Cal. Revenue and Taxation Code § 45160

(a) Any person whose estimated fee liability under this part averages twenty thousand dollars ($20,000) or more per month, as determined by the board pursuant to methods of calculation prescribed by the board, shall remit amounts due by an electronic funds transfer under procedures prescribed by the board. (b) Any person whose estimated fee liability under this part averages less than twenty thousand dollars ($20,000) per month may elect to remit amounts due by electronic funds transfer with the approval of the board. (c) Any person remitting amounts due pursuant to subdivision (a) or (b) shall perform electronic funds transfer in compliance with the due dates set forth in Article 1 (commencing with Section 45151). Payment is deemed complete on the date the electronic funds transfer is initiated if settlement to the state’s demand account occurs on or before the banking day following the date the transfer is initiated. If settlement to the state’s demand account does not occur on or before the banking day following the date the transfer is initiated, payment is deemed to occur on the date settlement occurs. (d) Any person remitting fees by electronic funds transfer shall, on or before the due date of the remittance, file a return for the preceding reporting period in the form and manner prescribed by the board. Any person who fails to timely file the required return shall pay a penalty of 10 percent of the amount of fees with respect to the period for which the return is required. (e) Any person required to remit fees pursuant to this article who remits those fees by means other than appropriate electronic funds transfer shall pay a penalty of 10 percent of the fees incorrectly remitted. (f) Any person who fails to pay any fee to the state or any amount of fee required to be collected and paid to the state, except amounts of determinations made by the board under Article 2 (commencing with Section 45201), within the time required shall pay a penalty of 10 percent of the fee or amount of fee, in addition to the fee or amount of fee, plus interest at the modified adjusted rate per month, or fraction thereof, established pursuant to Section 6591.5, from the date on which the fee became due and payable to the state until the date of payment. (g) In determining whether a person’s estimated fee liability averages twenty thousand dollars ($20,000) or more per month, the board may consider returns filed pursuant to this part and any other information in the board’s possession. (h) The penalties imposed by subdivisions (d), (e), and (f) shall be limited to a maximum of 10 percent of the fees due for any one return. Any person remitting fees by electronic funds transfer shall be subject to the penalties under this section and not Section 45153. (i) The board shall promulgate regulations pursuant to Chapter 3.5 (commencing with Section 11340) of Part 1 of Division 3 of Title 2 of the Government Code for purposes of implementing this section.