On Appeal from the United States District Court for of Delaware (D.C. Civil No. 1:23-cv-01175) Chief District Judge: Honorable Colm F. Connolly

Argued October 1, 2025 Before: SHWARTZ, MATEY, and FISHER, Circuit Judges .

(Filed: May 18, 2026)

Miguel A. Estrada ARGUED Gibson Dunn & Crutcher 1700 M Street NW Suite 900Page 2 Washington, DC 20036

Alexandra Ewing Travis S. Hunter Richards Layton & Finger 920 N King Street One Rodney Square Wilmington, DE 19801

Rahim Moloo Jason W. Myatt Gibson Dunn & Crutcher 200 Park Avenue 47th Floor New York, NY 10166 Counsel for Appellant

Joshua D. Anders Andreas A. Frischknecht ARGUED James M. Hosking Chaffetz Lindsey 1700 Broadway, 33rd Floor New York, NY 10019

Henry E. Gallagher, Jr. Alan R. Silverstein Connolly Gallagher 1201 N Market Street, 20th Floor Wilmington, DE 19801 Counsel for Appellee

Page 3FISHER, Circuit Judge . In this action brought to confirm, recognize, and enforce a foreign arbitral award, Sociedad Concesionaria Metropolitana de Salud S.A. ( “ SCMS ” ) attempts to invoke quasi in rem jurisdiction over property that belongs to an arbitralaward debtor’s alleged successor in interest. Finding insufficient contacts between the forum, the successor in interest, and the underlying controversy, the District Court found no basis to exercise personal jurisdiction 1 and dismissed SCMS's petition. SCMS appeals. Because we agree with SCMS that Shaffer v. Heitner , 433 U.S. 186, 210 n.36 (1977), authorizes the exercise of traditional quasi in rem jurisdiction in an action to collect on an already adjudicated liability, we will vacate and remand.

In 2014, the Chilean Ministry of Public Works awarded a contract to Astaldi Concessioni S.R.L. to design, construct, and operate a new hospital project in Santiago, Chile. Later that year, Astaldi Concessioni S.R.L. assigned the contract to Page 4SCMS, a stand-alone Chilean company. In turn, SCMS contracted with Astaldi Sucursal Chile, the Chilean branch of Astaldi, S.p.A., an Italian company (together, “Astaldi”) , who assumed SCMS’s design and construction obligations. SCMS and Astaldi agreed to resolve any dispute in an arbitration proceeding before the Santiago Center for Arbitration and Mediation.

In September 2018, while the hospital project was under construction, Astaldi commenced in Italy a ' Concordato ” proceeding — a restructuring process akin to a proceeding commenced under Chapter 11 of the United States Bankruptcy Code —that restricted Astaldi’s paying of certain debts. SCMS determined that Astaldi could not timely complete the project, and in January 2019, SCMS terminated the contract. An arbitration ensued in Chile, which resulted in an award in favor of SCMS and against Astaldi.

During the arbitration proceeding, Astaldi completed the restructuring process by “ spinning off ” its operating business and merging into Webuild S.p.A., an Italian multinational construction company. Under the proposed “ spin-off ” transaction: (1) Astaldi would continue certain business activities, including construction and infrastructure projects; (2) Astaldi would liquidate some assets and issue new shares to satisfy unsecured creditors; and (3) Webuild would infuse 225 million Euros of capit al to compensate Astaldi's preferential creditors in exchange for majority control and ownership of Astaldi. A majority of Astaldi’s creditors approved the proposal, and an Italian court approved the restructuring plan in July 2020. On August 1, 2021, Webuild acquired the majority of Astaldi's business (namely, the “building, infrastructure construction, . . . the study, design, transportation, maintenance, facility management and operation of complex systems”), App. 291, which purportedly Page 5included the “assets and liabilities” of several projects, including the Santiago hospital project, App. 284. Under this agreement, “Astaldi’s business' would “continu e as a going concern, ” while “integrate[d] . . . within Webuild,” App. 279, and Astaldi’s “remaining assets” would 'continue their activities . . . for the exclusive benefit of' Astaldi's shareholders , App. 802. In other words, Astaldi, which is presently known as Astaris S.p.A., intended to liquidate and “wind down” each asset that was not acquired by Webuild.

In January 2022, Astaldi petitioned the Chilean Court of Appeals to set aside or modify the arbitral award. Finding that the arbitrator failed to apply a limitation of liability provision in the contract between SCMS and Astaldi, the Chilean Court of Appeals reduced the amount of damages but otherwise affirmed Astaldi’s obligations under the award. Astaldi appealed to the Chilean Supreme Court, which held that the Chilean Court of Appeals' decision was not subject to challenge and that Astaldi's appeal is 'inadmissible.' App. 205.

In the United States District Court for the District of Delaware, SCMS brought this action against Webuild to confirm, recognize, and enforce the final arbitral award under 9 U.S.C. § 207, the Federal Arbitration Act ( “ FAA ” ), which implements in the United States the Convention on the Recognition and Enforcement of Foreign Arbitral Awards, June 10, 1958, 21 U.S.T. 2517 ( “ New York Convention ” ). Trying to collect the arbitral award and alleging that Webuild is Astaldi’s successor in interest, SCMS attempted to invoke Court’s quasi in rem jurisdiction over Webuild’s shares in Webuild US Holdings, Inc., a Delaware-based and wholly owned subsidiary of Webuild.

Webuild moved to dismiss SCMS’s petition for lack of Page 6personal jurisdiction. Specifically, Webuild argued that Shaffer extends the minimum-contacts test of International Shoe Co. v. Washington , 326 U.S. 310, 322 (1945), to quasi in rem actions and that SCMS failed to establish minimum contacts between Delaware, the underlying breach-of-contract action, and Webuild US — who was a party to neither the arbitration nor the underlying contract. In response, SCMS argued that Shaffer 's thirty-sixth footnote expressly permits a court's exercising quasi in rem jurisdiction in an action to collect on an already adjudicated liability. Shaffer 's thirty-sixth footnote states:

Once it has been determined by a court of competent jurisdiction that the defendant is a debtor of the plaintiff, there would seem to be no unfairness in allowing an action to realize on that debt in a State where the defendant has property, whether or not that State would have jurisdiction to determine the existence of the debt as an original matter.

Shaffer , 433 U.S. at 210 n.36.

Finding no basis for personal jurisdiction, Court granted Webuild's motion and dismissed SCMS's petition. Sociedad Concesionaria Metropolitana de Salud S.A. v. Webuild S.p.A , No. CV 23-1175-CFC, 2024 WL 4333144, at *2 (D. Del. Sept. 27, 2024). First, Court held that Shaffer and its progeny categorically “preclude [] a court from exercising jurisdiction over a nonresident defendant based solely on the presence of property in the court’s state that is unrelated to the action.” Id . Finding that SCMS failed to allege a relation between Webuild US and the Chilean arbitration, Court found insufficient contacts to support the exercise of quasi in rem jurisdiction. Id . at *1 – 2. Second, Court alternatively held that, even if SCMS's interpretationPage 7 of Shaffer’s thirty-sixth footnote is correct, the 'exception' to Shaffer’s general rule does not apply to this action because SCMS did not ask the District Court to recognize a court of competent jurisdiction's determination that Webuild (as opposed to Astaldi) is SCMS’s debtor. Id . at *2. SCMS appeals each holding.

The District Court exercised subject matter jurisdiction under 9 U.S.C. § 203 and under 28 U.S.C. § 1331. We exercise subject matter jurisdiction under 28 U.S.C. § 1291. “We review Court’s dismissal for lack of personal jurisdiction de novo.' Danziger & De Llano, LLP v. Morgan Verkamp LLC , 948 F.3d 124, 129 (3d Cir. 2020). Because Court did not conduct an evidentiary hearing, SCMS's jurisdictional facts are accepted as true, and SCMS “ need only establish a prima facie case of personal jurisdiction. ” See, e.g. Metcalf v. Renaissance Marine, Inc. , 566 F.3d 324, 330 (3d Cir. 2009) (internal quotation marks omitted).

On appeal, SCMS challenges Court's primary and alternative holdings. With respect to the primary holding — that no basis for personal jurisdiction exists — SCMS contends that, under Shaffer 's thirty -sixth footnote, no minimum contacts are required for a court to exercise quasi in rem jurisdiction in an action to collect on an already adjudicated debt.Page 8 2 Therefore, the question is whether, in an action to collect on an already adjudicated debt, the mere presence of a debtor’s property within a forum state establishes a constitutional basis for which to exercise quasi in rem jurisdiction.

Personal jurisdiction is a court's authority to assert coercive power over a defendant. Historically, personal jurisdiction fell into one of three categories: one directs power over persons — in personam jurisdiction — and the other two direct power over interests in specific property — in rem and quasi in rem jurisdiction. Shaffer , 433 U.S. at 199; see also Hanson v. Denckla , 357 U.S. 235, 246 n.12 (1958). Each of these characterizations is a vestige of a time in which personal jurisdiction depended on territori al power: if a defendant's person or property was located within a state's geographic boundaries, a state court could exercise jurisdiction. Id. (“[U]nder Pennoyer [,] state authority to adjudicate was based on the jurisdiction’s power over either persons or property.”); Pennoyer v. Neff , 95 U.S. 714, 722 (1877) (explaining that personal jurisdiction rests on two “principles of public law”: (1) “every State possesses exclusive jurisdiction and sovereignty over persons and property within its territory,” and (2) “ no State can exercise direct jurisdiction and authority over persons or property without its territory,' i.e ., ' no tribunal established by [a state] can extend its process beyond that Page 9territory so as to subject either persons or property to its decisions”).

Each of the three categories describes the way in which a court may affect the interests or rights of a defendant. For example, an in personam judgment 'impose[s] a personal obligation on the defendant in favor of the plaintiff. ” Shaffer , 433 U.S. at 199. On the other hand, the effect of an in rem or quasi in rem judgment is “limited to the property that supports jurisdiction and does not impose a personal liability on the property owner, since he is not before the court.” Id . Accordingly, a defendant’s liability and a plaintiff’s possib ility of recovery are greater if a court exercises in personam jurisdiction over a defendant.³

Page 10Also, an in personam judgment provides a winning party with the possibility of interstate enforcement. An in personam judgment rendered in any state of the United States is entitled to full faith and credit in the courts of every sister state.⁴ As the Supreme Court explained, 'a debtor can[not] avoid paying his obligations by removing his property to a State in which his creditor cannot obtain personal jurisdiction over him. The Full Faith and Credit Clause, after all, makes the valid in personam judgment of one State enforceable in other States.” Shaffer , 433 U.S. at 210.

Quasi in rem jurisdiction comes in two types. Type I is used to determine the ownership of disputed property between two or more defined parties. Restatement (Second) of Judgments § 6 cmt. a (Am. Law Inst. 1982). Quasi in rem Page 11type I is most often used in “ actions to partition land, quiet title, or foreclose mortgages.' Linda J. Silberman, Shaffer v. Heitner : The End of an Era , 53 N.Y.U. L. Rev. 33, 39 (1978). Also, Quasi in rem type I is distinct from in rem jurisdiction because in rem jurisdiction determines ownership of property as against the entire world, but a quasi in rem judgment applies only to defined parties. Shaffer , 433 U.S. at 199 n.17 (citations omitted). Quasi in rem type II, the form of jurisdiction SCMS attempts to invoke here, involves the use of property not to determine ownership but to serve as the basis for litigation of some other dispute between the parties. Silberman, 53 N.Y.U. L. Rev. at 39; Restatement (Second) of Judgments § 8(1)(d) (Am. Law Inst. 1982). Under type II, the plaintiff concedes the defendant’s ownership of the attached property and uses that ownership as the basis for invoking jurisdiction. Shaffer , 433 U.S. at 199 n.17 (citations omitted).

In practice, quasi in rem jurisdiction type II, more commonly known as attachment jurisdiction, greatly expanded the reach of personal jurisdiction. Under this category, a court can exercise jurisdiction over a designated property and can render a judgment that affects only those interests of particular individuals in that property. Id . As relevant here, attachment jurisdiction is invoked to collect from the owner of the property a debt based on a judgment rendered in a forum where that owner was subject to personal jurisdiction. Id .; see also CME Media Enters. B.V. v. Zelenzy , No. 01 Civ. 1733 (DC), 2001 WL 1035138, at *3 (S.D.N.Y. Sept. 10, 2001) (“[Q]uasi in rem jurisdiction is used to attach property to collect a debt based on a claim already adjudicated in a forum where there was personal jurisdiction over the defendant.”). However, unlike an in personam judgment, '[t]he effect of a judgment in [an attachment jurisdiction] case is limited to the property that supports jurisdiction[;] . . . [the judgment] does not impose a Page 12personal liability on the property owner, since he is not before the court.” Shaffer , 433 U.S at 199.

Thus, historically, quasi in rem jurisdiction served both as a practical complement to in personam judgments and as a substitute for in personam jurisdiction. For most of our nation’s history, attachment jurisdiction allowed a creditor to adjudicate a claim against a fleeing debtor by attaching the property the debtor left behind. Michael B. Mushlin, The New Quasi in Rem Jurisdiction: New York’s Revival of a Doctrine Whose Time Has Passed , 55 Brook. L. Rev. 1059, 1066 – 67 (1990). Attachment jurisdiction provided to a creditor both a forum in which to adjudicate his claims against a debtor and a means with which to satisfy any resulting judgment. Id . For a time, attachment jurisdiction was considered “ indispensable. ” Robert Wyness Millar, Civil Procedure Of The Trial Court In Historical Perspective 481 (1952).⁵ Considering that 'huge sections of the continent were underdeveloped, and transportation and communication among its far flung parts remained primitive,” without attachment jurisdiction, a creditor would rarely have occasion to collect on a fleeing debtor’s debt. Mushlin, 55. Brook. L. Rev. at 1067.

As technology advanced and the New World became smaller, Pennoyer ’s framework began to fade. In response to the ever-increasing situations where a defendant caused injury in a state where in personam jurisdiction was lacking under Pennoyer , the Court modified the territorial limits on jurisdiction. See Shaffer , 433 U.S. at 202 (discussing the evolution of personal jurisdiction under Pennoyer ). Because these modifications produced inefficient processes that 'absorbed much judicial energy,' id ., the Court drastically shifted the focus of in personam jurisdiction from a court's territorial power over a person to the person’s contacts with the forum state, Int'l Shoe Co. , 326 U.S. 310 at 316 (“[D]ue process requires only . . . that the maintenance of the suit does not offend traditional notions of fair play and substantial justice.') (internal citation and quotation marks omitted). With respect to in personam jurisdiction, International Shoe abandoned Pennoyer ’s concern for states’ mutually exclusive sovereignty and mandated an inquiry into 'the relationship among the defendant, the forum, and the litigation.” Shaffer , 433 U.S. at 204.

However, in the three decades after International Shoe , '[n]o equally dramatic change . . . occurred in the law governing jurisdiction in rem [or quasi in rem ].” Id . at 205. Despite International Shoe 's abrogation of Pennoyer with respect to in personam jurisdiction, the traditional basis for quasi in rem jurisdiction, including attachment jurisdiction, persisted. Then came Shaffer . In that case, the Supreme Court extended International Shoe to all forms of personal jurisdiction, holding that an in rem action is consistent with the constitutional limits of due process only if the attached property is the subject of, or related to, the litigation. Id . at 212. In Shaffer , Heitner, a shareholder of the Greyhound Page 14Corporation, brought a derivative suit in Delaware against Shaffer and other members of the Greyhound board of directors. Id. at 189 – 90. According to Heitner, the board's unlawful actions subjected Greyhound to liability in a separate antitrust suit. Id. at 190. The alleged violations, however, occurred in Oregon, and none of the directors resided in Delaware. Id . 190 – 91. The directors were haled into Delaware court based on their ownership of stock and stock options that, according to Delaware law, were deemed present in Delaware. Id. at 191 – 94. But, as the Court noted, the “property [was] not the subject . . . of th[e] litigation, nor [was] the underlying cause of action related to the property.” Id . at 213. Indeed, the property was “completely unrelated to [the] cause of action . . . . [T]he only role played by the property [was] to provide a basis for bringing the defendant into court.” Id . at 209.

Concerned that the persistence of traditional in rem and quasi in rem jurisdiction undermined the theoretical basis of International Shoe , the Shaffer Court held: “if a direct assertion of personal jurisdiction over [a] defendant would violate the Constitution . . . an indirect assertion of that jurisdiction should be equally im permissible.” Id . Heitner could not have brought in Delaware an in personam action against the defendants because the alleged conduct did not relate to Delaware or to the defendants’ stock ownership. To permit the exercise of quasi in rem jurisdiction absent minimum contacts would circumvent the reasoning of International Shoe ; as Shaffer observes, “[t ]he phrase, ‘judicial jurisdiction over a thing’, is a[n] . . . elliptical way of referring to jurisdiction over the interest of persons in a thing.' Id . at 207 (quoting Restatement (Second) of Conflict of Laws § 56, Introductory Note (1971)).

Thus , when “the basis for . . . jurisdiction is completely unrelated to the plaintiff’s cause of action,” the mere presence of property within a particular state does not, by itself, support Page 15jurisdiction. Id. at 209. “The standard for determining whether an exercise of jurisdiction over the interests of persons is consistent with the Due Process Clause is the minimumcontacts standard elucidated in International Shoe .' Id . at 207. Therefore, in the context of a plenary action, Shaffer unequivocally holds that 'fair play and substantial justice' requires a sufficient relation between the property, the cause of action, and the forum. Id. at 211 – 12.

Despite Shaffer 's seemingly broad and unequivocal language, SCMS contends that Shaffer merely “introduce[s] a narrow constitutional limit” on traditional quasi in rem jurisdiction. Appellant ’ s Br. 21. SCMS argues that ' Shaffer extended International Shoe ’s minimum-contacts test to plenary actions that determine a defendant's initial liability . . . , but it left property-based jurisdiction in place for summary proceedings to enforce a previously adjudicated liability. ” Id. at 23. Specifically, SCMS identifies Shaffer ’s thirty-sixth footnote as creating this exception. Webuild responds that Shaffer establishes 'a categorical rule that a court’s exercise of quasi in rem jurisdiction is governed by the same, wellestablished 'minimum contacts' standard as in personam jurisdiction.” Appellee’s Br. 16. As to Shaffe r’s thirtysixth footnote, Webuild argues that no “court of competent jurisdiction” has determined that Webuild is liable for Astaldi's debt to SCMS. Appellee's Br. at 16 (quoting Shaffer , 433 U.S. at 210 n.36).

Although this is a question of first impression in this Page 16Court, 6 a few of our sister Circuits have considered the effect of Shaffer ’s thirty -sixth footnote, albeit without much explanation. The Ninth Circuit has invoked the footnote ’s reasoning and determined that a district court can exercise attachment jurisdiction in a post-judgment action without regard to minimum contacts. Glencore Grain Rotterdam B.V. v. Shivnath Rai Harnarain Co. , 284 F.3d 1114, 1127 (9th Cir. 2002) (recognizing that “[c]onsiderable authority supports [the petitioner’s] position that it can enforce the award against [the arbitral award debtor's] property in the forum even if the property has no relationship to the underlying controversy between parties'); Office Depot Inc. v. Zuccarini , 596 F.3d 696, 700 (9th Cir. 2010) (' In an action to execute on a judgment, due process concerns are satisfied, assuming proper notice, by the previous rendering of a judgment by a court of competent jurisdiction.”); Cerner Middle E. Ltd. v. iCapital, LLC , 939 F.3d 1016, 1022 (9th Cir. 2019) (holding that a district court may exercise quasi in rem jurisdiction when “(1) a court of competent jurisdiction rendered a judgment against [the defendant], and (2) [the defendant] owns property in the forum state”).

Similarly, the Second Circuit has endorsed the view that Shaffer permits a court to exercise attachment jurisdiction to confirm and enforce a foreign arbitral award. See Frontera Res. Azerbaijan Corp. v. State Oil Co. of Azerbaijan Republic , 582 F.3d 393, 398 (2d Cir. 2009) (holding that the district court did Page 17not err by requiring jurisdiction over the defendant’s person or property to enforce a foreign arbitral award). We agree with our sister Circuits. As explained below, Shaffer 's text expressly contemplates the continued existence of attachment jurisdiction in a post-judgment setting and that logic extends beyond enforcing a sister state’s judgment under full faith and credit to the enforcement of foreign judgments and foreign arbitral awards under the New York Convention.

First, Shaffer expressly acknowledged that the Due Process clause's fairness requirement is less stringent in an action to collect an already rendered judgment. Shaffer ’s thirty -sixth footnote provides the Supreme Court’s imprimatur of the practical relationship between in personam and attachment jurisdiction in post-judgment actions:

Once it has been determined by a court of competent jurisdiction that the defendant is a debtor of the plaintiff, there would seem to be no unfairness in allowing an action to realize on that debt in a State where the defendant has property, whether or not that State would have jurisdiction to determine the existence of the debt as an original matter.

Shaffer , 433 U.S. at 210 n.36. Contemplating the enforcement of a sister state's judgment under the Full Faith and Credit Clause, Shaffer 's thirty -sixth footnote embraces a rear-view mirror approach to personal jurisdiction: if the rendering court in one state properly exercised personal jurisdiction over the defendant, a court in a sister state may exercise traditional attachment jurisdiction to enforce the judgment. See Kulko v. Superior Court , 436 U.S. 84, 95 (1978) (holding that, although California’s a ssertion of personal jurisdiction over a New York resident was unreasonable, “a New York court would clearly Page 18have personal jurisdiction over [the defendant] and, if a judgment were entered by a New York court . . . , it could properly be enforced against him in both New York and California”). Thus, even after Shaffer , attachment jurisdiction persists as a complement to the enforcement of an in personam judgment.

Resisting this conclusion, Webuild characterizes Shaffer 's thirty -sixth footnote as “classic dicta” and argues that neither this Court nor the Supreme Court has adopted SCMS’s interpretation of Shaffer . Appellee’s . Br. 29. To support its argument, Webuild invokes two cases — Rush v. Savchuk , 444 U.S. 320 (1980), and Nehemiah v. Athletics Cong. of U.S. , 765 F.2d 42 (3d Cir. 1985) — each of which Court cited below. Both are inapposite.

In Rush , the plaintiff brought a negligence action in Minnesota against a non-resident defendant who injured the plaintiff in an automobile accident that occurred in Indiana. 444 U.S. at 322. Although the defendant had no contact with Minnesota, the defendant's i nsurer conducted business in Minnesota. Id . The plaintiff attempted to invoke the Minnesota court’s quasi in rem jurisdiction over the defendant by attaching the defendant's insurance provider's obligation to defend and indemnify the defendant. Id . Invoking Shaffer , Rush acknowledged that “the mere presence of property in a State does not establish a sufficient relationship between the owner of the property and the State to support the exercise of jurisdiction over an unrelated action.' Id . at 328. Because, among other reasons, the insurance policy was neither the subject matter of the cause of action nor related to the defendant's negligence, the Rush Court determined that no sufficient contacts existed between the litigation and the forum state. Id . at 329.

Like Court below, Webuild reads Rush to affirm that SPage 19haffer requires minimum contacts for all quasi in rem actions. But Rush merely interpreted Shaffer to say that a defendant’s in -state property alone cannot “support the exercise of jurisdiction over an unrelated cause of action.” Id . at 328. Rather unremarkably, Rush does nothing more than describe — and certainly does not expand — Shaffer 's basic premise: in a plenary action brought quasi in rem to adjudicate a liability unrelated to the in-forum property, minimum contacts are required. Rush does not mention, much less abrogate, Shaffer ’s thirty -sixth footnote, which addresses the jurisdictional requirements in a post-judgment action.

Similarly, Webuild invokes Nehemiah , which holds that “ the minimum contacts test [must] be used to evaluate the existence of all claims of in rem jurisdiction.” 765 F.2d at 47. In that case, we held that Shaffer 's 'sweeping language'that “‘ all assertions of state court jurisdiction must be evaluated according to the standards set forth in International Shoe and its progeny, ’” id. (quoting Shaffer , 433 U.S. at 212) — rendered unconstitutional the practice of so-called tag jurisdiction, which establishes jurisdiction over a non-resident defendant through in-state service, id. As SCMS notes, the Supreme Court abrogated our holding in Nehemiah and upheld the practice of tag jurisdiction . Burnham v. Superior Ct. of Cal. , 495 U.S. 604, 615 (1990) (plurality); see also Senju Pharm. Co., Ltd. v. Metrics, Inc. , 96 F.Supp.3d 428, 439 (D.N.J. 2015) (recognizing that Nehemiah “was cited by the Supreme Court in Burnham as one of the few opinions that have ‘erroneously’ found the practice of in-state service of process unconstitutional.” (quoting Burnham , 495 U.S. at 615)). Like Rush , Nehemiah did not involve an action brought to collect an already rendered judgment and did not discuss Shaffer 's thirty -sixth footnote.

In any event, the Supreme Court has cautioned litigants Page 20and lower courts against “(mis)reading Shaffer as suggesting that International Shoe discarded every traditional method for securing personal jurisdiction that came before.' Mallory v. Norfolk S. Ry. Co. , 600 U.S. 122, 141 (2023) (plurality) (upholding without regard to minimum contacts personal jurisdiction over a non-resident defendant corporation that consented to a state's general jurisdiction as a condition of conducting business within the state); see also Burnham , 495 U.S. at 622 (upholding without regard to minimum contacts tag jurisdiction). After all, the crux of both International Shoe and Shaffer is that due process requires compliance with “traditional notions of fair play and substantial justice.” Int’l Shoe , 326 U.S. at 316 (quoting Milliken v. Meyer , 311 U.S. 457, 463 (1940)). And according to Shaffer 's thirty -sixth footnote, 'there would seem to be no unfairness in allowing an action to realize on [an adjudicated] debt in a State where the defendant has property, whether or not that State would have jurisdiction to determine the existence of the debt as an original matter.” 433 U.S. at 210 n.36 (emphasis added).

Shaffer condemned '[t]he fiction that an assertion of jurisdiction over property is anything but an assertion of jurisdiction over the owner.' Id . at 212. In other words, Shaffer recognized that in a plenary action, “ quasi in rem jurisdiction, that fictional ‘ancient form,’ and in personam jurisdiction, are really one and the same and must be treated alike.” Burnham , 495 U.S. at 621 (discussing the holding of Shaffer ). But that is only where quasi in rem jurisdiction is invoked as a substitute, “ i.e ., [as] that form of in personam jurisdiction based upon a 'property ownership ’ contact.” Id .

In a post-judgment action, attachment jurisdiction is invoked merely to enforce an already adjudicated debt. The exercise of this kind of jurisdiction, like the nature of the cause of action, is fundamentally different than the exercise of in Page 21personam jurisdiction in a plenary action. See Titus v. Wallick , 306 U.S. 282, 291 (1939) (holding that, because the out-ofstate judgment, rather than the underlying cause of action, is the basis on which the judgment is sought, “the constitutional mandate requires credit to be given to a money judgment rendered on a civil cause of action in another state, even though the forum would have been under no duty to entertain the suit on which the judgment was founded”). Because the underlying cause of action merges into a judgment, a new and limited cause of action to collect on the judgment is created. Consequently, no justification exists to impose International Shoe 's litigation -relatedness requirement on a post-judgment proceeding. Shaffer ’s thirty -sixth footnote recognizes this commonsense exception and expressly preserves attachment jurisdiction in this limited circumstance.

Although attachment jurisdiction persists as a complement with which to enforce an in personam judgment, enforcing a judgment is not necessarily automatic. Under the Full Faith and Credit Clause, a court must recognize and enforce a sister state’s judgment only if the sister state’s court validly exercised personal jurisdiction over the parties. In other words, an in personam judgment rendered by a court that lacked personal jurisdiction is not entitled to another state’s full faith and credit. See World-Wide Volkswagen Corp. v. Woodson , 444 U.S. 286, 291 (1980) (“A judgment rendered in violation of due process is void in the rendering State and is not entitled to full faith and credit elsewhere.” (citing Pennoyer , 95 U.S. at 732 – 33)). Otherwise, a valid in personam judgment rendered by a sister state is subject only to the Page 22enforcing state’s bona fide procedural rules.⁷ See Baker ex rel. Thomas v. Gen. Motors Corp. , 522 U.S. 222, 235 (1998) (“Full faith and credit, however, does not mean that States must adopt the practices of other States regarding the time, manner, and mechanisms for enforcing judgments.”).

The Full Faith and Credit Clause and its implementing statute do not apply to foreign judgments or to foreign arbitral awards. Aetna Life Ins. Co. v. Tremblay , 223 U.S. 185, 190 (1912) (“N o such right, privilege, or immunity . . . is conferred by the Constitution or by any statute of the United States in respect to the judgments of foreign states or nations . . . .” ); McDonald v. City of West Branch , 466 U.S. 284, 288 (1984) ( 'Arbitration is not a 'judicial proceeding' and, therefore, § 1738 does not apply to arbitration awards.') . However, a similar mechanism exists for both foreign judgments and foreign arbitral awards. For example, a court will credit a Page 23foreign judgment to the extent that recognition comports with judicial comity. See Hilton v. Guyot , 159 U.S. 113, 202 – 03 (1895).⁸

More than a century ago, the Supreme Court recognized:

[Once] there has been opportunity for a full and fair trial abroad before a court of competent jurisdiction, conducting the trial upon regular proceedings, after due citation or voluntary appearance of the defendant, and under a system of jurisprudence likely to secure an impartial administration of justice between the citizens of its own country and those of other countries, and there is nothing to show either prejudice in the court, or in the system of laws under which it was sitting . . . or any other special reason why the comity of this nation should not allow it full effect, the merits of the case should not . . . be tried afresh . . . .

Id . Guided by this principle, state legislatures across the United States have enacted legislation to enable the recognition and Page 24enforcement of foreign judgments.⁹ Although courts are “qu ite liberal in their recognition and enforcement of foreign judgments,” Ronald A. Brand, Recognition and Enforcement of Foreign Judgments at 2 (Fed. Judicial Center April 2012), 10 a defendant may challenge the recognition and enforcement of a foreign judgment if the foreign court rendered the judgment under conditions that fail to satisfy basic requirements of due process, see, e.g. , Uniform Foreign Money-Judgments Recognition Act § 4(a)(1) (1962) (UFMJRA 1962); Uniform Foreign-Country Money Judgments Recognition Act § 4(b)(1) (2005) (UFMJRA 2005); Restatement (Third) Foreign Relations Law § 482(1)(a) (1986).

As with a judgment rendered by a sister state, if the rendering court lacked personal jurisdiction, the defendant may challenge the enforcement of the judgment in the enforcing court. UFMJRA 1962 § 4(a)(2); UFMJRA 2005 § 4(b)(2); Restatement (Third) Foreign Relations Law § 482(1)(b). In

[https://perma.cc/PE58-HV75] (last visited Mar. 26, 2026).

Page 25other words, the enforcement of foreign judgments in the United States complies with the constitutional requirements of due process in the same way that domestic counterparts do. For that reason, other courts have not limited the logic of Shaffer ’s thirty-sixth footnote to the enforcement of a sister state judgment under full faith and credit; if a foreign court properly exercised personal jurisdiction over a defendant, an enforcing court can exercise attachment jurisdiction over a defendant’s assets to enforce a foreign judgment. See, e.g. , Pure Fishing, Inc, v. Silver Star Co. , 202 F. Supp. 2d 905, 912 & n.3 (N.D. Iowa 2002) (holding that a court may recognize and enforce a foreign judgment against a judgmentdebtor’s property located in the state in the same manner that it would a judgment of a sister state); Electrolines, Inc. v. Prudential Assurance Co ., 677 N.W.2d 874, 885 (Mich. App. 2003) (same).¹¹

This begs the question: why should a court treat the enforcement of foreign judgments differently than the confirmation and enforcement of foreign arbitral awards? We do not find a principled reason to do so. Both the logic and spirit of Hilton and Shaffer ’s thirty -sixth footnote extend to the recognition and enforcement of a foreign arbitral award.¹²

First, the procedure to enforce a foreign arbitral award guarantees the protection of an award debtor 's due process rights. Of course, as mentioned above, arbitral awards are not subject to the Full Faith and Credit Clause and its implementing statute, which apply only to “judicial proceedings.” See McDonald , 466 U.S. at 287 (citation omitted). Because an “[a]rbitration is not a ‘judicial proceeding' . . . [,] § 1738 does not apply to arbitration awards.” Id . at 288. And unlike a foreign or domestic judgement, an arbitral award is not rendered by a judge. 13Page 27 Notwithstanding this fact, arbitrators resolve disputes. Mitsubishi Motors Corp. v. Soler Chrysler-Plymouth, Inc ., 473 U.S. 614, 626 (1985) (“By agreeing to arbitrate a . . . claim , a party does not forgo . . . [its] substantive rights . . . ; it only submits to their resolution in an arbitral, rather than a judicial, forum .”). An arbitration can provide just as fair a procedure as any judicial proceeding:

[S]hort of authorizing trial by battle or ordeal or, more doubtfully, by panel of three monkeys, parties can stipulate to whatever procedures they want to govern the arbitration of their disputes; parties are as free to specify idiosyncratic terms of arbitration as they are to specify any other terms in their contract.

Baravati v. Josephthal, Lyon & Ross, Inc ., 28 F.3d 704, 709 (7th Cir. 1994). If the parties agree to the terms of an arbitral clause, an arbitral award that results from arbitration is almost certainly fair.

This fairness is guaranteed by procedure. First, a party that agrees to arbitration consents to the jurisdiction of the arbitral tribunal and, to the extent that an arbitral award debtor Page 28resists recognition and enforcement to avoid confirmation, the debtor may furnish proof of one of the five affirmative defenses, including that the arbitration agreement is invalid “under the law of the country where the award was made.” 14 New York Convention, art. V(1)(a). As when a defendant resists the enforcement of a foreign or domestic judgment, the New York Convention and its implementing legislation ensure that the arbitral award debtor’s due process rights are protected.

Second, beyond adjudicating the narrow defenses described above, a court that confirms and enforces a foreign arbitral award has a very limited role. As with enforcement actions brought under the Full Faith and Credit Clause, petitions under the FAA to confirm foreign arbitral awards result in “summary proceeding s that do not require [a] district court to carry on a formal judicial proceeding.” Jiangsu Beier Decoration Materials Co. v. Angle World LLC , 52 F.4th 554, 560 (3d Cir. 2022) (internal citation omitted; alteration in original). And '[b ]y [requiring only] a truncated summary proceeding, the FAA directs district courts to give their imprimatur to arbitration awards by converting them into enforceable judgments.” Teamsters Loc. 177 v. United Parcel Serv. , 966 F.3d 245, 255 (3d Cir. 2020).

Only a summary proceeding is required because, like a judgment rendered by the court of a sister state, an unconfirmed arbitral award is the source of a new cause of action that is res judicata . Florasynth, Inc. v. Pickholz , 750 F.2d 171, 176 (2d Cir. 1984) (explaining that confirmation of an award is “a summary proceeding that merely makes what is Page 29already a final arbitration award a judgment of the court') ; Lynne Carol Fashions, Inc . v. Cranston Print Works, Co. , 453 F.2d 1177, 1179 (3d Cir. 1972) (“ [R]es judicata . . . operates to destroy causes of action by merger or bar”). This preclusive effect, although less forceful in this context, mirrors that of a domestic judgment and illustrates why attachment jurisdiction persists as a complement to, rather than a substitute for, in personam jurisdiction. And the fact that SCMS brings this proceeding to confirm and enforce a foreign arbitral award, rather than to adjudicate the underlying merits, “rightly colors our analysis.” Telcordia Tech Inc. v. Telkom SA Ltd ., 458 F.3d 172, 178 (3d Cir. 2006).

Finally, through the adoption and implementation of the New York Convention, Congress has unmistakably recognized an 'emphatic federal policy in favor of arbitral dispute resolution' that applies 'with special force in the field of international commerce' and that endorses 'the efficacy of arbitral procedures for the resolution of international commercial disputes.' Mitsubishi Motors , 473 U.S. at 631. Like the Full Faith and Credit Clause and its implementing statute that apply to the enforcement of a sister state judgment, and like the several state laws that apply to the enforcement of foreign judgments, the New York Convention imposes on United States courts an obligation to “recognize arbitral awards as binding and [to] enforce them.” New York Convention, art. III; 9 U.S.C. § 201 (providing that foreign arbitral awards rendered under the New York Convention “shall be enforced in United States courts'). Congress has enacted for foreign arbitral awards an enforcement scheme that closely resembles the Full Faith and Credit Clause and to which the logic of Shaffer 's thirty -sixth footnote comfortably extends.

Afterall, the concern that undergirds Shaffer 's thirty -

sixth footnote is that “a wrongdoer should not be able to avoid Page 30payment of his obligations by the expedient of removing his assets to a place where he is not subject to an in personam suit.” Shaffer , 433 U.S. at 210 (internal quotation marks omitted). This justification is no less relevant in permitting a court to enforce a previously rendered foreign arbitral award as it is in authorizing enforcement of a previously rendered judicial judgment. Holding otherwise would allow arbitral debtors to deliberately locate assets where courts would lack personal jurisdiction over them — an outcome that does not comport with 'fair play' or 'substantial justice.' Int’l Shoe , 326 U.S. at 316. Consequently, we join several other courts in holding that the logic of Shaffer ’s thirty -sixth footnote extends to an action to confirm and enforce an arbitral award under the New York Convention.¹⁵ See, e.g., Crescendo Mar. Co. v. Bank of Commc’ns Co. , No. 15 CIV. 4481 (JFK), 2016 WL 750351, at *5 (S.D.N.Y. Feb. 22, 2016) (discussing Shaffer in the context of confirming a foreign arbitral award and determining that '[a]lthough the Shaffer Court was referring to the enforcement of sister-state judgments under the Full Faith and Credit Clause of the Constitution, the same reasoning applies here”); Swiss Marine Servs. S.A. v. Louis Dreyfus Energy Servs. L.P. , 598 F. Supp. 2d 414, 420 n.5 (S.D.N.Y. 2008) (“This Court believes that the Shaffer rational [as articulated in its thirty-sixth footnote] would apply with equal force to the enforcement of foreign arbitral awards.”). Without regard to minimum contacts, a district court can exercise traditional attachment jurisdiction to enforce a foreign arbitral award. See CME Media Enters ., 2001 WL 1035138, at *3 (“Minimum contacts are not required because an arbitration panel with personal jurisdiction over [the defendant] has already adjudicated [the Page 31petitioner]’s claims against [the defendant] and determined that he is a debtor of [the petitioner]; the purpose of the instant proceeding is to collect on that debt.”). In other words, a court can exercise attachment jurisdiction based on the mere presence within the forum of an arbitralaward debtor's property, and the property does not need any relation to the underlying cause of action.

Shaffer 's thirty -sixth footnote does not preclude the

District Court from determining whether Webuild is Astaldi’s

successor in interest (and thus, the arbitral award debtor). The

District Court, assuming that Shaffer 's thirty -sixth footnote

creates an exception permitting a court to exercise traditional

attachment jurisdiction in a post-judgment action, alternatively

held that “[b]ecause [SCMS] has not asked me to recognize, let

alone enforce, in this action a determination by a court of

competent jurisdiction that Webuild is its debtor . . . such an

exception would not apply here.” Sociedad , 2024 WL

4333144, at *2. But, as we have now held, Shaffer 's thirty -

sixth footnote applies to enforcement of foreign arbitral

awards, not just court judgments. And nothing in ’s

thirty-sixth footnote precludes Shaffer Court from

determining whether Webuild assumed Astaldi's obligation

under the award. SCMS brought this action and alleged that

Webuild is Astaldi's successor in interest. In turn, Webuild

raised as an affirmative defense that Court lacked

personal jurisdiction. Once this defense is raised,

Court must first determine whether the defense is meritorious,

which includes considering evidence on the subject.

States v. Ruiz United , 536 U.S. 622, 628 (2002) ('[A] federal court

always has jurisdiction to determine its own jurisdiction.”).

successor in Court determines that Webuild is If Astaldi’s interest, then a “court of competent jurisdiction”Page 32 will have determined that 't he defendant is a debtor of the plaintiff .” Shaffer , 433 U.S. at 210 n.36.

The District Court has both the power and the obligation to determine whether Webuild is Astaldi's successor in interest. First, 'federal courts have a 'virtually unflagging obligation’ to exercise jurisdiction” where it exists. Rarick v. Federated Serv. Ins. Co. , 852 F.3d 223, 227 (3d Cir. 2017) (quoting Colo. River Water Conservation Dist. v. United States , 424 U.S. 800, 817 (1976)). A court must determine disputed jurisdictional facts, and this obligation extends as far as 'conduct[ing] a plenary trial on the contested facts,' if necessary, 'prior to making a jurisdictional determination.' Schuchardt v. President of the U.S. , 839 F.3d 336, 343 (3d Cir. 2016) (quoting Gould Elecs. v. United States , 220 F.3d 169, 177 (3d Cir. 2000)). Considering these principles together, because Court’s jurisdiction depends on whether Webuild is Astaldi’s successor in interest, Court has the power and the obligation to decide this question, regardless of how complex it may be.

Because the arbitrator already resolved the underlying controversy -SCMS's breach of contract claims against Astaldi — the only question left for the District Court to determine is whether Webuild is Astaldi’s successor in interest. To the extent that Webuild characterizes this issue as a merits question, it makes no difference. The obligation to determine jurisdiction remains, even when the “merits and jurisdiction . . . come intertwined.' Bolivarian Republic of Venezuela v. Helmerich & Payne Int’l Drilling C o. , 581 U.S. 170, 178 (2017). Successor jurisdiction applies in all jurisdictional contexts, including to a case where jurisdiction depends on minimum contacts and a case (like this one) where minimum contacts are not required. In re Nazi Era Cases Against German Defendants Litig. , 153 F. App ’ x 819, 824 (3d Cir. 2005) (minimum cPage 33ontacts); Patin v. Thoroughbred Power Boats Inc. , 294 F.3d 640, 649 – 55 (5th Cir. 2002) (waiver); Bunge S.A. v. Pac. Gulf Shipping (Singapore) Pte. Ltd. , No. 3:19-CV-00491-SB, 2020 WL 1528250, at *2 (D. Or. Mar. 31, 2020) ( quasi in rem ); cf. Transfield ER Cape Ltd. v. Indus. Carriers, Inc. , 571 F.3d 221, 224 (2d Cir. 2009) (“general alter ego principles . . . in the context of maritime attachments ” ); NYKCool A.B. v. Pac. Int ’ l Servs., Inc. , No. 12 CIV. 5754 LAK AJP, 2013 WL 6799973, at *10 (S.D.N.Y. Dec. 20, 2013) (finding general jurisdiction over the alter ego and/or successor in interest of judgment debtor that does business in the forum state). And Court may exercise personal jurisdiction over a successor in interest even if it would have lacked personal jurisdiction over the predecessor. See, e.g. , Gorton v. Air & Liquid Sys. Corp. , 303 F. Supp. 3d 278, 301 (M.D. Pa. 2018); In re DES Cases , 789 F. Supp. 552, 591 (E.D.N.Y. 1992). By failing to first determine whether Webuild is Astaldi’s successor in interest, the District Court erred.

We decline SCMS’s invitation to decide on appeal for the first time the complex, heavily factual successor-in-interest question. “When a district court has failed to reach a question below that becomes critical when reviewed on appeal, an appellate court may sometimes resolve the issue on appeal rather than remand to the district court.” Hudson United Bank v. LiTenda Mortg. Corp. , 142 F.3d 151, 159 (3d Cir. 1998). Generally, this procedure is “ appropriate when the factual record is developed” and the issue is purely legal. Id. Here, the factual record is developed but not in the manner that Hudson contemplates. This record is “developed” in the sense that it is enormous: the parties submitted more than 150 pages of briefs and expert declarations, along with hundreds of pages of exhibits, devoted solely to whether Webuild assumed liability Page 34for the award. App. 41 – 362, 367 – 844. However, Webuild’s status as successor in interest likely requires delving into several underlying complexities, including whether Delaware or Italian law applies, the relation between the Italian Concordata and the Chilean arbitration, and the niceties of a multi-billion-dollar two-step merger and spin-off transaction that occurred in Italy. Therefore, the District Court should resolve this question in the first instance. See Gov’t of Virgin Islands v. Martinez , 780 F.2 d 302, 310 (3d Cir. 1985) (“It is not our role to find facts and resolve factual issues at the appellate level.”).

For these reasons, we will vacate Court’s dismissal for lack of personal jurisdiction and remand to Court to determine whether Webuild is Astaldi's successor in interest and to conduct any other proceedings consistent with this opinion.