1 (Slip Opin i o n) OCTOBER T ERM, 20 09 Sy llabu s N O TE : Wh er e it i s feas ibl e , a s y llab u s (h ead n ot e) wil lbe rel e as ed , as is bein g d o n e incon n ecti onwithth is cas e , a tth e ti meth e op in i o n is is s u ed

. Th e s y ll abu s con s titu tes n o p a rt of th e op in i o nof th eC o u r t bu t h a s be en pre p are dbyt h e Re po rte ro f De ci sio n s fo r t h e co nveni e nce of t h e reade r . Se e United Statesv. Detroit Timbe r& Lumb er Co., 200U. S

. 3 21, 337

. 

# SUPREME CO URT O FTHE UNI TED STATES
Sy llabu s 

### KRU P S KI v . COSTA CROCIER E S. P 

### . A. CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE ELEVE NTH CIRCUI T No. 09–3 37. Ar g u ed Apr il 21, 201 0—Dec i ded Ju n e7, 2010 PetitionerKrupski sought c o mpensati on for injuries she suffered on a

c r u ise sh ip. Herpassen g ertic k et, w h ic h w a s is su ed byCost a Cr u i se Lines, identifi ed respondent Costa Cr ociere S

. p. A. a s t h e ca rrier; re qu ir ed anin ju r e d par t yto s u bmit to the c a r r i erorits ag ent wr itten not i ce of aclaim ; req u ired a n y la ws uit to be filed withi none year of the injury; and designateda specificFeder a l District Co urt as the ex

clus ive forumfor la ws uit s such a s Kr upski’s. The front of the ticket listed Co st a Cruise’s Florida addre ss and made r e fer e nces to “Cost a Cr u i ses. ” Af terKr u p ski’ s at tor n eyn o tified Co st a C r u i se of h e r c l aims but di dnot r e ac h a se ttlement, Kr upski fileda d i v e r s itynegli

gencea c tion a g a i ns t Cos t aCruis e . O v er the next s e ve r a l months— after the limit ations period had ex pired—Cost a Cruise brough t Costa Crociere’s exis tence to Krup ski’s at tentionthr ee times, inc l udingin its mo tion for summar yjudg ment, inw h i c hit stated th a tCost a Cr o ciere was the proper defendant. Krupski responded and moved to amen d h e rc o mplain t to ad d Costa Cr oc ie r eas a defen d an t. Th e Dis

tr ic t Cour t denied Costa Cr uise’ s summ ar yjudg ment motion without prejudice and granted Krupski leav e to amend. Afte r she served Cost a Cr oc ier ewithanamen ded c o mplaint, the c o ur t dismi ssed Cost a Cr u i se f r om th e c a se. Th er eafter, Costa Crociere—represented byth e s a me c o u n s el as Cos t a Cr u i se—mo v ed to di smi s s, contending that the amen ded complaintdid not sati sf ythe r e quir ements of Fed

eral Rule of Civil Procedure15(c) , which gover n s whenan amended pleading “relates back” to the date of ati mely filedoriginal ple a ding and is thus timelyev en thoughit was filed outside an applicable li mi

tations period

. The Rule r e quires, inter alia, that wi t h in the Rule 4 ( m) 12 0

- da y period for s e rvice a f t e r acom p la int is filed, t h e newly named defend ant “knew orshould hav eknown that the ac tion would2 KRUPSKI v. COSTA CROC I ERE S. P . A. Sy llabu s h av ebeenbr ou gh t ag ain s t it, bu t fo r a mistake concerni ng the p r oper party’s identity.” Rule 15(c)(1)(C)(ii). The Dis t rict Court found this c o ndition fatalto Kr upski’ s atte mpt to r e l a te b a c k

. It c o nc luded that she had not made a mis t a k e about the proper party’sidentity be

c a u s e, alth ou ghCosta Cr u i se h a d disc losed Costa Cr oc ier e ’ s r o le in several court filings, she nonetheless del a yed for months filing an amended complaint. The EleventhCircuit affirmed, finding that Krupski either knew or sho u ld haveknown of Costa Crociere’s iden

tityas a pote ntial par t ybe c a use sh e furnished the ticket identifying it to her counsel well before the limi t a t i o ns period ended. It wa s therefore appropriate to treat her as havin gchosen to sue one poten

tial p a rty over another. A ddition al ly , the c o ur t held that r e lation back was not appropriate because of Krupski’s undue delay in seek

ingto amend the c o mplaint. Held: Relationbac k u n d erRu le 15(c )(1)(C) depen d s onwh at th e par t y

to be added k n ew or should have known, not on the ame n ding party’s kn owledg e ort i melin es s inseekin gto amend th e pleadin g . Pp. 7–18.

(a) The Rule’s text does not suppo rtt h e Elevent hCircuit ’ s decis i on to rely on the plaintiff’s knowledg e in denying relation back. The question under Rule 15(c)(1)(C)(ii) is not whether Krupski knew or should have k n own Costa Crociere’s identi ty as the proper defendant, but whether Costa Crociere knew orsh ou l dh av ek n ow nd u r i ngth e Ru le 4(m) per i od th at it wou l d h av ebeenn a med as th e d e fen d an t bu t for an error. The plaintiff’s informat ion is relevant only if it bears on the defenda n t’s unders t a n ding of whether the pl aintiff made a mis

t a ke rega rdin g t h e prope rp a rt y’s ident i t y . Itwo uld b e errort ocon flate knowled g e of a party’ s existenc e wi th the absence of mi stake. Tha ta pl ai nt iff knows of a pa rt y’ s existe nce does not preclude her fr om making a mi st ake wit hr e spec t to that p a r t y ’ s iden tity

. M a king a deliberate c h oice to sue o n e party o v er another whileunderstand

ing the factua l and legal d i f f erence s between the two p a r t ies may be the antithesis of makinga mistake, bu t th at does n o t m e anth at an y time a pl ain t if f is aw ar e of t h e ex is tence of two partie s and chooses to sue the wrong one, the p r oper de fen d ant c o u l d r e ason ablybeliev e that the plain t iff m a de no mist ake. A pl aintiff m i gh t know that the prospective de fendant exist s but no nethele ss choose to sue a d i fferent defen d an t ba s e d ona misu n d er stan din gabou tth e pr o p erpar t y ’ s identity. That kind of deliberate bu t mis t a k en choic eshould not for e close a finding that Rule 15( c)(1)(C)(ii) h a s b e e ns a t i s f i e d

. T h i s r e a d

ing is consiste nt with relatio nbac k’s purpose of bal a ncing the defen

dant’ s inter e s t s pr otec ted bythe st atut e of lim ita t io ns with the preference of the Federal Rules of Civil Procedure i n general, and Rule 15 in par t icular, for res o lving disp utes on their merits. It i s al so cons is tent with the his t ory of Rule15(c)(1)(C). And it is not fore

-3 Cite as: 56 0 U

. S. ____ (2010) Sy llabu s closed by Nelsonv. A d am s U S

A, In c. , 529 U. S. 460. Pp. 7–13. (b) The Eleventh Circuit also e rred in ruling that Krupski’s undue delay in seek i n g to file, an d in eventuall yfiling, an a m ended com

plaint jus t ifie d its denia lof relati on back under Rule 15(c)(1)(C). The Rule pla i nly sets forth a nexclus iv e list of requirement s for relation bac k, an d th e plain t iff’ s dili g e n c e is not among them. Moreove r , it man d ate s r e la tionbac k on c eits r e qu ire m ents are sat i sfied; itdoe s not leav e that dec i sion to the distr i c tc o ur t’ s equit able dis c r e tion. Its ma nda t ory nature is pa rtic ula r ly s t riking in cont ra s tt ot h e inq u iry under Ru le 1 5 ( a) , whichgives adis t rict cou r tdis cret i on t odecide whetherto gr ant a motion to amen d a p l eading before trial. Se e Fomanv. Davis , 371 U. S. 1 78, 1 82. Ru le 15(c )(1)(C) per m its ac o u r t to examine a plaintiff’s con d uct duri ng the Rule 4(m) pe riod, but only to the extent t h e plaintiff’s p o stf iling conduct informs the prospectiv e defenda n t’s unders t a n ding of whethe r the plaintiff init ially ma de a “mistake concerning the pro p er party’ s ide n tity

. ” Th e pl ain t iff’ s po st

filing conduct is otherwise i mma terialto the relation-b ack question

. Pp. 13–1 5.

(c) Under thes e principles, t h e courts below erred in de nying rela

tion back. Because the original complaint(of which Co sta Crocier e had c o nstr uc tiv enotic e ) made c l earthat Kr upski meant to sue the company that “owned, operated, mana ged, supervised an d controlled” the ship on which she was injured and also indicated ( m ist a kenly) th at Cost a Cr u i se per f or med th ose r o les, Cost a Cr oc ier esh ou ld h av e known that it avoided suit w i thin the limit ations period only because of Krupski’ s misunder stan dingabout whic h “Costa” entitywas in charge of the ship—cle ar lya “mi stake c o n c ern i ng the proper party’s identity .” Th at Kr upski m a yhav e known the ticket’s contents does not foreclose the possibili ty that she nonetheless misun d erstood cru

cia lfa ct s regarding t h e t w o com p a n ies ’ ident i t i es . Es pecia lly b e ca use the fac eof the c o mplaint pla i nly in dic a ted su c ha misu nder stan din g , respondent’s contention that it wa s enti t l ed to think she made no mis t a k e is not pers ua s ive. Moreove r , res p ondent ha s a r ticula ted no s t ra tegy tha tit could rea s on ab l y have thought Kr ups k i wa s purs uing in suing a defendant that was legallyunable to provide relief. Noth

ing in Kr ups k i’s conduct du ring the Rule 4 ( m) period sugges t s that she failed to name Cost a Crociere bec a u s e of an y t h i ng oth e rth ana mist ake. The inter r e lations h ip be tweenC o sta Cr u i se an d Cos t a Cr o ciere and thei r similar names heighten th e expe ctatio n that Costa Cr oc ier esh ou l dsu spec t a m i stake w h enCostaCr u i se i s n a med in a c o mplain t ac t u allydesc r ibi n gCosta Cr oc i e r e ’ s ac tiv i ties

. Inaddition , Costa Crociere’s own actions contrib u ted to pa ss enger c o nfus ion ove r “the proper party”: The fro n t of th e ticket advertises that “Co s ta Cr u i ses” h a s ac h i ev ed a c e r t ific ationof qu alitywith o u t c l ar ify i ng4 KRUPSKI v. COSTA CROC I ERE S. P . A. Sy llabu s whic h “Costa” c o mpanyis meant. And as shown in similar lawsuits, Cost a Crociere is evidently well aw are that the difference between it an d Costa Cr u i se c a nbe c o n f u s in gfor pass en g e r s . Pp. 15–18. 330 Fed. Appx . 892, r e v e r s ed an d r e man d ed.

S OTOMAYOR , J., delivered the opinion of the Court, in whi c h R OBERTS , C. J., and S TEVENS , K ENNEDY , T HOMAS , G INS B URG , B REY ER , an d ALITO , JJ., joined. S CALIA , J., filedan opinion co ncurring in part and concur

r i ngin the jud g ment._________________

_________________ 1 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt
NOTIC E : Th is op i n ionis subjec t to f o rma lrevi si onbef o r e publicat ioninth e p r eli m in ary p rin t of th e U n it edS t at es R e p o rts

. R e ad ers ar e r e qu es ted to n o tif yth e R e p o rt e rof D e c i s i on s , Su p r em e C o u rt of th e U n ited St at es , Wa s h

ington, D. C. 2054 3, of any typ o gra p hical or other f o rmal err o rs , in or der th atc o rr ect i on sm a y b e mad eb e f o r e th ep r e lim in aryp rin t go es t o p r es s . 

# SUPREME CO URT O FTHE UNI TED STATES

No. 09–3 37 

### WANDA KRUP SKI, P E TITION E R v. COSTA CROCIER E S. P 

### . A. ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEAL S FOR THE ELEV ENTH CIRC U I T [Ju n e7, 2010] 

### J USTICE 

### S OTOMAYOR

### d e livered theopinion of t h e Court. Rule 15(c) of the Federal Rules o f Civil Procedure gov

erns when an amended pleading “relates back” to the da te of a timely filed origin al pleading and is thus itself timel y even though it was filed outside an applicable statute of limitations. Where an amended pleading cha n ges a party or a party’s name, the Rule requires, among other things, that “the party to be brought in by amendm ent .

. . kne w or should have known that the action would have been brought a g a i nst it, but for a mistake concerning the prope r 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 k n ew or should have k n own of the prope r defendant before filin gher or iginal complaint. The cour t also held t hat relation back was not appropriate because the plaintiff had unduly delayed in seeking to amend. We hold that relation bac k under Ru le 15(c)(1)(C) depends on what the party to be added kne wor should have kno w n, not on the amending party’s k n owledge or its timeline ss i n seeking to amend the pleading. Accordin gly , we revers e the judgme nt of the Court of Appe als.2 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### I On Februa ry 21, 2007, petitioner, Wanda Krups k i, tripped ove ra cable and fracture d her femu r while she was on board the cruise ship Costa Magica. Upon her return home, she acqu ired counsel and began the process of seek ing compensation for her i n juries. Krupsk i’s pas

senger ticket—which explained that it was the sole con

tract bet w een 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 an d other shi p s owned, chartered, operated, mark eted or provided by Costa Crociere, S. p. A., and all officers, staff members, crew members, i n depend

ent contract ors, medical providers, concessiona i res, 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 p a rty to submit “wri tte n notice of the claim with full particulars .

. . to the carrier or its duly authorized agent withi n185 days after the da te of injury.” Id., at 28a

. The ticket further required an y lawsuit to be “filed within one year after th e date of in

jury” and to be “served upon the carrier within 120 days after filing.” Ibid. Forcases arising from voy a ges depart

ing from or returning t o a United States port in which the amount in controversy exceeded $ 75,000, the ticket desig

nated the United Sta t es DistrictCourt for the Southern District of Florida in Broward County, Florida, as the exclusive forum for a lawsuit. Id., at 36a. The ticket extended th e “defenses, limitations and excepti o ns . . . that may be invoked by the CAR RIER” to “all persons who may act on behalf of the CARRIER or on whose behalf th e CAR RIER may act,” i n cluding “t he CARRI ER’s paren t s,3 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### subsidiaries , affiliates, successors, assigns, representa

tives, agents, employees, servants, concessionaires and contractors ” as well as “Costa Crui se Lines N. V.,” identi

fied as the “sales and marketing agent for the CARRIE R and the issuer of this Passage Ticket Cont r a ct.” Id., at 29a. The front of th e ticket listed Costa Cruise Lines ’ address in Florida and stated that an entity called “Costa Cruises” was “the firs t cruise company in t h e world” t o obtain a certain certific a tion of quality. Id., at 25a. On July 2, 2007, Krupski’s counsel notified Costa Cruis e Lines of Krupski’s claims. App. 69–70. On July 9, 200 7, the claims administrat o r for CostaCruise requested addi

tional infor m ation from Krupski“[i]n order to facilitate our future attempts to achieve a pre-litigation settlement.” App. to Pet. for Cert. 2 3a–24a. The parties were unable t o reach a settlement, however, and on Februa ry 1, 2008— three weeks before the 1-yearlimitations period expired— Krups k i filed a negligence action against Costa Cruise, invoking th e diversity jurisdi ction of the Federal Distric t Court for t h e Southern Districtof Florida. The complain t alleged tha tCosta Cruise “owned, operated, managed, supervised and control l ed” the ship on which Krups k i ha d injured herself; that Costa Crui se had extended to its passengers an invitation to enter onto the ship; and tha t Costa Crui se owed Krupski a d u ty of car e , which it breached by failing to take steps that would have pre

vented her accident. App. 23–26

. The complaint furth er stated that venue was proper under the passenger tick et’s forum selec t ion clause and averred that, by the July 200 7 notice of her claims, Kru p ski had complied with th e ticket ’s pre s uit requirements. Id., at 23. Krupski served Costa Cruise on Februa ry 4, 2008. Over the next several months—after the limitations period had expired—Costa Crui se brought Costa Croci

ere’s existe nce to Krupsk i’s a tten t ion three t i mes. First, on February 25, 2008, Costa Cru i se filed its answer, as -4 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### serting tha tit was no t the p r oper defendan t, as it wa s merely the North American sales and market ing agent for Costa Croci e re, which was the a c tual carrier and vessel operator. Id., at 31. Second, on March 20, 2008, Costa Cruise listed Costa Cr ociere as an interested party in its corporate di sclosure statement. App. to Pet. fo r Cert. 20a. Finally, on May 6, 2008, Costa Cruise moved for summary judgment, again stating that Costa Crociere was th e 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 dete rmine whether CostaCruise should be dis

missed. Accordingto Kru p ski, t h e following sources o f informationled her to believe Costa Cruise was the re

sponsible p a rty: The travel documents prominently identi

fied Costa Cruise and gave its Florida address; Costa Cruise’s Web site list e d Costa Cruise in Florida as th e United States office for the Italian company Costa Croci

ere; and the Web site of the Florida Department of State listed Costa Cruise as t h e only “Costa” compa n y registere d to do busin ess inthat State. Id., at 43–45, 5 6–59. Krup

ski also obs e rved that Costa Cruis e ’s claims administrator had responded to her claims no tification wit h out indicat

ing that Co sta Cruise was not a responsible party. Id., at 45. With h e r response, Krupski simultaneous l y moved to amend her complaint to add Cos t a Crociere as a defen

dant. Id., at 41–42, 52–54. On July 2, 2008, after oral argument, the Dis trict Cour t denied Costa Cruise’s motion for summary judgment without prejudice and grantedKrupski leave to amend , ordering th at Kru p ski effect proper service on Costa Cro

ciere by Se ptember 16, 2008. Id., at 71–72. Complying with the court’s deadline, Krupskifiled an amended com

plaint on July 11, 20 08, and served Costa Crociere o n August 21, 2008. Id., at 73, 88–8 9. On that same date, the District Court issu ed an order dismissing Costa Cruise5 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### from the case pursuant to the parties’ joint stipulation, Krups k i apparently h aving co ncl u ded that Costa Crui se was correct that it bore no re sponsibility for her injuries. Id., at 85–86. Shortly the r eafter, Costa Crociere —represented by the same counsel who had represented Costa Crui se, compare id., at 31, with id., at 100—moved to dismiss, contending that the a m ended complaint di d not relate back und er Rule 15(c) and was therefore untimely. The District Court agreed. App. to Pet. for Cert. 8a–22a. Rule 15(c), the court expla i ned, imposes three requirement s before an amended complaint against a new l y named defendant can relate back to the original co mplaint. First, the claim against the newly named defendant must ha ve arisen “out of the conduct, t r ansaction, or occurrence set out—or attempted to be set out—in th e original pleading.” Fe d. Rules Civ. Proc. 15(c) (1)(B), (C). Second, “within the period provided by Rule 4(m) for se rving the summons and complaint” (which is ordinarily1 2 0 d a y s f r o mw h e nt h e complaint is filed, s ee Rule 4(m)), the newly named defen

dant must have “received such notice of the action that it will not be prejudiced i ndefending on the merits.” Rul e 15(c)(1)(C)(i). Finally, the plaintiff must show that, within the Rule 4( m) period, the newly named defendant “kne w or should have known that the action would have been brought a g a i nst it, but for a mistake concerning the prope r party’s identity.” Rule 15(c)(1)(C)(i i). The first t w o conditions posed no problem, the court explained: The claim against Co sta Crociere clearly i n volved the same occurrence as the original claim agains t Costa Crui se, and Costa Crocie re had const r uctive notic e of the action and had not shown that any unfair prejudice would result from relation bac k. App. to Pet. for Ce rt. 14a–18a. But the court found the third condition fatal to Krups k i’s attempt to relate back, concluding that Krups k i had not m a de a mistake concerning the identity of the6 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### proper party. Id., at 1 8a–21a. Relying on Eleventh Cir

cuit preced ent, the court explain e d that the word “mis

take” should not be construed to encompass a deliberate decision not to sue a party whos e identity t h e plaintiff knew before the statu t e of limitations had run. Becau s e Costa Crui se informed Krups k i that Costa Crociere was the proper defendant in its answ e r, corporate disclosure statement, and motion for summ ary judgme nt, and yet Krups k i del a yed for mo nths in moving to amend and then in filing anamended complain t, the court concluded that Krups k i knew of the proper defendant and made no mistake. The Eleventh Circuit affirmed in an unpublished per curiam opinion. Kru p skiv. Cos t a Crui se Lines, N. V., LLC, 330 Fed. Appx. 8 92 (2009). Rather tha nrelying on the informa t ion contai ned in Cost a Cruise’s filings, allof which were made after the statute of limitations had expired, as evidence that Krups k i did not make a mistake, the Court o f Appeals noted that the relevant information was locatedwithin Kr upski’s pas s enger ticket, which s h e had furnis hed to her counsel well before the end of the limitations period. Because the tick et clearly identified Costa Croci e re as the carrier, the court stat ed, Krups k i either k n ew or should have k n own of Costa Crociere ’s identity as a potential party. 1 

### It was therefor e appropri

ate to treat Krupsk i as having cho s en to sue one potential party over another. Alternativ ely, even assu ming that she first learned of CostaCrociere’s identity a s the cor r ec t party f r om Costa Cru i se’s answer, the Court of Appeals

——————

1 The Cour t of Appeal s st ate dthat i twas “imput[ing]” k n owledg e to Kr u p s k i

. 3 3 0 F e d

. Ap p x . , a t8 9 5

. P e t i t i o n e ru s e s t h et e r m s “i m p u t e d knowledge” and “construct iv e knowledge”interchangeab ly in her brie f, w h ile r e spon den taddr esses on lyac tu al knowledge. Because we reject the Court of Appeal s’ focus on the plaintiff’s knowledge in the first in stan c e , see infra , at 8–13, the di sti n ction among these types of knowledge is not relevant toour resolution of this case.7 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### observed that Krups k i waited 133 days from the time she filed her original complaint to seekleave to a m end and did not file anamended complaint for another month after that. In light of this delay, the Court of Appe als concluded that the District Court did not abuse its discretion in denying relation back. We granted certiorar i to resolv e tension among the Circuits ove rthe b r eadth of Rule 1 5 (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 tha tp r ov ides the applicable statute of limitations allows relation back; “(B) the am endment asserts a claim or defense that arose out of the condu c t, transa cti on, or occur r ence set out—or atte mpted to be set out—in the original plead

-

——————

2 See, e.g. , Krupskiv. Costa Cruise Lin e s, N. V., LLC, 330 Fed. Ap px . 892, 895 (CA 11 2 0 0 9 ) (per curiam )(c ase below); Rendall-Speranzav. Nassim , 107 F

. 3d 91 3, 91 8 ( CADC 1 9 9 7 ) ( p r o v i siondoes n o t au th or ize r e lationbac k wh er e plain t iff “was fully a w are of the p o tential defen

dant’ s identit ybut not of its r e sponsibil i tyforthe har malleg e d”); Cornwell v. Robinson , 23 F. 3d 694, 7 05 ( CA2 1 9 9 4) (n o r e lationbac k where plaintiff knew the id entities of th e r e spon sible d e fen d an ts an d failed to name them); Goo d manv. P raxai r, Inc. , 494 F. 3d 458, 46 9– 4 7 0 (CA4 20 07) (e nban c ) (r ejec tin gar g u men tth at p l ain t iff’ s kn owledg e of pr operc o r p orate defendant’ s ex istenc e and name mean t that no mi s take had beenmade); Arthu rv. Mae rsk, I n c. , 434 F. 3d 196, 2 08 (C A3 2 0 0 6) (“A ‘m is t a ke ’ is no le s s a‘m is ta ke ’ whe ni tfl ows fro mla ck o f knowledge as opposed to inaccurate description”); Leonardv. Parry , 219 F. 3d 25, 28–2 9 (CA 1 20 00) (plain tiff’ s kn owledg e of pr operdefen d an t’ s identitywas not r e lev a nt to whethershe made a “ ‘mista ke concer nin g the identity o f the proper party’ ”). We express no view on whethe r these decision s may be reconciled with each other in light of thei r spec ificfac t s and the inter p r e tationof Rule 15(c)(1)( C)(ii) we ado p t today

.8 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### ing; or “(C) the am endment changes the party or the nam ing of the partyagain s t 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 defen d ing on the merits; and “(ii) k n ew or should have k n own 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 re lation back under Ru le 15(c)(1)(C)(ii) finds support in the text of the Rule. We consider each reas on in turn. A The Court of Appeals first decided that Kru p ski either k n ew or should have k n own of the proper party’s identit y and thus determined that she had made a deliberat e choice instead of a mis t ake in not naming Costa Crociere as a party in her original pleadin g . 330 Fed. Appx., a t 895. By focusing on Krups k i’s knowledge, the Court o f Appeals chose the wrong starting point. The questio n under Rule 15(c)(1)(C)(ii) is not whether Kru p ski knew o r should have k n own the identity of Costa Cro c iere as the proper defe ndant, but whether Costa Cro c iere knew or should have known that it would have beennamed as a defendant but for an error. Ru le 15(c)(1)(C)(ii) asks what the prospective defen dant k n ew or should have k n own during the Rule 4(m) period, not what the pl aintiff kne w or should have known at the ti me of filin g her origi nal9 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### complaint. 3 

### Informationin the pla i ntiff’s possession i s relevant onl y if it bears on the defendant’s un derstanding of whether the plaintiff made a mistak e regarding the proper party’s identity. F o r purposes of that inq u iry, it would be error to conflate k n owledge of a party’s existence with the absence of mistake. A mistake is “[a]n error, misconception, or misunderstanding; anerroneous belief.” Black’s La w Dictionary 1092 (9th ed. 2009); see also Web ster’s Third New International Dictionary 1446 (2002) (d efining “mis

take” as “amisunderstanding of the meaning or implica

tion of som e thing”; “a wrong action or statement proceed

ing from faulty judgment, inadequate knowledge, or inattention”; “an erroneous belief ”; or “a state of mind not in accordan ce with the facts”). Th at a plaintiff knows of a party’s existence does not preclude her fro mmak i ng a mistake wi th respect t o that par t y’s identit y . A plaintif f may know that a prospective defendant—cal l him party A—exists, while erroneously bel i eving him to have the status of party B. Si milarly, a p l aintiff may know gener

ally what party A does while misunderstanding the roles that part y A and part y B played in the “conduct, trans ac tion, or occurrence” gi ving rise to her claim. If the plaintiff sues party B instead of party A under these circum

stances, she has made a “mista ke concerning the prope r party ’s identity” not w ithstandingher knowledge of the existence of both parties. The only question under Rule

——————

3 Ru le 15(c )(1)( C) speak s g e n e r a llyof ana m en dmen t to a “ple adin g” th at c h an g e s “th e par t yag ain s t wh om ac l aim i s as s e r t ed,” an d it therefore is not li mitedto the ci rcumsta nce of a pla i ntiff filing an amended com p laint seek ing to bring inanew defenda n t. Nevertheles s , because the l a tter is the “ t ypical case ” of R u le 15(c)(1)(C)’ s app licab ility, see 3 Moore’s Federal Practice §15. 19 [2 ] (3 d ed. 20 09), we us e t h i s c i r c u mstanc e as a shor than d thr o ughout this opinion. See also id., §15.19[ 3][a]; Adv i sor yCo mmit t ee’ s 19 66 Notes onFed. Ru le Civ

. Pr oc . 15, 28 U. S. C. App., pp. 122– 12 3 (h er ein a fterAdv i sor yCommi t

tee’ s 196 6 Not e s).10 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### 15(c)(1)(C)(i i), then, is whether party A kne wor should have known that, abs ent some mistake, the action woul d have been b r ought agai nst him. Respondent urges that the key issue u n der Rul e 15(c)(1)(C)(i i) is whether the plaintiff made a deliberate choice to su e one party over another. Brief for Respondent 11–16. We agree tha tmaking a deliberate choice to sue one party instead of a n other while fully unde r standing the factual and legal differences between the t w o p a rties is the antithesis of making a mist ak e concerning the proper party ’s identity. We disagree, however, with respondent’s position tha tany time a plaintiff is aware of the existence of two parties and chooses to sue the wrong one, t h e proper defe ndant 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 kno wth at the prospective defendant exis ts 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 s u e a different defendant based on that misim

pression. That k i nd of deliber ate b u t mistak e nchoice does not foreclose a finding that Rule 15(c)(1)(C)(i i) has been satisfied. This reading is consistent with th e purpose of relation back: to balance the interests of the defendant protected by the statute of limitations with the preference expressed in the Fed e ral 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 a t

tempt to sue him has a strong interest in repose. B u t repose would be a wi ndfall for a prospecti ve defendant who understood, or who shouldhave understo o d, that he escaped suit during th e lim itations period only because11 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### the plaintiff misunderstood a cru cial fact ab out his iden

tity. Because a plaintiff’s k n o w ledge of the existence of a party does not foreclos e the possibility that she has mad e a mistake o f identity a b out which that pa rty should have been aware, such k n owledge d oes not support that party’s interest in repose. Our readin g is also consistent with the history of Rule 15(c)(1)(C). That provi s ion was added in 1966 to respond to a recurring problem in su its against the F e deral Gov

ernment, particularlyin the S o cial Security context

. Advisory Committee’s 1966 Notes 122. Individuals wh o had filed timely lawsuits challenging the administrative denial of benefits often failed to name the party identifie d in the statu t e as the proper defendant—the cu rrent Secre

tary of wha twas then the Depart ment of Health, Educa

tion, and W e lfare—and named instead the United States; the Department of Health, Educa t ion, and Welfare its e lf; the nonexis t ent “Federal Secu rityAdministration”; or a Secretar y who had re cently retir e d from office. Ibid. B y the time t h e plaintiff s discovered their mi stak es, the statute of limitations in many cas e s had expired, and th e district cou rts denied the plai ntiff s leave to a m end on th e ground tha tthe amended co mplaints 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 k n own the identityof the proper defendant either because of documents in their administrative case s or by dint of the stat ute setting forth the f iling requir e ments. See 42 U. S. C. §405(g) (1958 ed., Supp. III). Nonetheless, the Advisory Committee clearly meant their filings to qu alify as mis t akes under the Rule. Respondent suggests that our decision in Nelsonv. Adams USA, Inc. , 52 9 U. S. 460 (2000), f o recloses 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 CROC I ERE S. P . A. Opinion of theCourt 

### tained an a w ard of attorney’s fees against the corporation of which Do nald Nelson was the president and sole share

holder. After Adams b e came concerned that the corpora

tion did not have sufficient funds to pay the award, Ada m s sought to a m end its pleading to a dd Nelson a s a party and simultaneously moved to amendthe judgment to h o ld Nelson responsible. The Distri ct Cour t gr anted bot h motions, an d the Court of Appeals affirmed. We reversed, holding that the requirements of due process , as codifi e d in Rules 12 and 15 of th e Federal Rules of Civil Procedure, demand that an added party h ave the op portunity to respond before judgme nt is entered against him. Id., at 465–467. In a footnot e explainin gthat relation back does not deny th e added par t y an oppor t unity to re spond to th e amended pleading, we noted that the case di d not arise under the “mistake cl ause” of R u le 15(c): 4

### “Respondent Adams ma de no such mistake. It knew of Nelson’s role and existence and, until it movedto amend its pleading, chose to assert its claim for costs and fees only against [Nelson’s company].” Id

. , at 467, n. 1. Contrar yto respondent’s claim, Nelsondoes n o t suggest that Rule 15(c)(1)(C)(i i) cannot b e satisfied if a plaintiff k n ew of the prospective defendant’s existence at the time she filed her original complaint. In that cas e , there was nothing in the initialpl eading suggesting that Nelson was an intended part y, wh ile there was evidence in the record (of which Nelson was aware) th at Adams s o ught to a d d him only a f ter learnin gthat the company would not b e able to satisfy the jud g ment. Id., at 463–464. This evi

-

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4 The “mistake c l ause” at the time we dec i d e d Nelsonw a s set for t hin Ru le 15(c )(3). 529 U. S., at 4 67, n

. 1; 528F

. R. D. 525, 5 2 9(1 991). Ru le 15(c ) was r e n u m ber e d in2 007 with ou t s u bstan t iv e c h an g e“as par t of the general restyling of the Civil Rule s,” at which time it received it s cur r entpl a c e m enti nR u l e 1 5 (c)(1 )(C )(i i)

. A dvi s o ry C o m m i tt ee’s 2 007 Notes onFed

. Ru le Civ

. Pr oc . 15, 28 U. S. C. App., p. 37 (20 06 ed. , Supp. II).13 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### dence countered any implicat ion that Adam s had origi

nally failed to name Nelson becau s e of any “mistake co n cerning the proper pa rt y’s iden tity,” and instea d suggested that A d ams decided to name Nelson only afterthe fact i n an attempt to ensure that the fe e award would be paid. The footnote merely o b serves that Adams h a d originally been under no misimpression abo ut the function Nelson played in the underlying dispute. We said, after all, th at Adams kne wof Nelson’s “role” as well as his existence. Id., at 467, n. 1. Read in context, the footnote in Nelsonis entirely consistent with our understanding of the Rule: When the original complaint and the plain t iff’s conduct compel the conclusion that the f a ilure to name the pr o spective defendant in the original complaint was the resul t of a fully informed decision as op posed to a mistak e con cerning the proper defendant’s identity, the requirement s of Rule 15(c)(1)(C)(ii) are not met. This co nclusion is in keeping wi t hour rejec t ion toda y o f the Court of Appeals’ reliance on the plaintiff’s k n owledge to deny relation back

. B The Court of Appeals offered a second reason why Kru p ski’s amended complaint did not relate back: Krups k i had unduly delayed in seeking to file, and in eventually filing, an amended complaint. 330 Fed. Appx., a t895. The Court of Appeals offered no support for its view that a plaintiff’s dilatory cond uct can jus t ify the denial of relation back under Rule 15(c)(1)(C), and we find none. The R u le plainly sets forth an exclusive list of requirements for relation ba ck, 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 gra n t relation back to the district cou rt’s equitable discretion. See Rule 15(c)(1) (“An amendment

. . . rela t e sback

. . . when” the three listed requiremen t s are met (emphasis a d ded)).14KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### The mandatory natu r e of the inquiry for relation ba ck under Rule 15(c) is particularly striking in con trast to the inquiry un der Rule 1 5 (a), whichsets forththe circu m stances in which a party may a m end its pleading before trial. By its terms, Rule 15(a) gives discretion to th e district cou rt in deciding wh ether to grant a motion t o amend a pleading to a d d a party or a claim. Following an initial period after filing a pl eading during which a party may amend once “as a matter of course,” “apart y ma y amend its pleading only with the opposing pa rty ’s writte n consent or the court ’ s leave,” which the c o urt “should freely give .

. . when j u stice so requires.” Rules 15(a)(1 )– (2). We ha ve previous ly explained that a co urt ma y co n sider a movant’s “undue dela y” or “dilatory motive” in deciding whether to grant leave to amendunder Rule 15(a). Fom a nv. Da vis , 371 U. S. 178, 182 (1 962). As th e contrast be tween Rule 15(a) and Rule 15(c) makes clear, however, th e speed with which aplaintiff moves to amend her complaint or files an amended complaint after obtain

ing leave to do so h a s n o 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 exami n e a plain

tiff’s condu ct durin gt h e 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)(i i) is what the prospective defenda n t reasona

bly should have understood about the plaintiff’s intent i n filing the original complaint against the first defendant. To the extent the plaintiff’s postfiling conduct informs the prospective defendant’s understa n ding of whether th e plaintiff initially made a “mistake concerning the proper party ’s identity,” a court may consider the conduct. C f

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

filing event s occasional ly can shed light on th e plaintiff’s15 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### state of mind at an ea rlier time” and “can in form a defen

dant’sreasonable b e liefs concerning whether her omiss i on 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 Applyingt h ese principles to the facts of th is case, we think it clear that the courts below erred in denying rela

tion back under Rule 15(c)(1)(C)(i i). The Di strict Court held that Costa Croc iere had “ c onstructiv e notice” of Krups k i’s complaint within the Rule 4(m) period. App. to Pet. for Cert. 15a–17a. Costa Crociere has notchallenged this finding

. Because t h e complaint made cle a r thatKru p sk i meant to sue the company that “o wned, operated, managed, supervised and controlled” the sh ip on which she was inj u red, App. 23, and als o indicated (mistakenly) that CostaCruise performed those roles, id

. , at 23–27, Costa Crociere should have k n own, within the Rule 4( m) period, that it was not named as adefendant in that com

plaint only because of Krup s k i’s misunderstanding about which “ C osta” entity was in char ge of the ship—clearly a “mistake co ncerning th e proper party ’s identity.” Respondent contends that beca use the original com

plaint referred to th e tick et’s forum requirement and presuit claims notification procedure, Krupskiwas clearly aware of the contents of the tick et, and because the tick et identified Costa Crociere as the carrier and proper party

——————

5 S i m i la rly, we rej e ctres p ond e nt ’s s u gges t ion t h a tRule 1 5 (c) req u ires a plaint iff to mov eto ame n d herc o mpl a int orto file and serv e an amended com p laint within the Rule 4(m) period. Rule 15(c)(1)(C)(i) simplyr e quir es that the pr ospec t iv e defenda n tha s received s u fficient “notice of the action” wi thinthe Rule 4( m ) period that he will not be prejudiced in defending the case onthe m e r i ts. The Adv i sor yCommit

tee Notes to t h e 1966 Ame n dmen t c l ar ifyth at “th e n o tic en eed n o t b e for m al.” Adv i sor yCommitte e’ s 1966 No tes 122.16 KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### for a lawsuit, respondent was entitled to think that she made a deliberate choice to su e Costa Cruise instead of Costa Croc iere. Brief for Respondent 13. As we ha ve explained, however, that Krups k i may have known the contents of the ticket does n o t foreclose the possibility tha t she noneth eless m i sun d erstood crucial facts regarding the two compa n ies’ identities. Es pecially because the face of the complaint plainly i n dicated su ch a misun d erstanding , respondent’s contention is not persuasive. Moreover, respondent has articulated no strategy that it could rea

sonably have thought Kru p ski 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 compla int duringthe Rule 4(m) peri od shows that she made no mistake in that period. Id., at 13–14. But as discussed, any delay on Kru p ski’s pa rt 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 or iginally. Krupski’s failure to add Cost a Crociere during the Rule 4(m) period is not sufficient to make reasonable a n y belief t hat she ha d made a deliberate and informeddecision not to sue Cost a Crociere in the first instance. 6 

### Nothing in Krupski’s con

duct durin gthe Rule 4(m) period suggests th at she failed to name Costa Crociere because of anything other than a mistake. It is a l so worth noting that Costa Cruise and Costa

——————

6 The Court of Appeal s concluded that Krupski was not diligen t mer e lybec a u s e sh e did n o t seek leav e to add Cos t a Cr o c ier eun til 13 3 days af ter she filed her original comp l a intand di d not a c tually file an amen ded c o m p lain t foran ot h e ra mon t hafterth at. 330 Fed. Appx ., at 895. It is n o tc l earwh yKru p ski sh ou ld h av ebeenfou n ddilator yfo r nota ccept ing a tfa ce value t h e unpro v e nalleg a tion s in Cost a Cr u i se’ s a n s w er a n d corpora t e dis c los u re form

. In fa ct , Krup s k i m o ved t o amend herc o mplaint to ad d Costa Cr oc ier ewithin the time per i od pres crib e d b y t h e Dis t rict Court ’ s s c heduling order. See App. 3, 6–7; Record, Do c. 2 3 , p. 1.17 Cite as: 56 0 U

. S. ____ (2010) Opinion of theCourt 

### Crociere ar e related c o rporate entities with very simila r names; “crociera” even means “cruise” in Italian. Cassell’s Italian Dictionary 137, 670 (1967). This interrelationship and similarity heighte nthe expectation that Costa Croci

ere should suspect a mistak e has been made when Costa Cruise is n a med in acomplaint that actually describes Costa Croci e re’s activit i es. Cf. Morel v. Da imle r Chr ys le r AG , 565 F. 3d 20, 27 (CA1 2009) (where complaint con

veyed plain t iffs’ attempt to sue a u tomobile manufacturerand erroneously named the manufacturer as DaimlerChrysler Corporation instead of the actual manufacturer, a legally distinct but related entity named DaimlerChrys

ler AG, the latter should have realized it h a d not been named bec ause of pla i ntiffs’ mistake); Goodmanv. Prax air, Inc. , 4 94 F. 3d 4 58, 473–47 5 (CA4 2007) (en ba nc) (where complaint named parent company Praxair, Inc. , but describ e d status o f subsidiary compan y Praxair Ser

vices, Inc., subsidiary company knew or should have known it h a d not been named because of p l aintiff’s mis

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

uted to passenger confusion over “the proper party” for a lawsuit. The front of the ticketadvertises that “Cost a Cruises” has achieved a certifica tion of quality, App. to Pet. for Cert. 25a, without clarifying whether “Costa Cruises” is Costa Cruise Lin e s, Costa Crociere, or s o m e other related “Costa” c o mpany. I n deed, Costa Crociere i s evidently aware that the diffe rence between Costa Cruis e and Costa Crociere can be confus ing for cruise ship pas sengers. See, e.g., Suppav. Cos t a Crocie re, S. p. A. , No. 07–60526–CIV, 2007 WL 4287508, *1, (SD Fla., Dec. 4, 2007) (den ying Costa Crociere’s motionto dismiss the amended complaint where the original complaint had named Cos t a Cruise as a def e n d ant after “find[ing] i t simply inconceivable that De fendant Costa Crociere was not on notice .

. . that .

. . but for t h e mistake in the origi

nal Complaint, Costa Crociere was the appropriate party18KRUPSKI v. COSTA CROC I ERE S. P . A. Opinion of theCourt 

### to be named in the action”). In light of these facts, Costa Crociere should have known that Krups k i’s failure to na me it as a defendant in her original complaint was due to a mistake concerning the proper party’s identity. W e therefore reverse the judgment of the Court of Appeals for the Eleventh Circui t and remand the case for further proceedings consistent with this opinion. It is so orde red._________________

_________________ 1 Cite as: 56 0 U

. S. ____ (2010) Opinion of S CALIA , J. 

# SUPREME CO URT O FTHE UNI TED STATES

No. 09–3 37 

### WANDA KRUP SKI, P E TITION E R v. COSTA CROCIER E S. P 

### . A. ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEAL S FOR THE ELEV ENTH CIRC U I T [Ju n e7, 2010] 

### J USTICE 

### S CALIA 

### , concu rring in pa rt and conc urring i n the judgme nt. I join the Court’s opinion except fo r its relianc e, ante , a t 10–11, 15, n. 5, on the Notes of th e Advisory Committee as establishin gthe meaning of Fede ral Rule of Civil Proce

dure 15(c)( 1 )(C). The AdvisoryC o mmittee’s insights into the proper interpretati on of a Rule’s text are useful to the same extent as any scholarly commentary. But the Com

mittee’s intentionshave no effect on the Rule’s meanin g . Even assuming that we and the Congress that allowed t h e Rule to take effect read and agree dwith thos e intentions, it is the text of the R u le that controls. Tomev. Uni t ed Sta t es , 513 U. S. 150, 1 67–168 (1995) (S CALI A 

### , J., concur

ring in part and concurring in judgment).