The parties disagree about whether the 1980 version or the 2007 version of the inheritance tax refund statute applies. The Department maintains that the probate court should have applied the 2007 version of the statute because that version was in effect on April 14, 2008 when the Estate filed its Form IH-5 refund claim.4 (See Appellant’s Br. at 9-13 (footnote added).) The Estate, on the other hand, maintains that the probate court properly applied the 1980 version for the two alternative reasons discussed below.
First, the Estate contends it is not the date it filed its Form IH-5 refund claim that controls, but the date it overpaid its tax, which was on November 21, 2003 when subsection (b) of the 1980 version of the statute was in effect. (See Oral Argument Tr. at 21-23, 30-31; Appellee’s Br. at 11, 14-25, 43-46.) This contention assumes that the sole requirement triggering the right to interest under the 1980 version of the statute is making an overpayment of tax that necessarily results in an erroneously or illegally collected tax.
The unambiguous meaning of the 1980 version of subsection (b) states that a refund includes both the amount of erroneously or illegally collected tax and interest on that amount from the date paid to the date refunded. I.C. § 6-4.1-10-1(b) (1980). Thus, knowing the amount of tax overpaid is prerequisite to calculating the amount of interest that may be due. The 1980 version of subsection (b), however, may not be read in isolation, but must be considered with reference to subsection (a). See State v. Adams, 583 N.E.2d 799, 800 (Ind. Ct. App. 1992) (stating “[e]ach part [of a statute] must be considered with reference to all other parts” of the statute) (citation omitted), trans. denied. Accordingly, to obtain the refund provided under the inheritance tax refund statute, subsection (a) indicates that a taxpayer must timely file a refund claim for the amount of erroneously or illegally collected tax. Indeed, cases interpreting Indiana Code § 6-4.1-10-1(a) make clear that an estate’s failure to timely file a refund claim may bar its ability to recover an erroneous overpayment of inheritance tax and any interest thereon. See Sibbitt v. Indiana Dep’t of State Revenue, 563 N.E.2d 146, 147-49 (Ind. Ct. App. 1990), trans. denied; In re Estate of Compton, 406 N.E.2d 365, 367-72 (Ind. Ct. App. 1980). Consequently, a taxpayer is not entitled to a refund with interest based solely on an overpayment of tax that results in the erroneous or illegal collection of tax, as the Estate urges. The taxpayer must also submit a timely filed refund claim. Thus, the Estate’s first argument is unpersuasive.
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Alternatively, the Estate argues that to the extent its right to receive interest depends on the date it filed its refund claim, the 1980 version of the statute still applies. (See Appellee’s Br. at 30-34.) The Estate reasons that its April 6, 2007 letter asking the Department to “advise as to refund due” and attached inheritance tax return was tantamount to filing a claim for refund because it put the Department on notice. (See Appellee’s Br. at 30-34 (footnote added).)
Both the 1980 and 2007 versions of the refund statute contain the same statute of limitations with respect to the filing of a refund claim: “the person must file the claim within three (3) years after the tax is paid or within one (1) year after the tax is finally determined, whichever is later.” I.C. § 6-4.1-10-1(a) (2007) (emphasis added); I.C. § 6-4.1-10-1(a) (1980) (emphasis added). In this case, the Estate’s inheritance tax liability was finally determined on April 8, 2008, the day the probate court determined the amount of inheritance tax due. See IND. CODE § 6-4.1-12-1 (2012) (providing that the probate court “determine[s] the inheritance tax imposed as a result of [a] resident decedent’s death and [] hear[s] all matters related to the tax determination”); accord Indiana Dep’t of State Revenue v. Estate of Parker, 924 N.E.2d 230, 235 n.1 (Ind. Tax Ct. 2010). Consequently, the Estate’s April 6, 2007 filing of its return and letter with the Department was not a valid refund claim because the probate court had not yet determined the amount of inheritance tax due as of that date.
The Estate, however, did file a valid refund claim on April 14, 2008, six days after the probate court determined its inheritance tax liability and more than nine months after the 2007 version took effect. Thus, the 2007 version of Indiana Code § 6-4.1-10-1 governed any right the Estate had to interest on its refund claim. That version of the statute provided that the Estate would receive interest on its refund claim if the Department failed to pay the refund claim within ninety days of its receipt. See I.C. § 6-4.1-10-1(b)-(c) (2007). The Department paid the claim well within that period, just twenty-nine days after receiving the claim; therefore, the probate court erred in granting the Estate interest on its refund claim and judgment interest thereon.
