                              In the

United States Court of Appeals
                For the Seventh Circuit
                           ____________

Nos. 06-4409, 08-1013

C HARLES A. C RAIG and B ARBARA J. C RAIG ,

                                                 Plaintiffs-Appellees,
                                  v.

O NTARIO C ORPORATION,
                                               Defendant-Appellant.
                           ____________
             Appeals from the United States District Court
      for the Southern District of Indiana, Indianapolis Division.
         No. 1:05-cv-861-LJM-JMS—Larry J. McKinney, Judge.
                           ____________

    A RGUED M AY 16, 2008—D ECIDED S EPTEMBER 10, 2008
                           ____________



  Before B AUER, P OSNER, and W OOD , Circuit Judges.
  W OOD , Circuit Judge. Charles Craig worked for Ontario
Corporation and participated in its employee stock
option plan. Under the plan, he was entitled to transfer
some of the shares of the stock he acquired to his wife
Barbara, and he did so. The plan also provided for a
bonus distribution of stock shares upon the participant’s
retirement. When Craig retired in 2001, he offered to
2                                    Nos. 06-4409, 08-1013

sell his shares back to Ontario. Ontario accepted, but it
paid with three promissory notes rather than cash.
  By their terms, these notes were subject to “Standby and
Subordination Agreements,” which subordinated the
Craigs’ rights to those of certain senior creditors (Fifth
Third Bank and First Merchants Bank). By December 2003,
Ontario was facing difficulties in meeting its financial
obligations. Eventually it reached an agreement with the
Craigs to suspend principal payments until December
2004. The agreement was not renewed, however, and the
Craigs sent Ontario a notice of default and sued in the
district court for the Southern District of Indiana, to
recover on the notes. They contended that their case
fell within the district court’s diversity jurisdiction,
under 28 U.S.C. § 1332(a) and (c).
  The Craigs were not the only creditors trying to get
money from Ontario. Fifth Third sent Ontario a notice
of default; that claim was settled in June 2006. First Mer-
chants also asserted that Ontario had defaulted on its
notes, but as of the time this case reached the district
court, its claim was still outstanding.
  The district court entered judgment for the Craigs on
the notes, stating that even though the terms seem to
prevent any payment to them, they do not bar the Craigs
from reducing their claim to judgment. The district court
denied a motion for relief from judgment by Ontario
in November 2006, and the first appeal before us (No.
06-4409) challenges that ruling.
  Subsequently, however, Ontario discovered facts that
draw the district court’s subject-matter jurisdiction into
Nos. 06-4409, 08-1013                                      3

question. It appears that the parties may not be of diverse
citizenship. Ontario moved under F ED. R. C IV. P. 60(b)(4)
for relief from the judgment on this basis (its second
motion under Rule 60, but that detail is unimportant for
our purposes), but the district court held that it had no
jurisdiction to rule on the motion because the case was
before this court on appeal. The court further held that
it had no jurisdiction even to conduct a hearing or to
review new filings while the appeal was pending. That
ruling led to a second notice of appeal, No. 08-1013,
which we have consolidated for disposition with the
first one.
  Naturally, the first question we must confront is that of
jurisdiction. Here we pause to note an oddity in the
jurisdictional statement that the Craigs filed in their
brief before this court. Appellant Ontario, which is con-
testing jurisdiction, asserts in its jurisdictional statement
that the Craigs had said at the outset of the litigation
that they were “residents” of Arizona, and that Ontario
is an Indiana corporation with its principal place of
business in Indiana. In fact, Ontario continues, it has
uncovered facts leading it to believe that the Craigs are
citizens of Indiana. It thus challenges the authority of the
federal courts to hear this case at all. When we looked to
the Craigs’ brief to see what response they had, all we
found was that they “state that the Jurisdictional State-
ment in Appellant’s Brief is complete and correct.” This
seemed like a concession either that the requirements
of diversity jurisdiction have not been satisfied, or at a
minimum a concession that a hearing is necessary to get
to the bottom of this.
4                                      Nos. 06-4409, 08-1013

  Whether or not there was such a concession, Ontario
is correct that the facts relating to subject-matter juris-
diction must be explored here. The district court was
mistaken that it had lost all authority to do so when the
motion under Rule 60(b)(4) was presented to it. We there-
fore vacate the court’s judgment on the merits in No.
06-4409 and reverse the court’s order denying the Rule
60(b)(4) motion in No. 08-1013 and remand for an eviden-
tiary hearing on subject matter jurisdiction.


                              I
   After an appeal has been filed, the district court may
still consider a motion for relief from judgment under F ED.
R. C IV . P. 60(b). See Graefenhain v. Pabst Brewing Co., 870
F.2d 1198, 1211 (7th Cir. 1989). In general, if the motion
lacks merit, the court should rule promptly and deny it;
if the court finds some merit, it should issue a short
memorandum so that the court of appeals can be in-
formed of its views and take appropriate action. See 7 TH
C IR. R ULE 57; Boyko v. Anderson, 185 F.3d 672, 675 (7th Cir.
1999).
  Here, the district court declined to express any tentative
view of the merits. It explicitly disclaimed jurisdiction “to
conduct a hearing or to review new filings while this
matter pends on appeal.” The Craigs somehow find in
this statement an indication that the district court thought
that it did have jurisdiction over the case and was intimat-
ing a negative view of the motion, but we see nothing of
the sort. The district court was aware of Boyko, but it
thought that Boyko was limited to habeas corpus proceed-
Nos. 06-4409, 08-1013                                         5

ings. The wording of Boyko does not, however, support any
such limitation; in fact, Boyko cites a wide variety of cases
for the proposition that a district court has jurisdiction
to consider or deny, but not grant, a Rule 60(b) motion. See
id. at 675 (collecting cases and discussing the best proce-
dure); see also Bronisz v. Ashcroft, 78 F.3d 632 (7th Cir. 2004)
(applying Boyko in immigration context); Williamson v.
Indiana University, 345 F.3d 459 (7th Cir. 2003) (mentioning
“the procedure we approved in Boyko” in an employment
case).
  This limited power is all the more important when
subject-matter jurisdiction is at stake. “[I]t has been the
virtually universally accepted practice of the federal
courts to permit any party to challenge or, indeed, to
raise sua sponte the subject-matter jurisdiction of the
court at any time and at any stage of the proceedings.”
Sadat v. Mertes, 615 F.2d 1176, 1188 (7th Cir. 1980). The
Federal Rules of Civil Procedure are no less insistent: “If
the court determines at any time that it lacks subject-
matter jurisdiction, the court must dismiss the action.” FED.
R. C IV. P. 12(h)(3). Subject-matter jurisdiction is so
central to the district court’s power to issue any orders
whatsoever that it may be inquired into at any time, with
or without a motion, by any party or by the court itself. The
order denying Ontario’s second motion for relief was
therefore in error, and the district court should have
taken up the issue.
6                                       Nos. 06-4409, 08-1013

                              II
   The only thing that might have justified the court’s
decision to pass on the jurisdictional challenge is if On-
tario’s showing were so inconsequential as to be frivolous.
But it was not. Indeed, as we understand the proffered
facts, there is a serious jurisdictional problem here. On
Ontario’s side, the facts that originally were alleged are not
contested: it is an Indiana corporation with its principal
place of business in Indiana. Matters are far less clear on
the Craigs’ side. They claim to be “residents” of Ari-
zona—an inadequate jurisdictional claim to begin with,
as we repeatedly have reminded litigants and district
judges, see, e.g., Camico Mut. Ins. Co. v. Citizens Bank, 474
F.3d 989, 992 (7th Cir. 2007); Meyerson v. Harrah’s East
Chicago Casino, 299 F.3d 616, 617 (7th Cir. 2002); McMahon
v. Bunn-O-Matic Corp., 150 F.3d 651, 653 (7th Cir. 1998). But
even if they had properly alleged that they were citizens
of Arizona, they are in trouble. Ontario presented evi-
dence that they may in fact be citizens of Indiana.
  It was not until the Craigs began efforts to collect on their
judgment that Ontario discovered some disturbing pieces
of evidence. It correctly presented this information to
the district court in its second motion for relief:
•   The 2005 and 2006 property tax records for the Craigs’
    property in Arizona—which was used to allege their
    residence there—listed an Indiana address in the
    “taxpayer information” section.
•   The Craigs purchased a second Indiana property (the
    “Wentworth Property”) right before filing their com-
    plaint (February 2005), and sold another one (the
Nos. 06-4409, 08-1013                                        7

    “Hickory Hills Property”) right after filing the com-
    plaint (July 2005).
•   Barbara Craig has remained registered to vote in
    Indiana, and did so in person in 2006. Under Indiana
    law, a person must be resident in a precinct for 30 days
    prior to the election in order to vote there, IND. C ODE
    § 3-7-13-1, and if a voter moves to another state with
    the intention to establish residency there, then he
    or she is no longer considered an Indiana resident
    for voting purposes, IND. C ODE § 3-5-5-8.
•   In April 2005, the Craigs received the Indiana home-
    stead tax credit for the Wentworth Property, which
    they continued to receive in 2006 and 2007. For the
    purposes of the credit, a homestead is “an individual’s
    principal place of residence which . . . is located in
    Indiana . . . .” IND. C ODE § 6-1.1-20.9-1(2). Before 2005,
    the Craigs had received the homestead credit on the
    Hickory Hills Property. Principal place of residence,
    or domicile, is central to determining citizenship. See
    Galva Foundry Co. v. Heiden, 924 F.2d 729, 730-31 (7th
    Cir. 1991).
All of these facts call into question the Craigs’ citizenship,
which is their burden to prove as the litigants claiming
the right to the federal forum. They complain that the
jurisdictional criticisms were not supported by admissible
evidence, but this puts the shoe on the wrong foot: the
Craigs, as the plaintiffs, have always had the burden of
proving federal jurisdiction. They cite many cases requir-
ing a heightened showing for a Rule 60(b) motion, but in
all of those the Rule 60(b) movant also had the burden
of proof on the issue raised. Where jurisdiction is in
8                                     Nos. 06-4409, 08-1013

question, the party asserting a right to a federal forum
has the burden of proof, regardless of who raises the
jurisdictional challenge and who presents the motion
under Rule 60(b). See Grafon Corp. v. Hausermann, 602 F.2d
781, 783 (7th Cir. 1979). Ontario has raised a serious
question about the Craigs’ true citizenship at the time
this case was filed (June 8, 2005), and the Craigs now
have the obligation to respond.
  The Craigs’ last argument is a curious one. Perhaps not
understanding the fundamental importance of subject-
matter jurisdiction or the ban on advisory opinions, they
contend that this court should reach the merits even if it
decides to remand the case to the district court for a
hearing on jurisdiction. They think that Brown v. United
States, 976 F.2d 1104 (7th Cir. 1992), supports this
method of proceeding. But it does not; Brown was a case
in which a taxpayer, faced with the prospect of being
whipsawed by different creditors after losing to one on
summary judgment, moved for relief under Rule 60(b). All
the court did was to rule on Brown’s appeal from the
underlying judgment and remand the Rule 60(b) mat-
ter—which had nothing to do with subject-matter juris-
diction—to the district court. Nothing in Brown indicated
that subject-matter jurisdiction could or should be treated
the same way. The challenge presented here goes directly
to the district court’s fundamental power to hear the
case at all: if the parties are not diverse, then an entirely
different sovereign will be adjudicating the case.
   Enough of a challenge to the district court’s power to
adjudicate was presented that it should have assured
itself that its jurisdiction was proper. We therefore
Nos. 06-4409, 08-1013                                       9

remand the case for an evidentiary hearing on the question
whether the parties are properly diverse. At this hearing,
the Craigs bear the burden of proving that they were
citizens of Arizona at the time the suit was filed.


                             III
  As a final note, we observe that several thorny issues
may arise once the question of citizenship is opened up.
What happens if Charles Craig is properly diverse, but
Barbara Craig is not? She is named on some of the notes,
but it is not clear whether she is a party who must be
joined. Another complication arises from the fact that
Arizona is a community property state, but Indiana is
not. It is possible, even if Charles Craig turns out to be a
citizen of Arizona and Barbara Craig has remained a
citizen of Indiana, that a non-diverse party may have a one-
half interest in the notes.
   These are questions that the district court must answer
first. Ontario properly called the problem to the district
court’s attention, and the court had the power to con-
sider the motion under Rule 60(b), even though an appeal
had already been filed. Indeed, it is under a continuing
obligation to assure itself of subject-matter jurisdiction, no
matter how the issue is raised. We V ACATE the judgment
on the merits in No. 06-4409, REVERSE the denial of On-
tario’s second Rule 60(b) motion in No. 08-1013 and
R EMAND for further proceedings in accordance with
this opinion.


                            9-10-08
