KRUPSKI v. COSTA CROCIERE S. P. A

(Slip Opinion) OCTOBER TERM, 2009 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., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

KRUPSKI v. COSTA CROCIERE S. P. A.

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR

THE ELEVENTH CIRCUIT

No. 09–337. Argued April 21, 2010—Decided June 7, 2010

Petitioner Krupski sought compensation for injuries she suffered on a

cruise ship. Her passenger ticket, which was issued by Costa Cruise

Lines, identified respondent Costa Crociere S. p. A. as the carrier; re

quired an injured party to submit to the carrier or its agent written

notice of a claim; required any lawsuit to be filed within one year of

the injury; and designated a specific Federal District Court as the ex

clusive forum for lawsuits such as Krupski’s. The front of the ticket

listed Costa Cruise’s Florida address and made references to “Costa

Cruises.” After Krupski’s attorney notified Costa Cruise of her

claims but did not reach a settlement, Krupski filed a diversity negli

gence action against Costa Cruise. Over the next several months—

after the limitations period had expired—Costa Cruise brought Costa

Crociere’s existence to Krupski’s attention three times, including in

its motion for summary judgment, in which it stated that Costa Cro

ciere was the proper defendant. Krupski responded and moved to

amend her complaint to add Costa Crociere as a defendant. The Dis

trict Court denied Costa Cruise’s summary judgment motion without

prejudice and granted Krupski leave to amend. After she served

Costa Crociere with an amended complaint, the court dismissed

Costa Cruise from the case. Thereafter, Costa Crociere—represented

by the same counsel as Costa Cruise—moved to dismiss, contending

that the amended complaint did not satisfy the requirements of Fed

eral Rule of Civil Procedure 15(c), which governs when an amended

pleading “relates back” to the date of a timely filed original pleading

and is thus timely even though it was filed outside an applicable limi

tations period. The Rule requires, inter alia, that within the Rule

4(m) 120-day period for service after a complaint is filed, the newly

named defendant “knew or should have known that the action would

2 KRUPSKI v. COSTA CROCIERE S. P. A.

Syllabus

have been brought against it, but for a mistake concerning the proper

party’s identity.” Rule 15(c)(1)(C)(ii). The District Court found this

condition fatal to Krupski’s attempt to relate back. It concluded that

she had not made a mistake about the proper party’s identity be

cause, although Costa Cruise had disclosed Costa Crociere’s role in

several court filings, she nonetheless delayed for months filing an

amended complaint. The Eleventh Circuit affirmed, finding that

Krupski either knew or should have known of Costa Crociere’s iden

tity as a potential party because she furnished the ticket identifying

it to her counsel well before the limitations period ended. It was

therefore appropriate to treat her as having chosen to sue one poten

tial party over another. Additionally, the court held that relation

back was not appropriate because of Krupski’s undue delay in seek

ing to amend the complaint.

Held: Relation back under Rule 15(c)(1)(C) depends on what the party

to be added knew or should have known, not on the amending party’s

knowledge or timeliness in seeking to amend the pleading. Pp. 7–18.

(a) The Rule’s text does not support the Eleventh Circuit’s decision

to rely on the plaintiff’s knowledge in denying relation back. The

question under Rule 15(c)(1)(C)(ii) is not whether Krupski knew or

should have known Costa Crociere’s identity as the proper defendant,

but whether Costa Crociere knew or should have known during the

Rule 4(m) period that it would have been named as the defendant but

for an error. The plaintiff’s information is relevant only if it bears on

the defendant’s understanding of whether the plaintiff made a mis

take regarding the proper party’s identity. It would be error to con

flate knowledge of a party’s existence with the absence of mistake.

That a plaintiff knows of a party’s existence does not preclude her

from making a mistake with respect to that party’s identity. Making

a deliberate choice to sue one party over another while understand

ing the factual and legal differences between the two parties may be

the antithesis of making a mistake, but that does not mean that any

time a plaintiff is aware of the existence of two parties and chooses to

sue the wrong one, the proper defendant could reasonably believe

that the plaintiff made no mistake. A plaintiff might know that the

prospective defendant exists but nonetheless choose to sue a different

defendant based on a misunderstanding about the proper party’s

identity. That kind of deliberate but mistaken choice should not fore

close a finding that Rule 15(c)(1)(C)(ii) has been satisfied. This read

ing is consistent with relation back’s purpose of balancing the defen

dant’s interests protected by the statute of limitations with the

preference of the Federal Rules of Civil Procedure in general, and

Rule 15 in particular, for resolving disputes on their merits. It is also

consistent with the history of Rule 15(c)(1)(C). And it is not fore

Cite as: 560 U. S. ____ (2010) 3

Syllabus

closed by Nelson v. Adams USA, Inc., 529 U. S. 460. Pp. 7–13.

(b) The Eleventh Circuit also erred in ruling that Krupski’s undue

delay in seeking to file, and in eventually filing, an amended com

plaint justified its denial of relation back under Rule 15(c)(1)(C). The

Rule plainly sets forth an exclusive list of requirements for relation

back, and the plaintiff’s diligence is not among them. Moreover, it

mandates relation back once its requirements are satisfied; it does

not leave that decision to the district court’s equitable discretion. Its

mandatory nature is particularly striking in contrast to the inquiry

under Rule 15(a), which gives a district court discretion to decide

whether to grant a motion to amend a pleading before trial. See

Foman v. Davis, 371 U. S. 178, 182. Rule 15(c)(1)(C) permits a court

to examine a plaintiff’s conduct during the Rule 4(m) period, but only

to the extent the plaintiff’s postfiling conduct informs the prospective

defendant’s understanding of whether the plaintiff initially made a

“mistake concerning the proper party’s identity.” The plaintiff’s post

filing conduct is otherwise immaterial to the relation-back question.

Pp. 13–15.

(c) Under these principles, the courts below erred in denying rela

tion back. Because the original complaint (of which Costa Crociere

had constructive notice) made clear that Krupski meant to sue the

company that “owned, operated, managed, supervised and controlled”

the ship on which she was injured and also indicated (mistakenly)

that Costa Cruise performed those roles, Costa Crociere should have

known that it avoided suit within the limitations period only because

of Krupski’s misunderstanding about which “Costa” entity was in

charge of the ship—clearly a “mistake concerning the proper party’s

identity.” That Krupski may have known the ticket’s contents does

not foreclose the possibility that she nonetheless misunderstood cru

cial facts regarding the two companies’ identities. Especially because

the face of the complaint plainly indicated such a misunderstanding,

respondent’s contention that it was entitled to think she made no

mistake is not persuasive. Moreover, respondent has articulated no

strategy that it could reasonably have thought Krupski was pursuing

in suing a defendant that was legally unable to provide relief. Noth

ing in Krupski’s conduct during the Rule 4(m) period suggests that

she failed to name Costa Crociere because of anything other than a

mistake. The interrelationship between Costa Cruise and Costa Cro

ciere and their similar names heighten the expectation that Costa

Crociere should suspect a mistake when Costa Cruise is named in a

complaint actually describing Costa Crociere’s activities. In addition,

Costa Crociere’s own actions contributed to passenger confusion over

“the proper party”: The front of the ticket advertises that “Costa

Cruises” has achieved a certification of quality without clarifying

4 KRUPSKI v. COSTA CROCIERE S. P. A.

Syllabus

which “Costa” company is meant. And as shown in similar lawsuits,

Costa Crociere is evidently well aware that the difference between it

and Costa Cruise can be confusing for passengers. Pp. 15–18.

330 Fed. Appx. 892, reversed and remanded.

SOTOMAYOR, J., delivered the opinion of the Court, in which ROBERTS,

C. J., and STEVENS, KENNEDY, THOMAS, GINSBURG, BREYER, and ALITO,

JJ., joined. SCALIA, J., filed an opinion concurring in part and concur

ring in the judgment.

Cite as: 560 U. S. ____ (2010) 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. 09–337

_________________

WANDA KRUPSKI, PETITIONER v. COSTA

CROCIERE S. P. A.

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

APPEALS FOR THE ELEVENTH CIRCUIT

[June 7, 2010]

JUSTICE SOTOMAYOR delivered the opinion of the Court.

Rule 15(c) of the Federal Rules of Civil Procedure gov

erns when an amended pleading “relates back” to the date

of a timely filed original pleading and is thus itself timely

even though it was filed outside an applicable statute of

limitations. Where an amended pleading changes a party

or a party’s name, the Rule requires, among other things,

that “the party to be brought in by amendment . . . knew

or should have known that the action would have been

brought against it, but for a mistake concerning the proper

party’s identity.” Rule 15(c)(1)(C). In this case, the Court

of Appeals held that Rule 15(c) was not satisfied because

the plaintiff knew or should have known of the proper

defendant before filing her original complaint. The court

also held that relation back was not appropriate because

the plaintiff had unduly delayed in seeking to amend. We

hold that relation back under Rule 15(c)(1)(C) depends on

what the party to be added knew or should have known,

not on the amending party’s knowledge or its timeliness in

seeking to amend the pleading. Accordingly, we reverse

the judgment of the Court of Appeals.

2 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

I

On February 21, 2007, petitioner, Wanda Krupski,

tripped over a cable and fractured her femur while she

was on board the cruise ship Costa Magica. Upon her

return home, she acquired counsel and began the process

of seeking compensation for her injuries. Krupski’s pas

senger ticket—which explained that it was the sole con

tract between each passenger and the carrier, App. to Pet.

for Cert. 37a—included a variety of requirements for

obtaining damages for an injury suffered on board one of

the carrier’s ships. The ticket identified the carrier as

“Costa Crociere S. p. A., an Italian corporation, and all

Vessels and other ships owned, chartered, operated,

marketed or provided by Costa Crociere, S. p. A., and

all officers, staff members, crew members, independ

ent contractors, medical providers, concessionaires, pi

lots, suppliers, agents and assigns onboard said Ves

sels, and the manufacturers of said Vessels and all

their component parts.” Id., at 27a.

The ticket required an injured party to submit “written

notice of the claim with full particulars . . . to the carrier

or its duly authorized agent within 185 days after the date

of injury.” Id., at 28a. The ticket further required any

lawsuit to be “filed within one year after the date of in

jury” and to be “served upon the carrier within 120 days

after filing.” Ibid. For cases arising from voyages depart

ing from or returning to a United States port in which the

amount in controversy exceeded $75,000, the ticket desig

nated the United States District Court for the Southern

District of Florida in Broward County, Florida, as the

exclusive forum for a lawsuit. Id., at 36a. The ticket

extended the “defenses, limitations and exceptions . . . that

may be invoked by the CARRIER” to “all persons who may

act on behalf of the CARRIER or on whose behalf the

CARRIER may act,” including “the CARRIER’s parents,

Cite as: 560 U. S. ____ (2010) 3

Opinion of the Court

subsidiaries, affiliates, successors, assigns, representa

tives, agents, employees, servants, concessionaires and

contractors” as well as “Costa Cruise Lines N. V.,” identi

fied as the “sales and marketing agent for the CARRIER

and the issuer of this Passage Ticket Contract.” Id., at

29a. The front of the ticket listed Costa Cruise Lines’

address in Florida and stated that an entity called “Costa

Cruises” was “the first cruise company in the world” to

obtain a certain certification of quality. Id., at 25a.

On July 2, 2007, Krupski’s counsel notified Costa Cruise

Lines of Krupski’s claims. App. 69–70. On July 9, 2007,

the claims administrator for Costa Cruise requested addi

tional information from Krupski “[i]n order to facilitate

our future attempts to achieve a pre-litigation settlement.”

App. to Pet. for Cert. 23a–24a. The parties were unable to

reach a settlement, however, and on February 1, 2008—

three weeks before the 1-year limitations period expired—

Krupski filed a negligence action against Costa Cruise,

invoking the diversity jurisdiction of the Federal District

Court for the Southern District of Florida. The complaint

alleged that Costa Cruise “owned, operated, managed,

supervised and controlled” the ship on which Krupski had

injured herself; that Costa Cruise had extended to its

passengers an invitation to enter onto the ship; and that

Costa Cruise owed Krupski a duty of care, which it

breached by failing to take steps that would have pre

vented her accident. App. 23–26. The complaint further

stated that venue was proper under the passenger ticket’s

forum selection clause and averred that, by the July 2007

notice of her claims, Krupski had complied with the

ticket’s presuit requirements. Id., at 23. Krupski served

Costa Cruise on February 4, 2008.

Over the next several months—after the limitations

period had expired—Costa Cruise brought Costa Croci

ere’s existence to Krupski’s attention three times. First,

on February 25, 2008, Costa Cruise filed its answer, as

4 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

serting that it was not the proper defendant, as it was

merely the North American sales and marketing agent for

Costa Crociere, which was the actual carrier and vessel

operator. Id., at 31. Second, on March 20, 2008, Costa

Cruise listed Costa Crociere as an interested party in its

corporate disclosure statement. App. to Pet. for Cert. 20a.

Finally, on May 6, 2008, Costa Cruise moved for summary

judgment, again stating that Costa Crociere was the

proper defendant. App. 5, 33–38.

On June 13, 2008, Krupski responded to Costa Cruise’s

motion for summary judgment, arguing for limited discov

ery to determine whether Costa Cruise should be dis

missed. According to Krupski, the following sources of

information led her to believe Costa Cruise was the re

sponsible party: The travel documents prominently identi

fied Costa Cruise and gave its Florida address; Costa

Cruise’s Web site listed Costa Cruise in Florida as the

United States office for the Italian company Costa Croci

ere; and the Web site of the Florida Department of State

listed Costa Cruise as the only “Costa” company registered

to do business in that State. Id., at 43–45, 56–59. Krup

ski also observed that Costa Cruise’s claims administrator

had responded to her claims notification without indicat

ing that Costa Cruise was not a responsible party. Id., at

45. With her response, Krupski simultaneously moved to

amend her complaint to add Costa Crociere as a defen

dant. Id., at 41–42, 52–54.

On July 2, 2008, after oral argument, the District Court

denied Costa Cruise’s motion for summary judgment

without prejudice and granted Krupski leave to amend,

ordering that Krupski effect proper service on Costa Cro

ciere by September 16, 2008. Id., at 71–72. Complying

with the court’s deadline, Krupski filed an amended com

plaint on July 11, 2008, and served Costa Crociere on

August 21, 2008. Id., at 73, 88–89. On that same date,

the District Court issued an order dismissing Costa Cruise

Cite as: 560 U. S. ____ (2010) 5

Opinion of the Court

from the case pursuant to the parties’ joint stipulation,

Krupski apparently having concluded that Costa Cruise

was correct that it bore no responsibility for her injuries.

Id., at 85–86.

Shortly thereafter, Costa Crociere—represented by the

same counsel who had represented Costa Cruise, compare

id., at 31, with id., at 100—moved to dismiss, contending

that the amended complaint did not relate back under

Rule 15(c) and was therefore untimely. The District Court

agreed. App. to Pet. for Cert. 8a–22a. Rule 15(c), the

court explained, imposes three requirements before an

amended complaint against a newly named defendant can

relate back to the original complaint. First, the claim

against the newly named defendant must have arisen “out

of the conduct, transaction, or occurrence set out—or

attempted to be set out—in the original pleading.” Fed.

Rules Civ. Proc. 15(c)(1)(B), (C). Second, “within the

period provided by Rule 4(m) for serving the summons and

complaint” (which is ordinarily 120 days from when the

complaint is filed, see Rule 4(m)), the newly named defen

dant must have “received such notice of the action that it

will not be prejudiced in defending on the merits.” Rule

15(c)(1)(C)(i). Finally, the plaintiff must show that, within

the Rule 4(m) period, the newly named defendant “knew

or should have known that the action would have been

brought against it, but for a mistake concerning the proper

party’s identity.” Rule 15(c)(1)(C)(ii).

The first two conditions posed no problem, the court

explained: The claim against Costa Crociere clearly in

volved the same occurrence as the original claim against

Costa Cruise, and Costa Crociere had constructive notice

of the action and had not shown that any unfair prejudice

would result from relation back. App. to Pet. for Cert.

14a–18a. But the court found the third condition fatal to

Krupski’s attempt to relate back, concluding that Krupski

had not made a mistake concerning the identity of the

6 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

proper party. Id., at 18a–21a. Relying on Eleventh Cir

cuit precedent, the court explained that the word “mis

take” should not be construed to encompass a deliberate

decision not to sue a party whose identity the plaintiff

knew before the statute of limitations had run. Because

Costa Cruise informed Krupski that Costa Crociere was

the proper defendant in its answer, corporate disclosure

statement, and motion for summary judgment, and yet

Krupski delayed for months in moving to amend and then

in filing an amended complaint, the court concluded that

Krupski knew of the proper defendant and made no

mistake.

The Eleventh Circuit affirmed in an unpublished per

curiam opinion. Krupski v. Costa Cruise Lines, N. V.,

LLC, 330 Fed. Appx. 892 (2009). Rather than relying on

the information contained in Costa Cruise’s filings, all of

which were made after the statute of limitations had

expired, as evidence that Krupski did not make a mistake,

the Court of Appeals noted that the relevant information

was located within Krupski’s passenger ticket, which she

had furnished to her counsel well before the end of the

limitations period. Because the ticket clearly identified

Costa Crociere as the carrier, the court stated, Krupski

either knew or should have known of Costa Crociere’s

identity as a potential party.1 It was therefore appropri

ate to treat Krupski as having chosen to sue one potential

party over another. Alternatively, even assuming that she

first learned of Costa Crociere’s identity as the correct

party from Costa Cruise’s answer, the Court of Appeals

——————

1 The Court of Appeals stated that it was “imput[ing]” knowledge to

Krupski. 330 Fed. Appx., at 895. Petitioner uses the terms “imputed

knowledge” and “constructive knowledge” interchangeably in her brief,

while respondent addresses only actual knowledge. Because we reject

the Court of Appeals’ focus on the plaintiff’s knowledge in the first

instance, see infra, at 8–13, the distinction among these types of

knowledge is not relevant to our resolution of this case.

Cite as: 560 U. S. ____ (2010) 7

Opinion of the Court

observed that Krupski waited 133 days from the time she

filed her original complaint to seek leave to amend and did

not file an amended complaint for another month after

that. In light of this delay, the Court of Appeals concluded

that the District Court did not abuse its discretion in

denying relation back.

We granted certiorari to resolve tension among the

Circuits over the breadth of Rule 15(c)(1)(C)(ii),2 558 U. S.

___ (2010), and we now reverse.

II

Under the Federal Rules of Civil Procedure, an amend

ment to a pleading relates back to the date of the original

pleading when:

“(A) the law that provides the applicable statute of

limitations allows relation back;

“(B) the amendment asserts a claim or defense that

arose out of the conduct, transaction, or occurrence set

out—or attempted to be set out—in the original plead

——————

2 See, e.g., Krupski v. Costa Cruise Lines, N. V., LLC, 330 Fed. Appx.

892, 895 (CA11 2009) (per curiam) (case below); Rendall-Speranza v.

Nassim, 107 F. 3d 913, 918 (CADC 1997) (provision does not authorize

relation back where plaintiff “was fully aware of the potential defen

dant’s identity but not of its responsibility for the harm alleged”);

Cornwell v. Robinson, 23 F. 3d 694, 705 (CA2 1994) (no relation back

where plaintiff knew the identities of the responsible defendants and

failed to name them); Goodman v. Praxair, Inc., 494 F. 3d 458, 469–470

(CA4 2007) (en banc) (rejecting argument that plaintiff’s knowledge of

proper corporate defendant’s existence and name meant that no mis

take had been made); Arthur v. Maersk, Inc., 434 F. 3d 196, 208 (CA3

2006) (“A ‘mistake’ is no less a ‘mistake’ when it flows from lack of

knowledge as opposed to inaccurate description”); Leonard v. Parry, 219

F. 3d 25, 28–29 (CA1 2000) (plaintiff’s knowledge of proper defendant’s

identity was not relevant to whether she made a “ ‘mistake concerning

the identity of the proper party’ ”). We express no view on whether

these decisions may be reconciled with each other in light of their

specific facts and the interpretation of Rule 15(c)(1)(C)(ii) we adopt

today.

8 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

ing; or

“(C) the amendment changes the party or the nam

ing of the party against whom a claim is asserted, if

Rule 15(c)(1)(B) is satisfied and if, within the period

provided by Rule 4(m) for serving the summons and

complaint, the party to be brought in by amendment:

“(i) received such notice of the action that it will not

be prejudiced in defending on the merits; and

“(ii) knew or should have known that the action

would have been brought against it, but for a mistake

concerning the proper party’s identity.” Rule 15(c)(1).

In our view, neither of the Court of Appeals’ reasons for

denying relation back under Rule 15(c)(1)(C)(ii) finds

support in the text of the Rule. We consider each reason

in turn.

A

The Court of Appeals first decided that Krupski either

knew or should have known of the proper party’s identity

and thus determined that she had made a deliberate

choice instead of a mistake in not naming Costa Crociere

as a party in her original pleading. 330 Fed. Appx., at

895. By focusing on Krupski’s knowledge, the Court of

Appeals chose the wrong starting point. The question

under Rule 15(c)(1)(C)(ii) is not whether Krupski knew or

should have known the identity of Costa Crociere as the

proper defendant, but whether Costa Crociere knew or

should have known that it would have been named as a

defendant but for an error. Rule 15(c)(1)(C)(ii) asks what

the prospective defendant knew or should have known

during the Rule 4(m) period, not what the plaintiff knew

or should have known at the time of filing her original

Cite as: 560 U. S. ____ (2010) 9

Opinion of the Court

complaint.3

Information in the plaintiff’s possession is relevant only

if it bears on the defendant’s understanding of whether

the plaintiff made a mistake regarding the proper party’s

identity. For purposes of that inquiry, it would be error to

conflate knowledge of a party’s existence with the absence

of mistake. A mistake is “[a]n error, misconception, or

misunderstanding; an erroneous belief.” Black’s Law

Dictionary 1092 (9th ed. 2009); see also Webster’s Third

New International Dictionary 1446 (2002) (defining “mis

take” as “a misunderstanding of the meaning or implica

tion of something”; “a wrong action or statement proceed

ing from faulty judgment, inadequate knowledge, or

inattention”; “an erroneous belief”; or “a state of mind not

in accordance with the facts”). That a plaintiff knows of a

party’s existence does not preclude her from making a

mistake with respect to that party’s identity. A plaintiff

may know that a prospective defendant—call him party

A—exists, while erroneously believing him to have the

status of party B. Similarly, a plaintiff may know gener

ally what party A does while misunderstanding the roles

that party A and party B played in the “conduct, transac

tion, or occurrence” giving rise to her claim. If the plaintiff

sues party B instead of party A under these circum

stances, she has made a “mistake concerning the proper

party’s identity” notwithstanding her knowledge of the

existence of both parties. The only question under Rule

——————

3 Rule 15(c)(1)(C) speaks generally of an amendment to a “pleading”

that changes “the party against whom a claim is asserted,” and it

therefore is not limited to the circumstance of a plaintiff filing an

amended complaint seeking to bring in a new defendant. Nevertheless,

because the latter is the “typical case” of Rule 15(c)(1)(C)’s applicability,

see 3 Moore’s Federal Practice §15.19[2] (3d ed. 2009), we use this

circumstance as a shorthand throughout this opinion. See also id.,

§15.19[3][a]; Advisory Committee’s 1966 Notes on Fed. Rule Civ.

Proc. 15, 28 U. S. C. App., pp. 122–123 (hereinafter Advisory Commit

tee’s 1966 Notes).

10 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

15(c)(1)(C)(ii), then, is whether party A knew or should

have known that, absent some mistake, the action would

have been brought against him.

Respondent urges that the key issue under Rule

15(c)(1)(C)(ii) is whether the plaintiff made a deliberate

choice to sue one party over another. Brief for Respondent

11–16. We agree that making a deliberate choice to sue

one party instead of another while fully understanding the

factual and legal differences between the two parties is the

antithesis of making a mistake concerning the proper

party’s identity. We disagree, however, with respondent’s

position that any time a plaintiff is aware of the existence

of two parties and chooses to sue the wrong one, the

proper defendant could reasonably believe that the plain

tiff made no mistake. The reasonableness of the mistake

is not itself at issue. As noted, a plaintiff might know that

the prospective defendant exists but nonetheless harbor a

misunderstanding about his status or role in the events

giving rise to the claim at issue, and she may mistakenly

choose to sue a different defendant based on that misim

pression. That kind of deliberate but mistaken choice does

not foreclose a finding that Rule 15(c)(1)(C)(ii) has been

satisfied.

This reading is consistent with the purpose of relation

back: to balance the interests of the defendant protected

by the statute of limitations with the preference expressed

in the Federal Rules of Civil Procedure in general, and

Rule 15 in particular, for resolving disputes on their mer

its. See, e.g., Advisory Committee’s 1966 Notes 122; 3

Moore’s Federal Practice §§15.02[1], 15.19[3][a] (3d ed.

2009). A prospective defendant who legitimately believed

that the limitations period had passed without any at

tempt to sue him has a strong interest in repose. But

repose would be a windfall for a prospective defendant

who understood, or who should have understood, that he

escaped suit during the limitations period only because

Cite as: 560 U. S. ____ (2010) 11

Opinion of the Court

the plaintiff misunderstood a crucial fact about his iden

tity. Because a plaintiff’s knowledge of the existence of a

party does not foreclose the possibility that she has made

a mistake of identity about which that party should have

been aware, such knowledge does not support that party’s

interest in repose.

Our reading is also consistent with the history of Rule

15(c)(1)(C). That provision was added in 1966 to respond

to a recurring problem in suits against the Federal Gov

ernment, particularly in the Social Security context.

Advisory Committee’s 1966 Notes 122. Individuals who

had filed timely lawsuits challenging the administrative

denial of benefits often failed to name the party identified

in the statute as the proper defendant—the current Secre

tary of what was then the Department of Health, Educa

tion, and Welfare—and named instead the United States;

the Department of Health, Education, and Welfare itself;

the nonexistent “Federal Security Administration”; or a

Secretary who had recently retired from office. Ibid. By

the time the plaintiffs discovered their mistakes, the

statute of limitations in many cases had expired, and the

district courts denied the plaintiffs leave to amend on the

ground that the amended complaints would not relate

back. Rule 15(c) was therefore “amplified to provide a

general solution” to this problem. Ibid. It is conceivable

that the Social Security litigants knew or reasonably

should have known the identity of the proper defendant

either because of documents in their administrative cases

or by dint of the statute setting forth the filing require

ments. See 42 U. S. C. §405(g) (1958 ed., Supp. III).

Nonetheless, the Advisory Committee clearly meant their

filings to qualify as mistakes under the Rule.

Respondent suggests that our decision in Nelson v.

Adams USA, Inc., 529 U. S. 460 (2000), forecloses the

reading of Rule 15(c)(1)(C)(ii) we adopt today. We dis

agree. In that case, Adams USA, Inc. (Adams), had ob

12 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

tained an award of attorney’s fees against the corporation

of which Donald Nelson was the president and sole share

holder. After Adams became concerned that the corpora

tion did not have sufficient funds to pay the award, Adams

sought to amend its pleading to add Nelson as a party and

simultaneously moved to amend the judgment to hold

Nelson responsible. The District Court granted both

motions, and the Court of Appeals affirmed. We reversed,

holding that the requirements of due process, as codified

in Rules 12 and 15 of the Federal Rules of Civil Procedure,

demand that an added party have the opportunity to

respond before judgment is entered against him. Id., at

465–467. In a footnote explaining that relation back does

not deny the added party an opportunity to respond to the

amended pleading, we noted that the case did not arise

under the “mistake clause” of Rule 15(c):4 “Respondent

Adams made no such mistake. It knew of Nelson’s role

and existence and, until it moved to amend its pleading,

chose to assert its claim for costs and fees only against

[Nelson’s company].” Id., at 467, n. 1.

Contrary to respondent’s claim, Nelson does not suggest

that Rule 15(c)(1)(C)(ii) cannot be satisfied if a plaintiff

knew of the prospective defendant’s existence at the time

she filed her original complaint. In that case, there was

nothing in the initial pleading suggesting that Nelson was

an intended party, while there was evidence in the record

(of which Nelson was aware) that Adams sought to add

him only after learning that the company would not be

able to satisfy the judgment. Id., at 463–464. This evi

——————

4 The “mistake clause” at the time we decided Nelson was set forth in

Rule 15(c)(3). 529 U. S., at 467, n. 1; 528 F. R. D. 525, 529 (1991). Rule

15(c) was renumbered in 2007 without substantive change “as part of

the general restyling of the Civil Rules,” at which time it received its

current placement in Rule 15(c)(1)(C)(ii). Advisory Committee’s 2007

Notes on Fed. Rule Civ. Proc. 15, 28 U. S. C. App., p. 37 (2006 ed.,

Supp. II).

Cite as: 560 U. S. ____ (2010) 13

Opinion of the Court

dence countered any implication that Adams had origi

nally failed to name Nelson because of any “mistake con

cerning the proper party’s identity,” and instead suggested

that Adams decided to name Nelson only after the fact in

an attempt to ensure that the fee award would be paid.

The footnote merely observes that Adams had originally

been under no misimpression about the function Nelson

played in the underlying dispute. We said, after all, that

Adams knew of Nelson’s “role” as well as his existence.

Id., at 467, n. 1. Read in context, the footnote in Nelson is

entirely consistent with our understanding of the Rule:

When the original complaint and the plaintiff’s conduct

compel the conclusion that the failure to name the pro

spective defendant in the original complaint was the result

of a fully informed decision as opposed to a mistake con

cerning the proper defendant’s identity, the requirements

of Rule 15(c)(1)(C)(ii) are not met. This conclusion is in

keeping with our rejection today of the Court of Appeals’

reliance on the plaintiff’s knowledge to deny relation back.

B

The Court of Appeals offered a second reason why Krup

ski’s amended complaint did not relate back: Krupski had

unduly delayed in seeking to file, and in eventually filing,

an amended complaint. 330 Fed. Appx., at 895. The

Court of Appeals offered no support for its view that a

plaintiff’s dilatory conduct can justify the denial of relation

back under Rule 15(c)(1)(C), and we find none. The Rule

plainly sets forth an exclusive list of requirements for

relation back, and the amending party’s diligence is not

among them. Moreover, the Rule mandates relation back

once the Rule’s requirements are satisfied; it does not

leave the decision whether to grant relation back to the

district court’s equitable discretion. See Rule 15(c)(1) (“An

amendment . . . relates back . . . when” the three listed

requirements are met (emphasis added)).

14 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

The mandatory nature of the inquiry for relation back

under Rule 15(c) is particularly striking in contrast to the

inquiry under Rule 15(a), which sets forth the circum

stances in which a party may amend its pleading before

trial. By its terms, Rule 15(a) gives discretion to the

district court in deciding whether to grant a motion to

amend a pleading to add a party or a claim. Following an

initial period after filing a pleading during which a party

may amend once “as a matter of course,” “a party may

amend its pleading only with the opposing party’s written

consent or the court’s leave,” which the court “should

freely give . . . when justice so requires.” Rules 15(a)(1)–

(2). We have previously explained that a court may con

sider a movant’s “undue delay” or “dilatory motive” in

deciding whether to grant leave to amend under Rule

15(a). Foman v. Davis, 371 U. S. 178, 182 (1962). As the

contrast between Rule 15(a) and Rule 15(c) makes clear,

however, the speed with which a plaintiff moves to amend

her complaint or files an amended complaint after obtain

ing leave to do so has no bearing on whether the amended

complaint relates back. Cf. 6A C. Wright, A. Miller, & M.

Kane, Federal Practice and Procedure §1498, pp. 142–143,

and nn. 49–50 (2d ed. 1990 and Supp. 2010).

Rule 15(c)(1)(C) does permit a court to examine a plain

tiff’s conduct during the Rule 4(m) period, but not in the

way or for the purpose respondent or the Court of Appeals

suggests. As we have explained, the question under Rule

15(c)(1)(C)(ii) is what the prospective defendant reasona

bly should have understood about the plaintiff’s intent in

filing the original complaint against the first defendant.

To the extent the plaintiff’s postfiling conduct informs the

prospective defendant’s understanding of whether the

plaintiff initially made a “mistake concerning the proper

party’s identity,” a court may consider the conduct. Cf.

Leonard v. Parry, 219 F. 3d 25, 29 (CA1 2000) (“[P]ost

filing events occasionally can shed light on the plaintiff’s

Cite as: 560 U. S. ____ (2010) 15

Opinion of the Court

state of mind at an earlier time” and “can inform a defen

dant’s reasonable beliefs concerning whether her omission

from the original complaint represented a mistake (as

opposed to a conscious choice)”). The plaintiff’s postfiling

conduct is otherwise immaterial to the question whether

an amended complaint relates back.5

C

Applying these principles to the facts of this case, we

think it clear that the courts below erred in denying rela

tion back under Rule 15(c)(1)(C)(ii). The District Court

held that Costa Crociere had “constructive notice” of

Krupski’s complaint within the Rule 4(m) period. App. to

Pet. for Cert. 15a–17a. Costa Crociere has not challenged

this finding. Because the complaint made clear that Krup

ski meant to sue the company that “owned, operated,

managed, supervised and controlled” the ship on which

she was injured, App. 23, and also indicated (mistakenly)

that Costa Cruise performed those roles, id., at 23–27,

Costa Crociere should have known, within the Rule 4(m)

period, that it was not named as a defendant in that com

plaint only because of Krupski’s misunderstanding about

which “Costa” entity was in charge of the ship—clearly a

“mistake concerning the proper party’s identity.”

Respondent contends that because the original com

plaint referred to the ticket’s forum requirement and

presuit claims notification procedure, Krupski was clearly

aware of the contents of the ticket, and because the ticket

identified Costa Crociere as the carrier and proper party

——————

5 Similarly,we reject respondent’s suggestion that Rule 15(c) requires

a plaintiff to move to amend her complaint or to file and serve an

amended complaint within the Rule 4(m) period. Rule 15(c)(1)(C)(i)

simply requires that the prospective defendant has received sufficient

“notice of the action” within the Rule 4(m) period that he will not be

prejudiced in defending the case on the merits. The Advisory Commit

tee Notes to the 1966 Amendment clarify that “the notice need not be

formal.” Advisory Committee’s 1966 Notes 122.

16 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

for a lawsuit, respondent was entitled to think that she

made a deliberate choice to sue Costa Cruise instead of

Costa Crociere. Brief for Respondent 13. As we have

explained, however, that Krupski may have known the

contents of the ticket does not foreclose the possibility that

she nonetheless misunderstood crucial facts regarding the

two companies’ identities. Especially because the face of

the complaint plainly indicated such a misunderstanding,

respondent’s contention is not persuasive. Moreover,

respondent has articulated no strategy that it could rea

sonably have thought Krupski was pursuing in suing a

defendant that was legally unable to provide relief.

Respondent also argues that Krupski’s failure to move

to amend her complaint during the Rule 4(m) period

shows that she made no mistake in that period. Id., at

13–14. But as discussed, any delay on Krupski’s part is

relevant only to the extent it may have informed Costa

Crociere’s understanding during the Rule 4(m) period of

whether she made a mistake originally. Krupski’s failure

to add Costa Crociere during the Rule 4(m) period is not

sufficient to make reasonable any belief that she had

made a deliberate and informed decision not to sue Costa

Crociere in the first instance.6 Nothing in Krupski’s con

duct during the Rule 4(m) period suggests that she failed

to name Costa Crociere because of anything other than a

mistake.

It is also worth noting that Costa Cruise and Costa

——————

6 The Court of Appeals concluded that Krupski was not diligent

merely because she did not seek leave to add Costa Crociere until 133

days after she filed her original complaint and did not actually file an

amended complaint for another a month after that. 330 Fed. Appx., at

895. It is not clear why Krupski should have been found dilatory for

not accepting at face value the unproven allegations in Costa Cruise’s

answer and corporate disclosure form. In fact, Krupski moved to

amend her complaint to add Costa Crociere within the time period

prescribed by the District Court’s scheduling order. See App. 3, 6–7;

Record, Doc. 23, p. 1.

Cite as: 560 U. S. ____ (2010) 17

Opinion of the Court

Crociere are related corporate entities with very similar

names; “crociera” even means “cruise” in Italian. Cassell’s

Italian Dictionary 137, 670 (1967). This interrelationship

and similarity heighten the expectation that Costa Croci

ere should suspect a mistake has been made when Costa

Cruise is named in a complaint that actually describes

Costa Crociere’s activities. Cf. Morel v. DaimlerChrysler

AG, 565 F. 3d 20, 27 (CA1 2009) (where complaint con

veyed plaintiffs’ attempt to sue automobile manufacturer

and erroneously named the manufacturer as Daimler-

Chrysler Corporation instead of the actual manufacturer,

a legally distinct but related entity named DaimlerChrys

ler AG, the latter should have realized it had not been

named because of plaintiffs’ mistake); Goodman v. Prax

air, Inc., 494 F. 3d 458, 473–475 (CA4 2007) (en banc)

(where complaint named parent company Praxair, Inc.,

but described status of subsidiary company Praxair Ser

vices, Inc., subsidiary company knew or should have

known it had not been named because of plaintiff’s mis

take). In addition, Costa Crociere’s own actions contrib

uted to passenger confusion over “the proper party” for a

lawsuit. The front of the ticket advertises that “Costa

Cruises” has achieved a certification of quality, App. to

Pet. for Cert. 25a, without clarifying whether “Costa

Cruises” is Costa Cruise Lines, Costa Crociere, or some

other related “Costa” company. Indeed, Costa Crociere is

evidently aware that the difference between Costa Cruise

and Costa Crociere can be confusing for cruise ship pas

sengers. See, e.g., Suppa v. Costa Crociere, S. p. A., No.

07–60526–CIV, 2007 WL 4287508, *1, (SD Fla., Dec. 4,

2007) (denying Costa Crociere’s motion to dismiss the

amended complaint where the original complaint had

named Costa Cruise as a defendant after “find[ing] it

simply inconceivable that Defendant Costa Crociere was

not on notice . . . that . . . but for the mistake in the origi

nal Complaint, Costa Crociere was the appropriate party

18 KRUPSKI v. COSTA CROCIERE S. P. A.

Opinion of the Court

to be named in the action”).

In light of these facts, Costa Crociere should have

known that Krupski’s failure to name it as a defendant in

her original complaint was due to a mistake concerning

the proper party’s identity. We therefore reverse the

judgment of the Court of Appeals for the Eleventh Circuit

and remand the case for further proceedings consistent

with this opinion.

It is so ordered.

Cite as: 560 U. S. ____ (2010) 1

Opinion of SCALIA, J.

SUPREME COURT OF THE UNITED STATES

_________________

No. 09–337

_________________

WANDA KRUPSKI, PETITIONER v. COSTA

CROCIERE S. P. A.

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF

APPEALS FOR THE ELEVENTH CIRCUIT

[June 7, 2010]

JUSTICE SCALIA, concurring in part and concurring in

the judgment.

I join the Court’s opinion except for its reliance, ante, at

10–11, 15, n. 5, on the Notes of the Advisory Committee as

establishing the meaning of Federal Rule of Civil Proce

dure 15(c)(1)(C). The Advisory Committee’s insights into

the proper interpretation of a Rule’s text are useful to the

same extent as any scholarly commentary. But the Com

mittee’s intentions have no effect on the Rule’s meaning.

Even assuming that we and the Congress that allowed the

Rule to take effect read and agreed with those intentions,

it is the text of the Rule that controls. Tome v. United

States, 513 U. S. 150, 167–168 (1995) (SCALIA, J., concur

ring in part and concurring in judgment).