§ 139.100 RSMo — Collection of penalty for delinquent taxes — payment agreement (St. Louis County) — settlement — penalty for violation — payment of taxes by mail deemed paid, when

1. (1) If any taxpayer shall fail or neglect to pay to the collector his taxes at the time required by law, then it shall be the duty of the collector, after the first day of January then next ensuing and in the absence of an agreement entered into pursuant to subdivision (2) of this subsection, to collect and account for, as other taxes, an additional tax, as penalty, the amount provided for in section 140.100 .

(2) For property tax liabilities incurred on or after January 1, 2020, and on or before December 31, 2020, the collector of any county with a charter form of government and with more than nine hundred fifty thousand inhabitants may enter into an agreement with any taxpayer for the payment of any amount of tax not paid at the time required by law, including a waiver or reduction of penalties and interest on such taxes, provided that any such agreement shall require such taxes to be paid to the collector or postmarked by no later than January 8, 2021.

(3) For any taxpayer that has paid penalties and interest on property tax liabilities not paid at the time required by law, and such penalties and interest are subsequently reduced or waived through an agreement entered into pursuant to subdivision (2) of this subsection, that portion of penalties and interest paid and subsequently reduced or waived may be credited to the taxpayer on such taxpayer's tax liability for the subsequent year. The county may reduce on a pro rata basis any distributions to taxing jurisdictions by the amount of any penalties and interest from late payments from the 2020 tax year that were collected and distributed, but were then subsequently reduced or waived pursuant to subdivision (2) of this subsection.

2. Collectors shall, on the day of their annual settlement with the county governing body, file with governing body a statement, under oath, of the amount so received, and from whom received, and settle with the governing body therefor; but, interest shall not be chargeable against persons who are absent from their homes, and engaged in the military service of this state or of the United States. The provisions of this section shall apply to the City of St. Louis, so far as the same relates to the addition of such interest, which, in such city, shall be collected and accounted for by the collector as other taxes, for which he shall receive no compensation.

3. Whenever any collector of the revenue in the state fails or refuses to collect the penalty provided for in this section on state and county taxes, it shall be the duty of the director of revenue and county clerk to charge such collectors with the amount of interest due thereon, as shown by the returns of the county clerk, and such collector shall be liable to the penalties as provided for in section 139.270 .

4. For purposes of this section and other provisions of law relating to the timely payment of taxes due on any real or personal property, payments for taxes due on any real or personal property which are delivered by United States mail to the collector, the collector's office, or other officer or office designated by the county or city to receive such payments, of the appropriate county or city, shall be deemed paid as of the postmark date stamped on the envelope or other cover in which such payment is mailed. In the event any payment of taxes due is sent by registered or certified mail, the date of registration or certification shall be deemed the postmark date. No additional tax or penalty shall be imposed under this section on any taxpayer whose payment is delivered by United States mail, if the postmark date stamped on the envelope or other cover containing such payment falls within the prescribed period or on or before the prescribed date, including any extension granted, for making the payment or if the postmaster for the jurisdiction where the payment was mailed verifies in writing that the payment was deposited in the United States mail within the prescribed period or on or before the prescribed date, including any extension granted, for making the payment, and was delayed in delivery because of an error by the United States postal service and not because of an error by the taxpayer. In the absence of a postmark, or if the postmark is illegible or otherwise inconclusive, the collector may use the collector's judgment regarding the timeliness of the payment contained therein and shall document such decision.