S. ____ (2011)                    17

                          Opinion of the Court

reports, as Matrixx suggests. Assuming the complaint’s
allegations to be true, as we must, Matrixx received in­
formation that plausibly indicated a reliable causal link
between Zicam and anosmia. That information included
reports from three medical professionals and researchers
about more than 10 patients who had lost their sense of
smell after using Zicam. Clarot told Linschoten that
Matrixx had received additional reports of anosmia. (In
addition, during the class period, nine plaintiffs com­
menced four product liability lawsuits against Matrixx
alleging a causal link between Zicam use and anosmia.)11
Further, Matrixx knew that Linschoten and Dr. Jafek had
presented their findings about a causal link between
Zicam and anosmia to a national medical conference de­
voted to treatment of diseases of the nose.12 Their presen­
tation described a patient who experienced severe burning
in his nose, followed immediately by a loss of smell, after
using Zicam—suggesting a temporal relationship between
Zicam use and anosmia.
  Critically, both Dr. Hirsch and Linschoten had also
drawn Matrixx’s attention to previous studies that had
demonstrated a biological causal link between intranasal
application of zinc and anosmia.13 Before his conversation
——————
  11 It is unclear whether these plaintiffs were the same individuals
whose symptoms were reported by the medical professionals.
  12 Matrixx contends that Dr. Jafek and Linschoten’s study was not

reliable because they did not sufficiently rule out the common cold as a
cause for their patients’ anosmia. We note that the complaint alleges
that, in one instance, a consumer who did not have a cold lost his sense
of smell after using Zicam. More importantly, to survive a motion to
dismiss, respondents need only allege “enough facts to state a claim to
relief that is plausible on its face.” Bell Atlantic Corp. v. Twombly, 

, 570 (2007). For all the reasons we state in the opinion,
respondents’ allegations plausibly suggest that Dr. Jafek and Linscho­
ten’s conclusions were based on reliable evidence of a causal link
between Zicam and anosmia.
  13 Matrixx contends that these studies are not reliable evidence of
18         MATRIXX INITIATIVES, INC. v. SIRACUSANO

                         Opinion of the Court

with Linschoten, Clarot, Matrixx’s vice president of re­
search and development, was seemingly unaware of these
studies, and the complaint suggests that, as of the class
period, Matrixx had not conducted any research of its own
relating to anosmia. See, e.g., App. 84a (referencing a
press report, issued after the end of the class period, not­
ing that Matrixx said it would begin conducting “ ‘animal
and human studies to further characterize these post­
marketing complaints’ ”). Accordingly, it can reasonably
be inferred from the complaint that Matrixx had no basis
for rejecting Dr. Jafek’s findings out of hand.
   We believe that these allegations suffice to “raise a
reasonable expectation that discovery will reveal evidence”
satisfying the materiality requirement, Bell Atlantic Corp.
v. Twombly, 

, 556 (2007), and to “allo[w] the
court to draw the reasonable inference that the defendant
is liable for the misconduct alleged,” Iqbal, 556 U. S., at
___ (slip op., at 14). The information provided to Matrixx
by medical experts revealed a plausible causal relation­
ship between Zicam Cold Remedy and anosmia. Consum­
ers likely would have viewed the risk associated with
Zicam (possible loss of smell) as substantially outweighing
the benefit of using the product (alleviating cold symp­
toms), particularly in light of the existence of many alter­
native products on the market. Importantly, Zicam Cold
Remedy allegedly accounted for 70 percent of Matrixx’s
sales. Viewing the allegations of the complaint as a whole,

——————
causation because the studies used zinc sulfate, whereas the active
ingredient in Matrixx is zinc gluconate. Respondents’ complaint,
however, alleges that the studies confirmed the toxicity of “zinc.” App.
68a. Matrixx further contends that studies relating to fish cannot
reliably prove causation with respect to humans. The complaint
references several studies, however, only one of which involved fish. In
any event, the existence of the studies suggests a plausible biological
link between zinc and anosmia, which, in combination with the other
allegations, is sufficient to survive a motion to dismiss.
                  Cite as: 563 U. S. ____ (2011)            19

                      Opinion of the Court

the complaint alleges facts suggesting a significant risk to
the commercial viability of Matrixx’s leading product.
    It is substantially likely that a reasonable investor
would have viewed this information “ ‘as having signifi­
cantly altered the “total mix” of information made avail­
able.’ ” 

(quoting TSC 

). Matrixx told the market that revenues
were going to rise 50 and then 80 percent. Assuming the
complaint’s allegations to be true, however, Matrixx had
information indicating a significant risk to its leading
revenue-generating product. Matrixx also stated that
reports indicating that Zicam caused anosmia were “ ‘com­
pletely unfounded and misleading’ ” and that “ ‘the safety
and efficacy of zinc gluconate for the treatment of symp­
toms related to the common cold have been well estab­
lished.’ ” App. 77a–78a. Importantly, however, Matrixx
had evidence of a biological link between Zicam’s key
ingredient and anosmia, and it had not conducted any
studies of its own to disprove that link. In fact, as Matrixx
later revealed, the scientific evidence at that time was
“ ‘insufficient . . . to determine if zinc gluconate, when used
as recommended, affects a person’s ability to smell.’ ” 

    Assuming the facts to be true, these were material facts
“necessary in order to make the statements made, in the
light of the circumstances under which they were made,
not misleading.” 17 CFR §240.10b–5(b). We therefore
affirm the Court of Appeals’ holding that respondents
adequately pleaded the element of a material misrepre­
sentation or omission.
                             B
  Matrixx also argues that respondents failed to allege
facts plausibly suggesting that it acted with the required
level of scienter. “To establish liability under §10(b) and
Rule 10b–5, a private plaintiff must prove that the defen­
20           MATRIXX INITIATIVES, INC. v. SIRACUSANO

                        Opinion of the Court

dant acted with scienter, ‘a mental state embracing intent
to deceive, manipulate, or defraud.’ ” 

(quoting Ernst & Ernst v. Hochfelder, 

,
193–194, and n. 12 (1976)). We have not decided whether
recklessness suffices to fulfill the scienter requirement.
See 

, n. 3. Because Matrixx does
not challenge the Court of Appeals’ holding that the
scienter requirement may be satisfied by a showing of
“deliberate recklessness,” 

(internal
quotation marks omitted), we assume, without deciding,
that the standard applied by the Court of Appeals is suffi­
cient to establish scienter.14
   Under the PSLRA, a plaintiff must “state with par­
ticularity facts giving rise to a strong inference that the
defendant acted with the required state of mind.” 

. A. §78u–4(b)(2)(A) (Feb. 2011 Supp.). This stan­
dard requires courts to take into account “plausible oppos­
ing inferences.” 

. A complaint
adequately pleads scienter under the PSLRA “only if a
reasonable person would deem the inference of scienter
cogent and at least as compelling as any opposing infer­
ence one could draw from the facts alleged.” 

In making this determination, the court must review “all
the allegations holistically.” 

The absence of a
motive allegation, though relevant, is not dispositive. 

   Matrixx argues, in summary fashion, that because
respondents do not allege that it knew of statistically
significant evidence of causation, there is no basis to
consider the inference that it acted recklessly or know­
ingly to be at least as compelling as the alternative infer­

——————
  14 Under the PSLRA, if the alleged misstatement or omission is a
“forward-looking statement,” the required level of scienter is “actual
knowledge.” 

. §78u–5(c)(1)(B). Matrixx has not argued that
the statements or omissions here are “forward-looking statement[s].”
                      Cite as: 563 U. S. ____ (2011)                    21

                          Opinion of the Court

ences. “Rather,” it argues, “the most obvious inference is
that petitioners did not disclose the [reports] simply be­
cause petitioners believed they were far too few . . . to
indicate anything meaningful about adverse reactions to
use of Zicam.” Brief for Petitioners 49. Matrixx’s pro­
posed bright-line rule requiring an allegation of statistical
significance to establish a strong inference of scienter is
just as flawed as its approach to materiality.
   The inference that Matrixx acted recklessly (or inten­
tionally, for that matter) is at least as compelling, if not
more compelling, than the inference that it simply thought
the reports did not indicate anything meaningful about
adverse reactions. According to the complaint, Matrixx
was sufficiently concerned about the information it re­
ceived that it informed Linschoten that it had hired a
consultant to review the product, asked Linschoten to
participate in animal studies, and convened a panel of
physicians and scientists in response to Dr. Jafek’s pres­
entation. It successfully prevented Dr. Jafek from using
Zicam’s name in his presentation on the ground that he
needed Matrixx’s permission to do so. Most significantly,
Matrixx issued a press release that suggested that studies
had confirmed that Zicam does not cause anosmia when,
in fact, it had not conducted any studies relating to anos­
mia and the scientific evidence at that time, according to
the panel of scientists, was insufficient to determine
whether Zicam did or did not cause anosmia.15

——————
   15 One of Matrixx’s amici argues that “the most cogent inference re­

garding Matrixx’s state of mind is that it delayed releasing information
regarding anosmia complaints in order to provide itself an opportunity
to carefully review all evidence regarding any link between Zicam and
anosmia.” Brief for Washington Legal Foundation as Amicus Curiae
26. We do not doubt that this may be the most cogent inference in some
cases. Here, however, the misleading nature of Matrixx’s press release
is sufficient to render the inference of scienter at least as compelling as
the inference suggested by amicus.
22       MATRIXX INITIATIVES, INC. v. SIRACUSANO

                     Opinion of the Court

  These allegations, “taken collectively,” give rise to a
“cogent and compelling” inference that Matrixx elected not
to disclose the reports of adverse events not because it
believed they were meaningless but because it understood
their likely effect on the market. 

, 324. “[A] reasonable person” would deem the infer­
ence that Matrixx acted with deliberate recklessness (or
even intent) “at least as compelling as any opposing infer­
ence one could draw from the facts alleged.” 

We conclude, in agreement with the Court of Appeals, that
respondents have adequately pleaded scienter. Whether
respondents can ultimately prove their allegations and
establish scienter is an altogether different question.
                       *    *    *
 For the reasons stated, the judgment of the Court of
Appeals for the Ninth Circuit is
                                            Affirmed.