dissenting:
I respectfully dissent from the majority opinion. I would affirm the bankruptcy court based on the following grounds.
A. Liquidity
The bankruptcy court held that the IRS’s claims were not liquidated because the IRS did not “provide evidence showing a reasonable basis for the assessment” of its claim. The majority holds that the IRS may rely on the presumptive validity of its proof of claim in order to meet its burden of proof for setoff. I disagree.
The burden of proving the right to setoff rests with the party asserting that right. In re County of Orange, 183 B.R. 609, 615 (Bankr.C.D.Cal.1995). In order to meet its burden of proof, a creditor must show that the debt was liquidated. Although the term liquidated is not defined in the Bankruptcy Code, the Ninth Circuit has stated that “the question of whether a debt is liquidated turns on whether it is subject to ‘ready determination and precision in computation of the amount due.’ ” In re Fostvedt, 823 F.2d 305, 306 (9th Cir.1987). A debt is not subject to “ready determination” if the court must conduct an extensive and contested evidentiary hearing in which substantial evidence is required to establish the amount of the debt or liability, as opposed to a simple hearing on the amount of the debt. In re Wenberg, 94 B.R. 631, 634 (9th Cir. BAP 1988), aff'd, 902 F.2d 768 (9th Cir.1990). The bankruptcy judge is in the best position to determine whether an extensive hearing is required. Id. at 635.
The majority holds that the IRS met its burden of proof through the prima facie validity of its proof of claim, or at least the court should have allowed the IRS an opportunity to show how it arrived at its figures. Courts which have addressed the issue of whether a tax debt was liquidated have required some showing of proof beyond the IRS’s proof of claim. In In re Ekeke, 198 B.R. 315, 318 (Bankr.E.D.Mo.1996), the court required that the IRS make a prima facie showing as to the amount of its claim regarding calculation of the debt through the debt- or’s tax returns. This showing was in addi*225tion to the IRS’s filed proof of claim. In In re Elrod, 178 B.R. 5, 6 (Bankr.N.D.Okla.1995), although the IRS had filed a proof of claim, the court held that the tax debt was unliquidated because the court could not determine the amount of the IRS’s claim without holding an evidentiary hearing.
The IRS’s proof of claim is irrelevant. More relevant is the rule that a tax assessment is presumptively correct. The bankruptcy court stated that the rationale to this rule is that if the assessment is incorrect, the taxpayer has access to the documents which could dispute the correctness of the assessment. However, the court stated that this same rationale is not applicable when the IRS seeks to use its right of setoff to defeat the rights of third parties. The third party will not have access to the documents required to dispute the validity of the assessment. In such a ease, the court held that the tax debt will not be considered liquidated unless the IRS can show a reasonable basis for the assessment, such as a filed tax return or otherwise. I agree.
The bankruptcy court did give the IRS an opportunity to provide a basis for its assessments. After the initial hearing on the IRS’s motion, the bankruptcy court was made aware of the fact that the debtors .had filed tax returns for pre-petition tax periods after the original proof of claim was filed. The court, in a telephonic conference, requested copies of these returns so that the court could review the amount of tax that the debtors claim they owed. The court held these taxes liquidated. If the IRS had other returns or other evidence which would substantiate the precise amount of the remaining tax debt, the IRS should have submitted its evidence, as it was the IRS who was responsible for meeting its burden of proof. The burden was not on the court to specifically request evidence of which the court was not aware, especially where much of the tax debt was for years in which no return was filed. The bankruptcy court held as liquidated the tax debt for years for which a filed return was submitted to the court. The court found that the IRS had not met its burden of proof on the balance of the tax debt and held the debt to be unliquidated.
The bankruptcy court was in the best position to determine the extent of the evidence needed to determine the precise amount of the debt. The court determined that the IRS would have to submit some evidence supporting the assessment because it was asserting its right to offset against a third party. The IRS did not submit the necessary evidence and the court was not required to specifically request each document that would support the assessments. The balance of the tax debt could not be precisely determined by simple mathematical computation and was not subject to ready determination as most of the debt was for years in which no return was filed. As such, the bankruptcy court properly held that the balance of the debt was not liquidated.
B. Maturity
The majority states that “[t]he court below correctly found that the IRS claim against the debtors were matured at the time of notification.” This is a mischaracterization of the bankruptcy court’s holding. The bankruptcy court held that the IRS held a matured claim only for liquidated taxes. Medina, 177 B.R. at 354. The court stated, “[t]he IRS held a matured claim against the debtors for the balance of the liquidated taxes. Therefore, as to those taxes for which setoff is otherwise available under nonbank-ruptcy law, the IRS has priority over Offord as assignee.” Id. The only claims which the court held to be liquidated and therefore available for setoff were for tax debt for years in which the debtor filed a return. Thus, the bankruptcy court held that only those tax debts for years in which a return was filed were liquidated and matured. This distinction is of importance as the majority opinion holds that the bankruptcy court abused its discretion in ruling certain IRS claims to be unliquidated. Claims for tax debt in which no return has been filed or no assessment made are not matured for purposes of setoff in these circumstances, where a third party intervenes and perfects its lien. The IRS’s tax lien arises only at the time that assessment is made pursuant to § 6321 of the Internal Revenue Code. Where the debtor has filed a return, which is a self-*226assessment, the claim is matured. I agree with the bankruptcy court that the IRS claims for years in which a return was filed were both liquidated and matured. However, to the extent that the majority opinion holds that all of the IRS claims were matured, I disagree.
C. Discretion of the bankruptcy court
The law is clear that the ultimate decision on the allowance of setoff rests within the discretion of the bankruptcy court. The majority opinion holds that the bankruptcy court abused its discretion because it did not cite any compelling circumstances for disallowing the setoff. In this case, there were sufficiently compelling circumstances to deny the setoff. The IRS received notification of the debtor’s assignment to Offord while it held an unliquidated, unrecorded tax debt— in essence a secret lien. See C. Richard McQueen and Jack F. Williams, Tax Aspects of Bankruptcy Law and Practice, § 8.07 at 8-9 (2d ed. 1995) (stating that until the IRS properly files a notice of lien, the IRS holds a secret lien). Offord was helpless to protect itself against the IRS’s claim to offset based upon a secret lien. An assignee has a duty to protect itself against potential setoff claims before taking an assignment by checking for recorded IRS liens or requesting copies of the assignor’s filed tax returns. If there are no recorded liens, as in this case, and if the debtor did not file any returns, the assignee is helpless to protect itself from an offset based on a secret lien. In the meantime, here the assignee extended new value necessary for the debtor to complete its reforestation contracts while unknowingly subjecting itself to the IRS’s claim for offset.
The majority states that if a potential as-signee requests copies of filed tax returns which are not produced, the assignee is put on notice that something is amiss, such as the possibility of unassessed taxes. This suggestion however, flies in the face of the wealth of recording hen perfection statutes that have long established a policy requiring that hens be recorded in a certain place, at which place a potential creditor or assignee would be able to search for recordation and become informed of a perfected hen. Under these statutes, a potential creditor or as-signee is only required to search for a recorded hen, so that it does not have to ask a debtor about the existence of hens and risk an incomplete or inaccurate response. The recording hen perfection statutes instead provide for a creditor’s sole method for protecting its hen — through recordation, which the IRS failed to do. If a court allows the IRS to setoff claims for taxes in which the debtor did not file a return and the IRS did not record a hen, then the assignment of the contract proceeds is defeated by the secret hen. Such a situation leaves the as-signee with no means of protecting itself from setoff claims of which it was unaware, and presents sufficiently compelling circumstance for disallowance of setoff.
Accordingly, I would affirm the decision of the bankruptcy court.