Section 121.26. Penalties for failure to file or for filing a late return

(a) If there is a failure to file a return on or before the due date prescribed on or before the date to which an extension has been granted, there shall be added to the amount required to be shown as tax on the return 5% of the amount of the tax, as the penalty, unless it is shown that the failure to file a return is due to reasonable cause and not due to willful neglect. If the failure is for more than 1 month, an additional 5% for each additional month or fraction thereof shall be added during which the failure continues, not to exceed 25% in the aggregate. In no case may the amount added be less than $5.

(b) A person who willfully fails to file a return, files a fraudulent return or attempts to evade or defeat the tax, shall be guilty of a misdemeanor and upon conviction be subject to fines or be imprisoned as provided for in the law, or both.