delivered the opinion of the Court.
The question raised here is who bears the burden of proof on a tax claim in bankruptcy court when the substantive law creating the tax obligation puts the burden on the taxpayer (in this ease, the trustee in bankruptcy). We hold that bankruptcy does not alter the burden imposed by the substantive law.
I
The issue of state tax liability in question had its genesis in the purchase of an airplane by Chandler Enterprises, Inc., a now-defunct Illinois company. William J. Stoeeker, for whom petitioner Raleigh is the trustee in bankruptcy, was president of Chandler in 1988, when Chandler entered into a lease-purchase agreement for the plane, moved it to Illinois,
*18
and ultimately took title under the agreement. See
In re Stoecker,
According to respondent State Department of Revenue, the transaction was subject to the Illinois use tax, a sales-tax substitute imposed on Illinois residents such as Chandler who buy out of State. If the seller does not remit the tax, the buyer must, and, when buying a plane, must file a return and pay the tax within 30 days after the aircraft enters the State. Ill. Comp. Stat., ch. 35, §105/10 (1999). Chandler failed to do this.
When the State discovers a failure to file and pay taxes, its Department of Revenue (the respondent here) determines the amount of tax due and issues a Notice of Tax Liability to the taxpayer. §§ 105/12,120/4. Unless the taxpayer protests within the time provided, the assessment becomes final, though still subject to judicial review in the Illinois circuit court. §§120/4, 12.
Illinois law also provides that any corporate officer “who has the control, supervision or responsibility of filing returns and making payment of the amount of any ... tax ... who wilfully fails to file the return or make the payment . . . shall be personally liable for a penalty equal to the total amount of tax unpaid by the [corporation].” § 735/3-7. The department determines the amount, and its determination is “prima facie evidence of a penalty due,” ibid., though a Notice of Penalty Liability issued under this provision is open to challenge much like the antecedent Notice of Tax Liability.
By the time the department discovered the unpaid tax in this case, Chandler was defunct and Stoecker was in bankruptcy. The department issued both a Notice of Tax Liability against Chandler and a Notice of Penalty Liability against Stoecker. See
The record evidence about Chandler’s operations is minimal. A person named Pluhar acted as its financial officer.
*19
There is no evidence directly addressing Stoeeker’s role in the filing of Chandler’s tax returns or the payment of any taxes, and so no affirmative proof that he either was responsible for or willfully evaded the payment of the use tax, see
id.,
at 550. This evidentiary dearth is not necessarily dispositive, however, due to the provision of Illinois law shifting the burden of proof, on both production and persuasion, to the responsible officer once a Notice of Penalty Liability is issued, see
Branson
v.
Department of Revenue,
The Court of Appeals thought the trustee may have satisfied his burden of production by identifying Pluhar as the financial officer but, in any event, had not satisfied his burden of persuasion. Because Stoecker was the president and, as far as the record showed, he and Pluhar were the only officers, each would have been involved in Chandler’s tax affairs.
Ibid.
While it is true that failure to pay must be willful (at least grossly negligent) to justify the penalty under Illinois law, see
Branson, supra,
at 254-255,
Obviously, the burden of proof was critical to the resolution of the case, which the Department of Revenue won because the Court of Appeals held that the burden remained on the trustee, just as it would have been on the taxpayer had the proceedings taken place outside of bankruptcy. The Courts of Appeals are divided on this point: the Seventh Circuit joined the Third and Fourth Circuits in leaving the burden on the taxpayer. See
Resyn Corp.
v.
United States,
*20
II
Creditors’ entitlements in bankruptcy arise in the first instance from the underlying substantive law creating the debtor’s obligation, subject to any qualifying or contrary provisions of the Bankruptcy Code. See
Butner
v.
United States,
The scope of the obligation is the issue here. Do the State’s right and the taxpayer’s obligation include the burden of proof? Our eases point to an affirmative answer. Given its importance to the outcome of eases, we have long held the burden of proof to be a “substantive” aspect of a
*21
claim. See,
e. g., Director, Office of
Workers’
Compensation Programs
v.
Greenwich Collieries,
Tax law is no candidate for exception from this general rule, for the very faet that the burden of proof has often been placed on the taxpayer indicates how critical the burden rule is, and reflects several compelling rationales: the vital interest of the government in acquiring its lifeblood, revenue, see
Arkansas
v.
Farm Credit Servs. of Central Ark.,
Congress of course may do what it likes with entitlements in bankruptcy, but there is no sign that Congress meant to alter the burdens of production and persuasion on tax claims. The Code in several places, to be sure, establishes particular burdens of proof. See, e. g., 11 U. S. C. § 362(g) (relief from automatic stay), § 363(o) (adequate protection for creditors), *22 § 364(d)(2) (same), § 547(g) (avoidability of preferential transfer), § 1129(d) (confirmation of plan for purpose of avoiding taxes). But the Code makes no provision for altering the burden on a tax claim, and its silence says that no change was intended. 2
Ill
The trustee looks for an advantage in the very silence of the Code, however, first by arguing that actual, historical practice favored trustees under the Bankruptcy Act of 1898 and various pre-Code revisions up to the current Code’s enactment in 1978. He says that courts operating in the days of the Bankruptcy Act, which was silent on the burden to prove the validity of claims, almost uniformly placed the burden on those seeking a share of the bankruptcy estate. Because the Code generally incorporates pre-Code practice in the absence of explicit revision, the argument goes, and because the Code is silent here, we should follow the pre-Code practice even when this would reverse the burden imposed outside bankruptcy. This tradition makes sense, petitioner urges, because in bankruptcy tax authorities are no longer opposed to the original taxpayer, and the choice is no longer merely whether the tax claim is paid but whether other innocent creditors must share the bankruptcy estate with the taxing government.
We, however, find history less availing to the trustee than he says. While some pre-Code cases put the burden of proof
*23
on taxing authorities,
3
others put it on the trustee,
4
and still others eannot he fathomed.
5
This state of things is the end of the argument, for without the weight of solid authority on the trustee’s side, we cannot treat the Code as predicated on an alteration of the substantive law of obligations once a taxpayer enters bankruptcy. Cf.
United Sav. Assn. of Tex.
v.
Timbers of Inwood Forest Associates, Ltd.,
The trustee makes a different appeal to Code silence in pointing to language in
Vanston Bondholders Protective Comm.
v.
Green,
Finally, the trustee argues that the Code-mandated priority enjoyed by taxing authorities over other creditors, see 11 U. S. C. §§ 507(a), 503(b)(1)(B), requires a compensating equality of treatment when it comes to demonstrating validity of claims. But we think his argument distorts the legitimate powers of a bankruptcy court and begs the question about the relevant principle of equality.
Bankruptcy courts do indeed have some equitable powers to adjust rights between creditors. See,
e. g.,
§ 510(c) (equitable subordination). That is, within the limits of the Code, courts may reorder distributions from the bankruptcy estate, in whole or in part, for the sake of treating legitimate claimants to the estate equitably. But the scope of a bankruptcy court’s equitable power must be understood in the light of the principle of bankruptcy law discussed already, that the validity of a claim is generally a function of underlying substantive law. Bankruptcy courts are not authorized in the name of equity to make wholesale substitution
*25
of underlying law controlling the validity of creditors’ entitlements, but are limited to what the Bankruptcy Code itself provides. See
United States
v.
Reorganized CF&I Fabricators of Utah, Inc.,
Moreover, even on the assumption that a bankruptcy court were to have a free hand, the ease for a rule placing the burden of proof uniformly on all bankruptcy creditors is not self-evidently justified by the trustee’s invocation of equality. Certainly the trustee has not shown that equal treatment of all bankruptcy creditors in proving debts is more compelling than equal treatment of comparable creditors in and out of bankruptcy. The latter sort of equality can be provided by a bankruptcy court as a matter of course, whereas the trustee’s notion of equality could not be uniformly observed consistently with other bankruptcy principles. Consider the ease when tax litigation is pending at the time the taxpayer files for bankruptcy. The tax litigation will be subject to an automatic stay, but the stay can be lifted by the bankruptcy court for cause, see 11 U. S. C. § 362(d)(1), which could well include, among other things, a lack of good faith in attempting to avoid tax proceedings, or in attempting to favor private creditors who might escape the disadvantage of a priority tax claim under the trustee’s proposed rule. See generally 3 Collier on Bankruptcy ¶ 362.07[6][a], pp. 362-101 to 362-102 (rev. 15th ed. 2000) (noting that bad faith commencement of ease justifies lifting stay);
Internal Revenue Service
v.
Bacha,
The judgment of the Court of Appeals is affirmed.
It is so ordered.
Notes
It is true that a trustee may have less access to the facts than a taxpayer with personal knowledge, but the trustee takes custody of the taxpayer’s records, see 11 U.S. C. §521(4), and may have greater access to the taxpayer than a creditor. Even if the trustee’s advantage is somewhat less than the original taxpayer’s, the difference hardly overcomes the compelling justifications for shifting the burden of proof! The government, of course, is in no better position than it ever was, and remains without access to sources of proof when the taxpayer has not kept sufficient documentation.
The legislative history indicates that the burden of proof on the issue of establishing claims was left to the Rules of Bankruptcy Procedure. See S. Rep. No. 95-989, p. 62 (1978); H. R. Rep. No. 95-595, p. 352 (1977). The Bankruptcy Rules are silent on the burden of proof for claims; while Federal Rule of Bankruptcy Procedure 3001(f) provides that a proof of claim (the name for the proper form for filing a claim against a debtor) is “prima facie evidence of the validity and amount of the claim,” this rule does not address the burden of proof when a trustee disputes a claim. The Rules thus provide no additional guidance.
See,
e. g., United, States
v.
Sampsell,
See,
e. g., In re Uneco, Inc.,
See,
e. g., Fiori
v.
Rothensies,
