                               In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
Nos. 14-3726, 14-3737
MICHELS CORPORATION,
                  Plaintiff-Counterclaim Defendant-Appellant,
PIPE LINE CONTRACTORS ASSOCIATION,
                               Intervening Plaintiff-Appellant,

                                 v.

CENTRAL STATES, SOUTHEAST, AND SOUTHWEST AREAS PENSION
FUND, et al.,
                 Defendants-Counterclaim Plaintiffs-Appellees.
                    ____________________

        Appeals from the United States District Court for the
          Northern District of Illinois, Eastern Division.
           No. 12-cv-4144 — Charles R. Norgle, Judge.
                    ____________________

     ARGUED JUNE 5, 2015 — DECIDED SEPTEMBER 2, 2015
                 ____________________

   Before WOOD, Chief Judge, and FLAUM and EASTERBROOK,
Circuit Judges.
   WOOD, Chief Judge. This case raises a familiar problem for
pension funds: when did an employer’s obligation to contrib-
ute to the fund end? That question turns on when the govern-
ing collective bargaining agreement (CBA) between a multi-
2                                        Nos. 14-3726, 14-3737

employer group and a union terminated and how one should
characterize a series of temporary “extensions” of the CBA.
Several common issues are not before us: we are not con-
cerned with withdrawal liability on the part of the employer;
we are not concerned about any possible duty to arbitrate con-
tested points; and in the end (despite considerable attention
to the point in the briefs) the standard of review does not mat-
ter.
    Cutting through the clutter, we conclude that the parties
to the CBA in question terminated it in accordance with its
terms effective January 31, 2011. Thereafter, the union and the
employer group entered into a series of short-term agree-
ments that had the effect of extending the CBA’s terms for the
designated periods while the parties negotiated. The interim
agreement that took effect on November 15, 2011, however,
was different: it eliminated the employers’ duty to contribute
to the pension fund and extended all other terms of the CBA.
The district court held that this was not sufficient to end the
employers’ duty to contribute and thus granted summary
judgment for the pension fund. We reverse. The CBA impos-
ing the duty to contribute had long since expired by Novem-
ber of 2011, and there was nothing to prevent the parties from
agreeing to the new arrangement.
                               I
   Michels Corporation is a pipeline construction company
based in Brownsville, Wisconsin. It is a member of the Pipe
Line Contractors Association (PLCA), a trade association that
(among other things) negotiates collective bargaining agree-
ments on behalf of its employer members with the relevant
unions—in this case, the International Brotherhood of Team-
Nos. 14-3726, 14-3737                                         3

sters (the Union). The Central States, Southeast, and South-
west Areas Pension Fund (the Fund) is a multiemployer pen-
sion plan. See 29 U.S.C. § 1000(2), (3), and (37). A board of
trustees, half of whom are appointed by contributing employ-
ers and the other half by the unions representing the plan par-
ticipants, runs the Fund.
    In February 2006, the PLCA and the Union entered into a
collective bargaining agreement known as the National Pipe-
line Agreement (the 2006 CBA). Article XV(C) of the 2006
CBA addressed the duration of the agreement; it stated that
“[t]he provisions of this Agreement shall continue in full force
and effect until January 31, 2011, and thereafter from year to
year unless terminated at the option of either party after sixty
(60) days’ notice in writing to the other.” Schedule A of the
2006 CBA laid out the timing and amount of contributions
that participating employers needed to make to the Fund.
Schedule B of the 2006 CBA, called the National Pipeline Par-
ticipation Agreement, spelled out the relationship among the
employers, the Union, and the Fund. It included the following
language:
   NOW, THEREFORE, IT IS AGREED by and between
   the undersigned Employer and the [Union] that such
   Employer hereby subscribes to the various agreements
   and declarations of trust and policies and procedures
   of the particular funds into which such Employer will
   be required to make contributions pursuant to the Na-
   tional Pipe Line Agreement, and agrees to be bound
   thereby and to amendments made or to be made
   thereto; and authorizes the parties to such trust agree-
   ments to name the trustees and successor trusts, and to
4                                        Nos. 14-3726, 14-3737

    administer the trusts; and does hereby ratify and ac-
    cept such trustees and the terms and conditions of said
    trusts as fully and as completely as if made by the un-
    dersigned Employer; provided, however that no
    amendments or provisions of said trust agreements
    shall bind the Employer for any financial obligations
    or dues delinquency determinations beyond that set
    forth in the National Pipe Line Agreement pursuant to
    which such contributions are made.
    On August 9, 2010, in compliance with Article XV(C), the
PLCA informed the Union that it intended to terminate the
2006 CBA on January 31, 2011, and begin negotiations for a
new agreement. Just before the end of January, however, the
parties signed a letter agreement extending the terms of the
2006 CBA for one month, to February 28, 2011. This proved to
be the first of eight such extensions; the last one extended the
2006 CBA’s terms from September 1, 2011, to November 15,
2011. Consistently with the obligations in the 2006 CBA and
the commitments in the letter agreements to continue operat-
ing under the 2006 CBA’s provisions, Michels continued to
contribute to the Fund throughout those extensions.
    The day before the eighth extension expired, the parties
shifted course. They agreed that the employers would cease
making contributions to the Fund as of November 15, 2011;
that they would make comparable payments to an escrow
fund until a fund “mutually acceptable to the Parties” was
designated; and that they would otherwise extend the terms
of the 2006 CBA until December 31, 2011. The pertinent lan-
guage of the November 15, 2011, agreement, which figures
prominently in this appeal, is as follows:
Nos. 14-3726, 14-3737                                        5

        AMENDMENT TO AND EXTENSION OF
      COLLECTIVE BARGAINING AGREEMENT
       BETWEEN PIPE LINE CONTRACTORS
     ASSOCIATION AND THE INTERNATIONAL
         BROTHERHOOD OF TEAMSTERS
      WHEREAS, the current National Pipe Line Agree-
   ment (“CBA”) between the Pipe Line Contractors As-
   sociation and … the [Union], as previously extended,
   expires at midnight, November 15, 2011;
      WHEREAS, the Parties have reached agreement
   that the PLCA may cease all contributions to the
   [Fund];
      WHEREAS, agreement on certain other issues has
   not been reached;
       WHEREAS, the Parties wish to give formal notice
   of this decision to [the Fund] in order to preclude any
   contention by [the Fund] that one or more members of
   PLCA has an obligation to contribute to [the Fund] un-
   der the Agreement for any period after November 15,
   2011;
      ...
      NOW, THEREFORE, BE IT:
      ...
     RESOLVED THAT, Section 1(a) of Article V of the
   CBA shall be amended to read as follows:
      (a) … [A]s of November 16, 2011, no Employer
          shall have an obligation to contribute to [the
          Fund]. The amount of those pension contribu-
6                                        Nos. 14-3726, 14-3737

          tions, as well as the amount of all pension con-
          tributions on behalf of Travelers, shall be made
          to a plan or plans mutually acceptable to the
          Parties. Until the Parties agree upon a mutually
          acceptable plan or plans, all funds that would
          otherwise be remitted to [the Fund] shall be
          held in escrow.
    On November 15, 2011, PLCA sent a copy of the Novem-
ber 15 agreement to the Union, which signed it. The next day,
Michels sent a letter to the Fund notifying it that Michels was,
pursuant to the November 15 agreement, terminating its con-
tributions to the Fund effective immediately. The PLCA sent
a similar letter the same day. Its letter added: “For obvious
reasons, it is imperative that the termination date of each
member’s contribution obligations be effective prior to De-
cember 31, 2011. This date means the members have less than
45 days to address any objection with the notice of termina-
tion you may choose to raise.” (PLCA believed that its with-
drawal liability would be significantly higher if the with-
drawal was not effective until after the end of calendar year
2011; that issue fell by the wayside and is not relevant to this
appeal.)
    The PLCA followed up with several letters to the Fund
sent between November 28, 2011, and the end of the calendar
year. These letters each asked if PLCA’s members (including
Michels) needed to take any further action to ensure that the
divorce from the Fund was effective. The Fund did not re-
spond until January 30, 2012, when it informed the Union that
the Fund had determined that none of the PLCA members ef-
fectively withdrew during 2011 because none of the letters
from the PLCA and Michels “was effective to terminate any
Nos. 14-3726, 14-3737                                        7

of the PLCA members’ obligations to contribute to the Fund.”
The PLCA and the Union concluded a new collective bargain-
ing agreement at the end of May 2012. The Fund received
written notice of this agreement on October 9, 2012. No one
disputes that no later than that date, Michels and the other
PLCA employers had withdrawn from the Fund.
    Meanwhile, on March 15, 2012, Michels initiated a lawsuit
seeking a declaratory judgment that its duty to contribute to
the Fund ended on November 15, 2011. The Fund filed its
amended counterclaim on August 2, 2012. The district court
had jurisdiction over both Michels’s complaint and the com-
plaint filed by PLCA (which intervened in the district court)
under 28 U.S.C. § 1331 and Section 301 of the Labor Manage-
ment Relations Act (LMRA), 29 U.S.C. § 185. It had jurisdic-
tion over the Fund’s counterclaim under 28 U.S.C. § 1331 and
Section 502(e)(1) of the Employee Retirement Income Secu-
rity Act (ERISA), 29 U.S.C. § 1132(e)(1).
   On cross-motions for summary judgment, the district
court ruled in favor of the Fund and against Michels and
PLCA. Using numbers to which the parties had stipulated, it
held that Michels had to pay the Fund $895,565.48 for the
principal contributions it owed from November 2011 until
October 2012 and $336,670.96 for interest, statutory damages,
and fees. The court entered its final judgment on December 2,
2014; it re-entered the judgment two days later to make a tech-
nical correction to the caption of the case. Michels and PLCA
both appealed.
                              II
8                                         Nos. 14-3726, 14-3737

    Before we move to the main event, we offer a word about
standard of review, to explain why we do not consider it dis-
positive here. We then address the question whether the 2006
CBA remained in full effect by virtue of the numerous exten-
sion agreements that were concluded, or if it terminated and
each extension agreement functioned as an interim CBA be-
tween PLCA and the Union. If the former is the case, as the
district court thought, then the parties had no right to elimi-
nate the contribution obligation in the November 15, 2011,
agreement. If the latter is the better characterization, then the
obligation to contribute died no later than November 15, 2011,
when the parties eliminated it in a written agreement and
communicated that agreement to the Fund.
                               A
    Michels and PLCA argue that this court should approach
the dispute unencumbered by any deference to the Fund’s po-
sition; they stress that we are reviewing a grant of summary
judgment, and de novo review typically applies in that situa-
tion. Orr v. Assurant Employee Benefits, 786 F.3d 596, 600 (7th
Cir. 2015). The Supreme Court held in Firestone Tire and Rubber
Co. v. Bruch, 489 U.S. 101 (1989), that in actions challenging
denials of benefits based on plan interpretations the proper
standard of review is de novo “unless the benefit plan gives the
administrator or fiduciary discretionary authority to deter-
mine eligibility for benefits or to construe the terms of the
plan.” Id. at 115. Phrasing this more generally, review is def-
erential over decisions that have been committed to the dis-
cretion of the plan administrator. See, e.g., Operating Eng'rs
Local 139 Health Benefit Fund v. Gustafson Constr. Corp., 258
F.3d 645, 653 (7th Cir. 2001) (arbitrary and capricious stand-
ard applied to trustees’ determination regarding interest and
Nos. 14-3726, 14-3737                                          9

penalties owed on delinquent contributions where the plan
provided the trustees the power to construe provisions of the
collective bargaining agreement). If the particular type of de-
cision has been delegated to the administrator, then deference
is owed both to the decision and to the plan interpretation that
led to it. At the threshold, however, the court must decide
which matters were entrusted to the administrator and which
were not. (This is something like what happens when parties
debate whether a particular matter lies within the scope of an
arbitration agreement: courts usually decide that question,
although it is possible for the parties to agree to submit it to
the arbitrator. See First Options of Chicago, Inc. v. Kaplan, 514
U.S. 938, 944 (1995).)
    In order to determine whether an issue has been assigned
to the administrator, it is necessary to consult the plan docu-
ments to see what the parties have said. This involves the fa-
miliar process of contract interpretation, for which de novo re-
view is proper. We also address questions of law inde-
pendently. See Trustees of Chicago Truck Drivers, Helpers &
Warehouse Workers Union Pension Fund v. Leaseway Transporta-
tion Corp., 76 F.3d 824, 829 (7th Cir. 1996). To the extent that
the CBA is pertinent, we note that the Supreme Court recently
has reminded us that “[w]e interpret collective-bargaining
agreements, including those establishing ERISA plans, ac-
cording to ordinary principles of contract law … .” M&G Pol-
ymers USA, LLC v. Tackett, 135 S. Ct. 926, 933 (2015).
   The Fund argues that the governing language appears in
Article V, section 2 of the Revised and Amended Trust Agree-
ment for Central States, Southeast and Southwest Areas Pen-
sion Fund (Trust Agreement), which reads as follows:
10                                         Nos. 14-3726, 14-3737

     All questions or controversies, of whatsoever charac-
     ter, arising in any manner or between any parties or
     persons in connection with the Fund or the operation
     thereof, whether as to any claim for any benefits pre-
     ferred by any participant, beneficiary, or any other per-
     son, or whether as to the construction of the language
     or meaning of the rules and regulations adopted by the
     Trustees or of this instrument, or as to any writing, de-
     cision, instrument or accounts in connection with the
     operation of the Trust Fund or otherwise, shall be sub-
     mitted to the Trustees, or to a committee of Trustees,
     and the decision of the Trustees or of such committee
     thereof shall be binding upon all parties or persons
     dealing with the Fund or claiming any benefit thereun-
     der. The Trustees are vested with discretionary and fi-
     nal authority in making all such decisions, including
     Trustee decisions upon claims for benefits by partici-
     pants and beneficiaries of the Pension Fund and other
     claimants, and including Trustee decision construing
     plan documents of the Pension Fund. To the extent this
     section is contrary to or inconsistent with a Named Fi-
     duciary Agreement, this section shall be inapplicable.
    The category “any writing, instrument or accounts in con-
nection with the operation of the Trust Fund” is very broad.
Nonetheless, there are good reasons to think that the CBA
does not qualify. The CBA itself does not describe or summa-
rize the terms of the plan. It is, however, a document that is
related to the plan. Even so, there is nothing in the Trust
Agreement that purports to confer on the Trustees the power
to interpret agreements between third parties—even agree-
ments to determine the date on which an employer and a un-
ion jointly agree to withdraw from the Fund. Moreover, no
Nos. 14-3726, 14-3737                                          11

employer is required by law to participate in any particular
fund, or indeed in any fund at all. See Central Laborers' Pension
Fund v. Heinz, 541 U.S. 739, 743 (2004) (noting with regard to
pensions that “[n]othing in ERISA requires employers to es-
tablish employee benefits plans” or “mandate[s] what kind of
benefits employers must provide if they choose to have such
a plan”). If we had to decide, we would thus be inclined to say
that the scope of the 2006 CBA and the proper legal character-
ization of the extension agreements are both decisions that lie
outside the scope of Article V, section 2.
     But in the end it does not matter how we characterize the
2006 CBA. Even under ERISA’s arbitrary and capricious
standard of review, a plan administrator’s “interpretation
may not controvert the plain language of the document.” Cot-
tillion v. United Ref. Co., 781 F.3d 47, 55 (3d Cir. 2015). As we
previously have noted, “[i]n some cases, the plain language
or structure of the plan or simple common sense will require
the court to pronounce an administrator's determination arbi-
trary and capricious.” Tompkins v. Central Laborers' Pension
Fund, 712 F.3d 995, 1002 (7th Cir. 2013) (quoting Hess v. Hart-
ford Life & Accident Ins. Co., 274 F.3d 456, 461 (7th Cir. 2001)).
This is one of those cases.
                                B
   Under ERISA, plan fiduciaries are obliged to assure the fi-
nancial integrity of a plan by, among other things, “holding
employers to the full and prompt fulfillment of their contri-
bution obligations.” See Central States, Southeast & Southwest
Areas Pension Fund v. Cent. Transp., Inc., 472 U.S. 559, 574
(1985). The Multiemployer Pension Plan Amendments Act of
1980 (MPPAA) “arose out of Congress’ fear that any time an
employer withdrew from a multiemployer pension plan
12                                       Nos. 14-3726, 14-3737

(MPP) under ERISA it could set off a domino effect that,
‘much like a bank run,’ could leave the MPP unable to pay its
vested obligations.” Central States, Southeast & Southwest Areas
Pension Fund v. Hunt Truck Lines, Inc., 204 F.3d 736, 739 (7th
Cir. 2000) (citation omitted). ERISA provides that an em-
ployer’s obligation to contribute to a plan arises either “under
one or more collective bargaining (or related) agreements, or
… as a result of a duty under applicable labor-management
relations law … .” 29 U.S.C. § 1392(a). The present case does
not rest on any independent legal duty; we can thus disregard
the second option under the statute.
    Section 515 of ERISA provides that an employer “who is
obligated to make contributions to a multiemployer plan un-
der the terms of the plan or under the terms of a collectively
bargained agreement shall, to the extent not inconsistent with
law, make such contributions in accordance with the terms
and conditions of such plan or such agreement.” 29 U.S.C. §
1145. The statute also dictates when the obligation to contrib-
ute ceases: “a complete withdrawal from a multiemployer
plan occurs when an employer—(1) permanently ceases to
have an obligation to contribute under the plan, or (2) perma-
nently ceases all covered operations under the plan.” 29
U.S.C. § 1383(a). The date of complete withdrawal is defined
as “the date of the cessation of the obligation to contribute or
the cessation of covered operations.” Id. § 1383(e).
    In our case, Michels’s obligation to contribute is tied ex-
clusively to the 2006 CBA. See Parmac, Inc. v. I.A.M. Nat’l Pen-
sion Fund Benefits Plan A, 872 F.2d 1069, 1072 (D.C. Cir. 1989);
see also Trustees of Local 138 Pension Trust Fund v. F.W.
Honerkamp Co., 692 F.3d 127, 135 (2d Cir. 2012). The Fund rec-
ognizes this, but it argues that the 2006 CBA did not expire
Nos. 14-3726, 14-3737                                         13

until the end of May 2012. Before that, it says, the parties ex-
tended the 2006 CBA numerous times, and therefore Michels
never acquired the right to withdraw. It concedes that the No-
vember 15, 2011, extension purported to eliminate the obliga-
tion to contribute to the Fund, but it says that this language
was inconsistent with Article III, section 7(a) of the Trust
Agreement, which provides that “[a]n employer is obliged to
contribute to the Fund for the entire term of any collective bar-
gaining agreement accepted by the Fund on the terms stated in
that collective bargaining agreement … .” (Emphasis added.)
This language, it concludes, makes the attempted repudiation
of the obligation to contribute ineffective.
    None of the cases upon which the Fund relies support its
position. In Central States, Southeast & Southwest Areas Pension
Fund v. Auffenberg Ford, Inc., 637 F.3d 718, 721 (7th Cir. 2011),
we considered the validity of an oral agreement governing an
employer’s duty to contribute to a fund. This, we found, was
insufficient to override the written requirement for contribu-
tions found in the governing CBA. See also 29 U.S.C.
§ 1102(a)(1). The decision in Central States, Southeast & South-
west Areas Pension Fund v. Waste Management of Michigan, Inc.,
674 F.3d 630 (7th Cir. 2012), is also inapposite. There we re-
jected an employer’s effort to terminate its contribution obli-
gations before the stated expiration date of a CBA. No ques-
tion about the effectiveness of post-expiration extension
agreements was before the court. Central States, Southeast &
Southwest Areas Pension Fund v. Fingerle Lumber Co., No. 08 C
1886, 2009 WL 1137793 (N.D. Ill. April 22, 2009), came to a
similar result. There the bargaining parties had initially
agreed to make contributions up to a particular date, and later
they agreed on an earlier time. The court held that they could
14                                      Nos. 14-3726, 14-3737

not advance their withdrawal date, because the Fund had re-
lied on the initial duration of the agreement.
    The present case differs from each of these. First, we are
not evaluating any oral agreements. Second, no one tried to
withdraw on a date earlier than the one specified in the 2006
CBA (January 31, 2011) or even earlier than the date in the
ninth extension agreement, November 15, 2011. To the con-
trary, Michels complied with its contribution obligations
through the November date. The Fund had no reason to think
that the parties would extend the 2006 CBA even a minute
beyond November 15, 2011. It learned the two critical points
here at the same moment: there would be another extension,
but the 2006 CBA was going to be modified to exclude a con-
tribution obligation.
    Michels argues that we should ignore the Trust Agree-
ment and look only to the 2006 CBA. The language of the stat-
ute provides some support for this position. Under 29 U.S.C.
§ 1381, a withdrawal is effective when the employer “perma-
nently ceases to have an obligation to contribute under the
plan.” The statute clarifies that “an obligation to contribute”
is an obligation “arising under one or more collective bargain-
ing agreements.” 29 U.S.C. § 1382(a)(1). By mentioning only
CBAs and no other document, the statute indicates that Mi-
chels’s obligation to contribute is tied to the 2006 CBA. See
Parmac, Inc., 872 F.2d at 1072 (“The law is clear that an em-
ployer’s withdrawal liability under the MPPAA must be de-
termined by looking at the employer’s collective bargaining
agreement.”).
   Even if we conclude that the 2006 CBA controls, our job is
not finished. That is because the parties disagree about what
Nos. 14-3726, 14-3737                                        15

document or documents qualify as the governing CBA. Mi-
chels argues that the November 15, 2011, extension agreement
is the CBA in question, because the 2006 CBA had long since
expired. We agree with this analysis. Article XV(C) of the 2006
CBA permitted either party to provide written notice no less
than 60 days before the expiration date of its intention to ter-
minate the agreement. PLCA gave such notice to the Union
by a letter sent August 9, 2010, well more than 60 days before
January 31, 2011. PLCA never revoked that notice, and so the
CBA was terminated in keeping with this procedure. At that
time, the parties entered a phase during which negotiations
were continuing, but no new agreement had been concluded.
True, they executed a series of brief extensions that had the
effect of carrying forward the terms of the 2006 CBA, but they
were under no obligation to do so. Each one of these letter
agreements stood on its own.
    As PLCA and Michels point out, in a somewhat different
context this is the way that the National Labor Relations
Board (the Board) has understood interim agreements—as
binding, stand-alone CBAs. When a union is interested in
challenging the role of an incumbent union as the certified
bargaining representative, it may file a rival election petition
and see how it fares at the workplace. But it cannot do so just
anytime. It must wait until the open period 60 to 90 days be-
fore the governing collective bargaining agreement expires
(or later) before doing so. Before that time, the existing con-
tract bars the rival union’s challenge—hence the name “con-
tract bar” to describe this policy. In Union Carbide Corp., 190
N.L.R.B. 191 (1971), the Board had to decide whether a peti-
tion for an election that had been filed on August 6, 1970,
could go forward or if it was impermissible under the contract
bar. As of that date, the Board wrote, the third anniversary of
16                                      Nos. 14-3726, 14-3737

the 1967 agreement had passed and a petition filed then
would have been entertained. But the parties executed a mod-
ification of the existing agreement on September 29, 1969,
with a new expiration date of October 15, 1972. The Board re-
garded the modification as a new contract; it rejected the ar-
gument that it was incorporated into and made a part of the
1967 agreement. Although the context is different, the Union
Carbide ruling supports the idea that the various extensions
were not merged into the 2006 CBA.
    The Fund pushes back with the assertion that its posi-
tion—that the November 15, 2011 agreement was not a new
CBA—squares better with the mechanics of collective bar-
gaining agreements. Labor law requires that for a new collec-
tive bargaining agreement to be created, it must be approved
by a vote of the membership of the union. See Booster Lodge
No. 405, Int'l Ass'n of Machinists & Aerospace Workers, AFL-CIO
v. NLRB, 412 U.S. 84, 86 (1973). The Teamsters Constitution is
no exception: it states that a new CBA is “ratified by majority
vote of the Local Unions having and exercising jurisdiction
over the work covered by the agreement,” and it is not bind-
ing until after that vote. The Union membership did not vote
on any of the one-month extensions to the 2006 CBA. They
voted on nothing until the new CBA was presented to them
in June 2012. This argument, however, proves too much. It is
common in labor relations for one collective bargaining agree-
ment to expire before a new full-blown agreement can be con-
cluded. The parties must, and do, continue to bargain during
that interim period, and they often agree to carry forward the
terms of the old CBA (perhaps with some modifications) if the
bargaining is still fruitful and impasse has not been reached.
                                C
Nos. 14-3726, 14-3737                                               17

   Even if we downplay the importance of the 2006 CBA, we
would come to the same result. The plain language of the
Trust Agreement also compels a decision in Michels’s favor.
The Trust Agreement recognizes two scenarios in which the
obligation to contribute may properly be terminated:
   The obligation to make such contributions shall con-
   tinue (and cannot be retroactively reduced or elimi-
   nated) after termination of the collective bargaining
   agreement until the date the Fund receives a) a signed con-
   tract that eliminates or reduces the duty to contribute to the
   Fund or b) written notification that the Employer has
   lawfully implemented a proposal to withdraw from
   the Fund or reduce its contributions at the above-spec-
   ified address.
Trust Agreement, Article III, section 1 (emphasis added). This
provision could not be clearer: the obligation to contribute
ends when the fund receives a signed contract that eliminates
or reduces the duty to contribute to the fund. That is exactly
what the Fund received from Michels on November 16, 2011.
Nothing the parties did was inconsistent with this provision.
There is nothing noteworthy about the fact that Michels and
the other PLCA parties contributed to the Fund during the
post-termination months; after all, they were obliged to do so
until the Fund received the signed contract eliminating this
obligation to which this language refers.
    The Fund evidently thinks that the “signed contract” men-
tioned in Article III, section 1 must be a new CBA, and that
the November 15, 2011, agreement was not a new CBA. But
the Trust Agreement does not require that the “signed con-
tract” mentioned in Article III, section 2, be a CBA. It would
have been easy enough to use that term, not the term “signed
18                                      Nos. 14-3726, 14-3737

contract.” As PLCA points out, the relevant section of the
Trust Agreement uses the term “collective bargaining agree-
ment” nine times, while subpart (a) uses the broader phrase
“signed contract.” The Fund received just such a “signed con-
tract” when the November 15, 2011 agreement, amending and
extending the CBA, was delivered to it.
   Elsewhere the Trust Agreement also recognizes that there
might be something other than a collective bargaining agree-
ment. Article III lists “each new or successive collective bar-
gaining agreement, including but not limited to interim
agreements and memoranda of understanding between the
parties” as among the items that must be sent to the Fund. The
term “interim agreement” describes the extensions (and the
November 11, 2015 amendment and extension) perfectly. The
conclusion that these were separate agreements thus fits with
the language of the 2006 CBA and with the language of the
Trust Agreement. In concluding that the November 15, 2011
agreement was insufficient to allow Michels to withdraw
from the Fund, the Fund contravened the plain language of
the Trust Agreement. Its decision was therefore arbitrary and
capricious.
    Looking to other agreements only further sinks the Fund’s
arguments. The National Participation Agreement, which ap-
pears as Schedule B of the 2006 CBA, governs the relationship
between individual employers and the Fund. After stating
that the employers agree to make contributions pursuant to
the CBA, the Participation Agreement adds the following pro-
viso: “no amendments or provisions of said trust agreements
shall bind the Employer for any financial obligations or dues
delinquency determinations beyond that set forth in the Na-
Nos. 14-3726, 14-3737                                      19

tional Pipe Line Agreement pursuant to which such contribu-
tions are made.” That language supports a duty to contribute
during the life of the 2006 CBA, and during the extensions up
until November 15, 2011. It does not support any such duty
thereafter, however, because the November 15 agreement sets
the financial obligation to the Central States Fund at zero,
while at the same time it provides for escrowing money to be
given to a successor fund. The Fund’s only response to this is
to attack the amendment as unauthorized, along the lines we
already have outlined. Its argument, however, depends en-
tirely on the idea that the 2006 CBA continued in full force
until some time beyond November 2011—perhaps all the way
until the new collective bargaining agreement was concluded.
We are persuaded, however, that this is incorrect, under the
agreements that linked these parties, as we discussed in Part
II.B of this opinion.
                             III
   We therefore conclude that the collective bargaining
agreement between PLCA and the Union expired in accord-
ance with its terms on January 31, 2011. Until November of
that year, it was followed by a series of separate agreements,
each of which carried the terms of the expired CBA forward.
In November, the parties exercised their right to change the
term before us now: the duty to contribute to the Fund. They
properly notified the Fund in writing of this prospective
change. The district court’s judgment in favor of the Fund
therefore must be, and is, REVERSED.
