Tex. Tax Code § 202.301

Sec. 202.301. DELINQUENT TAXES: PENALTY. (a) A person who fails to pay the tax imposed by this chapter when due forfeits five percent of the amount due as a penalty, and if the person fails to pay the tax within 30 days after the day on which the tax is due, the person forfeits an additional five percent.

(b) The minimum penalty under this section is $1.

(c) Notwithstanding Subsections (a) and (b), a person is not subject to a penalty under Subsection (a) if:

(1) the delinquent tax results from the person's filing of an amended report with the comptroller for a timely filed original report under Section 202.201 or 202.202;

(2) the person timely paid the full amount of tax due as indicated in the original report;

(3) the amount of additional tax due as a result of all amended reports for the original report does not exceed 25 percent of the tax due as indicated in the original report;

(4) the person resolves all errors identified by the comptroller on the amended or original report that could affect the amount of tax due on that report not later than the 60th day after the date on which the amended or original report, as applicable, is filed; and

(5) the person files the amended report not later than the 730th day after the date on which the original report was due and remits the full amount of the additional tax due with the amended report.