Madelyn Marina Quiroz, et al. v. Eduardo Hernandez, et al.

Federal Rule of Civil Procedure 15(c)(1)(C) provides that an amendment naming a new defendant relates back to the original pleading if, "within the period provided by Rule 4(m)," the newly named defendant received notice of the action and "knew or should have known that the action would have been brought against it, but for a mistake concerning the proper party’s identity." In Krupski v. Costa Crociere S.p.A., 560 U.S. 538 (2010), this Court held that the relation back turns on what the newly named defendant knew or should have known during that period — not on the plaintiff ’s knowledge or diligence. The question presented is whether Rule 15(c)(1)(C)(ii)'s mistake requirement may be denied because the prospective defendant is a legally distinct entity bearing a dissimilar name and was added rather than substituted—or whether, as Krupski holds, that inquiry turns on what the prospective defendant knew or should have known within the Rule 4(m) period about whether its omission resulted from a mistake concerning the proper party's identity.