[align=left]
The SIP is an ERISA “ ‘employee pension benefit plan,’ ” 497 F. 3d 426, 427 (CA5 2007); 29 U. S. C. §1002(2), and the parties do not dispute that the plan satisfies ERISA’s antialienation provision, §1056(d)(1), which requires it to “provide that benefits provided under the plan may not be assigned or alienated.”11 The plan does, however, permit a beneficiary to submit a “qualified disclaimer” of benefits as defined under the Tax Code, see 26 U. S. C. §2518, which has the effect of switching the beneficiary to an “alternate … determined according to a valid beneficiary designation made by the deceased.” Supp. Record 86–87 (Exh. 15).
In 1971, William married Liv Kennedy, and, in 1974, he signed a form designating her to take benefits under the SIP, but naming no contingent beneficiary to take if she disclaimed her interest. 497 F. 3d, at 427.William and Liv divorced in 1994, subject to a decree that Liv “is … divested of all right, title, interest, and claim in and to … [a]ny and all sums … the proceeds [from], and any other rights related to any … retirement plan, pension plan, or like benefit program existing by reason of [William’s] past or present or future employment.” App. to Pet. for Cert. 64–65. William did not, however, execute any documents removing Liv as the SIP beneficiary, 497 F. 3d, at 428, even though he did execute a new beneficiary-designation form naming his daughter, Kari Kennedy, as the beneficiary under DuPont’s Pension and Retirement Plan, also governed by ERISA.
On William’s death in 2001, petitioner Kari Kennedy was named executrix and asked DuPont to distribute the SIP funds to William’s Estate. Ibid. DuPont, instead, relied on William’s designation form and paid the balance of some $400,000 to Liv. Ibid. The Estate then sued respondents DuPont and the SIP plan administrator (together, DuPont), claiming that the divorce decree amounted to a waiver of the SIP benefits on Liv’s part, and that DuPont had violated ERISA by paying the benefits to William’s designee.2
So far as it matters here, the District Court entered summary judgment for the Estate, to which it ordered DuPont to pay the value of the SIP benefits. The court relied on Fifth Circuit precedent establishing that a beneficiary can waive his rights to the proceeds of an ERISA plan “ ‘provided that the waiver is explicit, voluntary, and made in good faith.’ ” App. to Pet. for Cert. 38 (quoting Manning v. Hayes, 212 F. 3d 866, 874 (CA5 2000)).
The Fifth Circuit nonetheless reversed, distinguishing prior decisions enforcing federal common law waivers of ERISA benefits because they involved life-insurance policies, which are considered “ ‘welfare plan[s]’ ” under ERISA and consequently free of the antialienation provision. 497 F. 3d, at 429. The Court of Appeals held that Liv’s waiver constituted an assignment or alienation of her interest in the SIP benefits to the Estate, and so could not be honored. Id., at 430. The court relied heavily on the ERISA provision for bypassing the antialienation provision when a marriage breaks up: under 29 U. S. C. §1056(d)(3),3a court order that satisfies certain statutory requirements is known as a qualified domestic relations order, which is exempt from the bar on assignment or alienation. Because the Kennedys’ divorce decree was not a QDRO, the Fifth Circuit reasoned that it could not give effect to Liv’s waiver incorporated in it, given that “ERISA provides a specific mechanism—the QDRO—for addressing the elimination of a spouse’s interest in plan benefits, but that mechanism is not invoked.” 497 F. 3d, at 431.
We granted certiorari to resolve a split among the Courts of Appeals and State Supreme Courts over a divorced spouse’s ability to waive pension plan benefits through a divorce decree not amounting to a QDRO.4 552 U. S. ___ (2008). We subsequently realized that this case implicates the further split over whether a beneficiary’s federal common law waiver of plan benefits is effective where that waiver is inconsistent with plan documents, 5and after oral argument we invited supplemental briefing on that latter issue, upon which the disposition of this case ultimately turns. We now affirm, albeit on reasoning different from the Fifth Circuit’s rationale.
II
A
By its terms, the antialienation provision, §1056(d)(1), requires a plan to provide expressly that benefits be neither “assigned” nor “alienated,” the operative verbs having histories of legal meaning: to “assign” is “[t]o transfer; as to assign property, or some interest therein,” Black’s Law Dictionary 152 (4th rev. ed. 1968), and to “alienate” is “[t]o convey; to transfer the title to property,” id., at 96. We think it fair to say that Liv did not assign or alienate anything to William or to the Estate later standing in his shoes.
The Fifth Circuit saw the waiver as an assignment or alienation to the Estate, thinking that Liv’s waiver transferred the SIP benefits to whoever would be next in line; without a designated contingent beneficiary, the Estate would take them. The court found support in the applicable Treasury Department regulation that defines “assignment” and “alienation” to include
“[a]ny direct or indirect arrangement (whether revocable or irrevocable) whereby a party acquires from a participant or beneficiary a right or interest enforceable against the plan in, or to, all or any part of a plan benefit payment which is, or may become, payable to the participant or beneficiary.” 26 CFR §1.401(a)–13(c)(1)(ii) (2008).
See Boggs v. Boggs, 520 U. S. 833, 851–852 (1997) (relying upon the regulation to interpret the meaning of “assignment” and “alienation” in §1056(d)(1)). The Circuit treated Liv’s waiver as an “ ‘indirect arrangement’ ” whereby the Estate gained an “ ‘interest enforceable against the plan.’ ” 497 F. 3d, at 430.
Casting the alienation net this far, though, raises questions that leave one in doubt. Although it is possible to speak of the waiver as an “arrangement” having the indirect effect of a transfer to the next possible beneficiary, it would be odd usage to speak of an estate as the transferee of its own decedent’s property, just as it would be to speak of the decedent in his lifetime as his own transferee. And treating the estate or even the ultimate estate beneficiary as the assignee or transferee would be strange under the terms of the regulation: it would be hard to say the estate or future beneficiary “acquires” a right or interest when at the time of the waiver there was no estate and the beneficiary of a future estate might be anyone’s guess. If there were a contingent beneficiary (or the participant made a subsequent designation) the estate would get no interest; as for an estate beneficiary, the identity could ultimately turn on the law of intestacy applied to facts as yet unknown, or on the contents of the participant’s subsequent will, or simply on the participant’s future exercise of (or failure to invoke) the power to designate a new beneficiary directly under the terms of the plan. Thus, if such a waiver created an “arrangement” assigning or transferring anything under the statute, the assignor would be blindfolded, operating, at best, on the fringe of what “assignment” or “alienation” normally suggests.
The questionability of this broad reading is confirmed by exceptions to it that are apparent right off the bat. Take the case of a surviving spouse’s interest in pension benefits, for example. Depending on the circumstances, a surviving spouse has a right to a survivor’s annuity or to a lump-sum payment on the death of the participant, unless the spouse has waived the right and the participant has eliminated the survivor annuity benefit or designated a different beneficiary. See Boggs, supra, at 843; 29 U. S. C. §§1055(a), (b)(1)(C), (c)(2). This waiver by a spouse is plainly not barred by the antialienation provision. Likewise, DuPont concedes that a qualified disclaimer under the Tax Code, which allows a party to refuse an interest in property and thereby eliminate federal tax, would not violate the antialienation provision. See Brief for Respondents 21–23; 26 U. S. C. §2518. In each example, though, we fail to see how these waivers would be permis-sible under the Fifth Circuit’s reading of the statute and regulation.
Our doubts, and the exceptions that call the Fifth Circuit’s reading into question, point us toward authority we have drawn on before, the law of trusts that “serves as ERISA’s backdrop.” Beck v. PACE Int’l Union, 551 U. S. 96, 101 (2007) . We explained before that §1056(d)(1) is much like a spendthrift trust provision barring assignment or alienation of a benefit, see Boggs, supra, at 852, and the cognate trust law is highly suggestive here. Although the beneficiary of a spendthrift trust traditionally lacked the means to transfer his beneficial interest to anyone else, he did have the power to disclaim prior to accepting it, so long as the disclaimer made no attempt to direct the interest to a beneficiary in his stead. See 2 Restatement (Third) of Trusts §58(1), Comment c, p. 359 (2001) (“A designated beneficiary of a spendthrift trust is not required to accept or retain an interest prescribed by the terms of the trust… . On the other hand, a purported disclaimer by which the beneficiary attempts to direct who is to receive the interest is a precluded transfer”); E. Griswold, Spendthrift Trusts §524, p. 603 (2d ed. 1947) (“The American cases, though not entirely clear, generally take the view that the interest under a spendthrift trust may be disclaimed”); Roseberry v. Moncure, 245 Va. 436, 439, 429 S. E. 2d 4, 6 (1993) (“ ‘If a trust is created without notice to the beneficiary or the beneficiary has not accepted the beneficial interest under the trust, he can disclaim’ ” (quoting 1 A. Scott & W. Fratcher, Law of Trusts §36.1, p. 389 (4th ed. 1987) (hereinafter Fratcher))).
We do not mean that the whole law of spendthrift trusts and disclaimers turns up in §1056(d)(1), but the general principle that a designated spendthrift can disclaim his trust interest magnifies the improbability that a statute written with an eye on the old law would effectively force a beneficiary to take an interest willy-nilly. Common sense and common law both say that “[t]he law certainly is not so absurd as to force a man to take an estate against his will.” Townson v. Tickell, 3 Barn. & Ald. 31, 36, 106 Eng. Rep. 575, 576–577 (K. B. 1819).6
The Treasury is certainly comfortable with the state of the old law, for the way it reads its own regulation “no party ‘acquires from’ a beneficiary a ‘right or interest enforceable against the plan’ pursuant to a beneficiary’s waiver of rights where the beneficiary does not attempt to direct her interest in pension benefits to another person.” Brief for United States as Amicus Curiae 18. And, being neither “plainly erroneous [n]or inconsistent with the regulation,” the Treasury Department’s interpretation of its regulation is controlling. Auer v. Robbins, 519 U. S. 452, 461 (1997) .7
The Fifth Circuit found “significant support” for its contrary holding in the QDRO subsections, reasoning that “[i]n the marital-dissolution context, the QDRO provisions supply the sole exception to the anti-alienation provision,” 497 F. 3d, at 430, a point that echoes in DuPont’s argument here. But the negative implication of the QDRO language is not that simple. If a QDRO provided a way for a former spouse like Liv merely to waive benefits, this would be powerful evidence that the antialienation provision was meant to deny any effect to a waiver within a divorce decree but not a QDRO, else there would have been no need for the QDRO exception. But this is not so, and DuPont’s argument rests on a false premise. In fact, a beneficiary seeking only to relinquish her right to benefits cannot do this by a QDRO, for a QDRO by definition requires that it be the “creat[ion] or recogni[tion of] the existence of an alternate payee’s right to, or assign[ment] to an alternate payee [of] the right to, receive all or a portion of the benefits payable with respect to a participant under a plan.” 29 U. S. C. §1056(d)(3)(B)(i)(I). There is no QDRO for a simple waiver; there must be some succeeding designation of an alternate payee.8 Not being a mechanism for simply renouncing a claim to benefits, then, the QDRO provisions shed no light on whether a beneficiary may waive by a non-QDRO.
In sum, Liv did not attempt to direct her interest in the SIP benefits to the Estate or any other potential beneficiary, and accordingly we think that the better view is that her waiver did not constitute an assignment or alienation rendered void under the terms of §1056(d)(1).
B
DuPont has three other reasons for saying that Liv’s waiver was barred by ERISA. They are unavailing.
First, it argues that even if the waiver is not an assignment or alienation barred under the terms of §1056(d)(1), §1056(d)(3)(A) still prohibits it, in providing that §1056(d)(1) “shall apply to the creation, assignment, or recognition of a right to any benefit payable with respect to a participant pursuant to a domestic relations order [that is not a QDRO].” At the very least, DuPont reasons, Liv’s waiver included a “recognition” of William’s rights with respect to the SIP benefits. But DuPont overlooks the point that when subsection (d)(3)(A) provides that the bar to assignments or alienations extends to non-QDRO domestic relations orders, it does nothing to expand the scope of prohibited assignment and alienation under subsection (d)(1). Whether Liv’s action is seen as awaiver or as a domestic relations order that incorpor-ated a waiver, subsection (d)(1) does not cover it and §1056(d)(3)(A) does not independently bar it. Second, DuPont relies upon §1056(d)(3)(H)(iii)(II), providing that if a domestic relations order is not a QDRO, “the plan administrator shall pay the segregated amounts (including any interest thereon) to the person or persons who would have been entitled to such amounts if there had been no order.” According to DuPont, because the divorce decree was not a QDRO this provision calls for paying benefits as if there had been no order. But DuPont has wrenched this language out of its setting, reading clause (iii) of subparagraph (H) as if there were no clause (i):
[/align]