(a) Except as provided by Subsection (b), a taxpayer who is required by this title to keep records shall keep those records open to inspection by the comptroller, the attorney general, or the authorized representatives of either of them for at least four years.
(b) A taxpayer is required to keep records, as provided by Subsection (c) with respect to the taxpayer’s claim, open for inspection under Subsection (a) for more than four years throughout any period when:
(1) any tax, penalty, or interest may be assessed, collected, or refunded by the comptroller; or
(2) an administrative hearing is pending before the comptroller, or a judicial proceeding is pending, to determine the amount of the tax, penalty, or interest that is to be assessed, collected, or refunded.

(c) A taxpayer shall produce contemporaneous records and supporting documentation appropriate to the tax or fee for the transactions in question to substantiate and enable verification of the taxpayer’s claim related to the amount of tax, penalty, or interest to be assessed, collected, or refunded in an administrative or judicial proceeding. Contemporaneous records and supporting documentation appropriate to the tax or fee may include, for example, invoices, vouchers, checks, shipping records, contracts, or other equivalent records, such as electronically stored images of such documents, reflecting legal relationships and taxes collected or paid.
(d) This section prevails over any other conflicting provision of this title.