delivered the opinion of the Court.
In this original proceeding, the question is whether Kellogg Brown
&
Root, Inc. (“KBR”), as a non-signatory to a contract containing an arbitration clause, must arbitrate its claims against Unidynamics, Inc. (“Unidynamics”) and MacGREGOR (FIN) Oy (“MacGregor”) — the signatories to the contract. The trial court denied MacGre-gor’s motion, which sought to compel KBR to pursue its claims in an ongoing arbitration between MacGregor and Unidynam-ics. The court of appeals held that the trial court abused its discretion and conditionally granted mandamus relief, ordering the trial court to vacate its order denying MacGregor’s motion and “issue an order compelling KBR to arbitrate all claims.”
Approximately two months after KBR filed its petition here, the arbitration between MacGregor and Unidynamics concluded. As a result, the relief MacGregor requested in the lower courts — that KBR be compelled “to pursue its claims in the arbitration between MacGregor (FIN) and Unidynamics” — is no longer available. The case is not moot, however, because the parties continue to dispute whether KBR should be compelled to “arbitrate all claims” pursuant to the court of appeals’ order. Id. at 184. Because we conclude that KBR cannot be so compelled, we conditionally grant mandamus relief and order the court of appeals to vacate its order.
I
Factual Background
In October 1999, MacGREGOR (USA), Inc. contracted with Ingalls Shipbuilding, Inc. (“Ingalls”) to build elevator trunks for two cruise ships. MacGREGOR (USA) assigned the contract to its sister compa *735 ny, MacGREGOR (FIN) Oy 1 (“MacGre-gor”). In August 2000, MacGregor subcontracted part of the job to Unidynamics, which agreed to fabricate a set of the elevator trunks for one of the ships. 2 In June 2001, Unidynamics and KBR entered into a second-tier subcontract, under which KBR agreed to furnish labor, equipment, and facilities to fabricate the elevator trunks. In the fabrication subcontract between MacGregor and Unidynamics, the parties agreed that: “Any disputes arising from the interpretation or application of this contract including any document pertaining thereto, shall be settled by arbitration in accordance with General Conditions (ECE 188), (Appendix 10).” 3 The second-tier subcontract between Unidynamics and KBR did not contain an arbitration provision.
After the ship buyer declared bankruptcy in November 2001, Ingalls directed MacGregor to cease work and notify its subcontractors to do the same. MacGre-gor directed Unidynamics to comply with “the same instructions that Ingalls gave MacGregor.” Unidynamics conveyed those instructions to KBR. On or around November 5, 2001, KBR ceased work, stored the elevator trunks and other equipment, and sent Unidynamics invoices for unpaid fabrication services and storage costs. Because KBR had not been paid in full, it asserted liens on the elevator trunk fabrications, parts, and other materials (the “collateral”).
A dispute then arose between MacGre-gor and Unidynamics regarding who owned the collateral and who owed KBR for the fabrication services and storage costs. The dispute stemmed from MacGregor and Unidynamics’ Agreement Concerning Passing of Title (the “Title Agreement”), executed on December 5, 2001, and fully incorporated into their fabrication subcontract. Among other things, the Title Agreement provided that full title to the collateral would pass irrevocably to MacGregor immediately after MacGregor made two payments to Unidy-namics, which were to occur no later than December 19, 2001. The Title Agreement further required Unidynamics to release the collateral to MacGregor upon MacGre-gor’s request. It is undisputed that MacGregor timely paid Unidynamics; however, Unidynamics asserted that the payments were ineffective to pass title to MacGregor. When MacGregor demanded that Unidynamics release the elevator trunks, Unidynamics refused. The collateral remained in KBR’s possession.
II
Procedural Background
In May 2002, pursuant to the arbitration provision in the fabrication subcontract, MacGregor asked the International Chamber of Commerce (“ICC”) to arbitrate its dispute with Unidynamics. Among other things, MacGregor sought: (1) damages for breach of contract by Unidynamics for failure to release the collateral, (2) a deter- *736 ruination as to which defendant owned the collateral, and (3) a determination regarding MacGregor’s proportionate responsibility for the storage costs KBR billed Uni-dynamics. Unidynamics filed an answer and asserted counterclaims. MacGregor and Unidynamics then commenced arbitration in Paris, France.
While the arbitration was proceeding, both MacGregor and Unidynamics demanded that KBR release the collateral. KBR refused the demands and, on September 17, 2002, filed suit against both companies in Harris County. KBR claimed that Unidynamics breached its contract and, in the alternative, that it was entitled to recover quantum, meruit damages against Unidynamics and MacGregor. KBR also sued for declaratory relief to determine which defendant owned the collateral. Subject to the court’s ruling on ownership, KBR sought a judicial declaration that it possessed valid constitutional and statutory liens against the collateral in its possession. 4 MacGregor answered and sought a temporary restraining order, temporary injunction, and permanent injunction directing KBR to release the collateral. Unidynamics opposed MacGre-gor’s application, arguing that the court action should be abated because the collateral’s ownership was “the very issue ... being arbitrated before the ICC.” MacGre-gor, Unidynamics, and KBR then negotiated an agreement, which the trial court entered as an Agreed Order. Pursuant to that order, MacGregor agreed to post a $1,000,000 bond and, upon presentation of the bond, KBR agreed to release the collateral to MacGregor. 5 MacGregor posted the bond on October 28, 2002.
Meanwhile, on October 18, 2002, MacGregor filed a motion to abate the state court proceedings pending its arbitration with Unidynamics or, in the alternative, to compel KBR to pursue its claims in the ongoing arbitration between MacGregor and Unidynamics. The trial court denied MacGregor’s motion. On December 19, 2002, MacGregor filed an interlocutory appeal and a petition for writ of mandamus in the court of appeals, contending that the trial court abused its discretion. The court of appeals dismissed the interlocutory appeal as moot and conditionally granted mandamus relief, ordering the trial court “to vacate its order denying MacGregor’s plea in abatement and motion to compel arbitration, to issue an order compelling KBR to arbitrate all claims, and to stay all proceedings pending arbitration.”
6
On December 9, 2003, KBR petitioned this Court for a writ of mandamus. On February 4, 2004, while the petition was pending before us, the arbitration between MacGregor and Unidynamics concluded, and the ICC issued a final arbitration award. KBR does not contest that award.
HI
Mootness
As a preliminary matter, we must decide whether the ICC’s final arbi
*737
tration award moots this mandamus proceeding. A case becomes moot if a controversy ceases to exist between the parties at any stage of the legal proceedings, including the appeal.
Allstate Ins. Co. v. Hallman,
A case is not rendered moot simply because some of the issues become moot during the appellate process.
See Allstate,
The live controversy in this proceeding is whether KBR must arbitrate those claims that remain now that the arbitration between MacGregor and Unidynam-ics has concluded. KBR’s petition consisted of: (1) a breach-of-contract claim against Unidynamics; (2) in the alternative, a quantum meruit claim against Un-idynamics and MacGregor; and (3) a declaratory judgment action to determine the collateral’s owner and to establish that KBR possessed valid hens. The arbitrator determined that, pursuant to the Title Agreement between MacGregor and Unidynamics, title to the collateral passed from Unidynamics to MacGregor on December 10, 2001. KBR is satisfied with this resolution of the ownership dispute, and thus, we need not address whether the ownership dispute must be arbitrated. Additionally, we need not address whether KBR should be compelled to arbitrate its claims against Unidynamics, because the parties now agree that those claims are not subject to arbitration. Our inquiry is accordingly limited to determining whether KBR must arbitrate its quantum meruit and lien-validity claims against MacGregor.
IV
Discussion
The parties do not dispute the court of appeals’ holding that the arbitration provision at issue is governed by the Federal Arbitration Act (“FAA”).
See
9 U.S.C. §§ 1-16;
Under the FAA, ordinary principles of state contract law determine whether there is a valid agreement to arbitrate.
First Options of Chi., Inc. v. Kaplan,
Although state law determines the validity of an arbitration agreement, courts have applied both federal and state law to determine the related, but distinct, issue of whether non-signatory plaintiffs should be compelled to arbitrate their claims.
See, e.g., Bailey,
Federal courts of appeals, however, have frequently applied federal substantive law when deciding whether a non-signatory must arbitrate.
See, e.g., Bailey,
Federal courts have recognized six theories, arising out of common principles of contract and agency law, that may bind non-signatories to arbitration agreements: (1) incorporation by reference; (2) assumption; (3) agency; (4) alter ego; (5) equitable estoppel, and (6) third-party beneficiary.
See, e.g., Bridas,
Under “direct benefits estop-pel,” a non-signatory plaintiff seeking the benefits of a contract is estopped from simultaneously attempting to avoid the contract’s burdens, such as the obligation to arbitrate disputes.
R.J. Griffin & Co.
at 160-61;
Bailey,
Consistent with the federal doctrine of “direct benefits estoppel,” this Court has held that a non-signatory plaintiff may be compelled to arbitrate if its claims are “based on a contract” containing an agreement to arbitrate.
In re FirstMerit Bank,
The issue here is whether KBR sought to enforce terms of the fabrication subcontract by (1) bringing a quantum meruit claim against MacGregor, or (2) seeking a declaration that it possessed valid liens. We begin with quantum meruit.
Quantum meruit
is an equitable remedy that “ ‘is based upon the promise implied by law to pay for beneficial services rendered and knowingly accepted.’ ”
Vortt Exploration Co., Inc. v. Chevron U.S.A., Inc.,
To advance its estoppel theory, MacGregor contends that KBR’s quantum meruit claim is “based on” the fabrication subcontract in the sense that KBR’s labor and services were linked inextricably to that subcontract. It is true, of course, that KBR was fabricating trunks that were at the contract’s core and that, in performing the work, KBR relied on the fabrication subcontract’s specifications. However, under “direct benefits estoppel,” a non-signatory plaintiff cannot be compelled to arbitrate on the sole ground that, but for the contract containing the arbitration provision, it would have no basis to sue. The work to be performed under a second-tier subcontract will inherently be related to and, to a certain extent, defined by contracts higher in the chain. See Black’s Law Dictionary 1464 (8th ed.2004) (defining subcontractor as “[o]ne who is awarded a portion of an existing contract by a contractor, esp. a general contractor”). If this were a sufficient basis for binding a non-signatory subcontractor, arbitration agreements would become easier to enforce than other contracts, counter to the FAA’s purpose. See InterGen, 344 F.3d at *741 145-46 (noting that federal courts have “been hesitant to estop a nonsignatory seeking to avoid arbitration”).
We conclude that, under “direct benefits estoppel,” although a non-signatory’s claim may relate to a contract containing an arbitration provision, that relationship does not, in itself, bind the non-signatory to the arbitration provision. Instead, a non-signatory should be compelled to arbitrate a claim only if it seeks, through the claim, to derive a direct benefit from the contract containing the arbitration provision.
See Bailey,
In its quantum meruit claim against MacGregor, KBR seeks payment for services rendered. KBR provided services pursuant to its contract with Unidy-namics. KBR’s asserted right to payment therefore stems directly from the KBR-Unidynamics contract, not the fabrication subcontract. The fabrication subcontract includes no provision for paying KBR. In fact, KBR is effectively precluded from asserting rights under that contract, which expressly provides that “Approved use of any subcontractor creates no contractual relationship between the subcontractor and [MacGregor].” 10 Thus, we conclude that the court of appeals abused its discretion to the extent it compelled KBR to arbitrate its quantum meruit claim against MacGregor.
Having determined that KBR’s
quantum meruit
claim is not subject to arbitration, we turn to KBR’s lien-validity claims. KBR sought a judicial declaration that it possessed valid constitutional and warehouseman’s statutory liens.
See
Tex. Const, art. XVI, § 37; Tex. Bus. & Com. Code § 7.209(a)(1). The self-executing constitutional lien attaches to buildings and special-order articles that are made or repaired by mechanics, material men, and artisans who have a direct contractual relationship with the owner of the property.
See
Tex. Const. art. XVI, § 37;
CVN Group, Inc. v. Delgado,
In this Court, MacGregor’s sole argument for compelling arbitration of KBR’s lien-validity claims is that the claims require a determination of ownership, and thus, they are “based on” the Title Agreement within the fabrication subcontract. 11 Ownership was, of course, a central issue before and during the Paris arbitration. When the arbitration award resolved the ownership dispute, it also eliminated the only rationale that MacGregor has asserted thus far for arbitrating the liens’ validity-
We do not decide whether other arguments may exist to compel KBR to arbitrate the validity of its liens. To the extent a lien dispute still remains, the trial court is in the best position to determine, on principles we have declared today, whether it must be arbitrated.
y
Conclusion
We conditionally grant mandamus relief and order the court of appeals to vacate its order compelling KBR to “arbitrate all claims.”
See
Notes
. The term "Oy” for Finnish companies is an abbreviation of "osakeyhtió” ("osake” means "share,” "yhtio” means "society”). See http://encyclopedia. laborlawtalk.com/Oy (last visited May 18, 2005, and available in Clerk of Court’s file).
. In October 2000, MacGregor and Unidy-namics entered into another subcontract, under which Unidynamics agreed to preassem-ble and install the elevator trunks. That subcontract is not at issue in this case.
.The arbitration provision in ECE 188 provided: "Any dispute arising out of the Contract shall be finally settled, in accordance with the Rules of Conciliation and Arbitration of the International Chamber of Commerce ["ICC”], by one or more arbitrators designated in conformity with those Rules."
. See Tex. Const, art. XVI, § 37; Tex. Bus. & Com.Code § 7.209.
. The parties agreed that the bond would be enforceable and payable in Texas, and that it would "constitute an unconditional promise to pay upon demand accompanied by proof of Final Judgment adjudicating the validity and amount, if any, of [KBR's] lien or liens against ... the collateral.”
.As of the date of this opinion, the trial court has not acted on the court of appeals’ orders. Proceedings have not resumed in the trial court since the court of appeals ordered a stay on January 9, 2003.
See
. Most federal courts, however, list only five of these theories, omitting third-party beneficiary as a separate ground.
See Local Union No. 38, Sheet Metal Workers’ Int’l Ass’n v. Custom Air Sys., Inc.,
. While not all federal courts use the phrase "direct benefits estoppel,” we adopt that terminology from
Bridas
to describe this form of estoppel. See
. Federal courts have also applied “direct benefits estoppel” to bind "non-signatories who, during the life of the contract, have embraced the contract despite their non-signatory status but then, during litigation, attempt to repudiate the arbitration clause in the agreement.”
E.I. DuPont de Nemours & Co.,
.
See MCI Telecomms. Corp. v. Tex. Utils. Elec. Co.,
. KBR's petition included the following:
29. Ownership. Given the Defendants' competing claims known to Plaintiff by the Defendants, Plaintiff seeks a declaration from the Court as to which Defendant(s) possesses the ownership rights, title and interest in the elevator shaft fabrications, component parts and other materials....
30. Constitutional Lien. Subject to the determination of ownership, Plaintiff also seeks a judicial declaration that Plaintiff possesses a valid constitutional lien to the elevator shaft fabrications, component parts and other materials pursuant to Article 16, § 37 of the Texas Constitution.
31. Statutory Lien. Subject to the determination of ownership, Plaintiff also seeks a judicial declaration that Plaintiff possesses a valid statutory lien to the elevator shaft fabrications, component parts and other materials pursuant to § 7.209 of the Texas Business and Commerce Code.
(Emphasis added.)
