Mo. Rev. Stat. § 355.026: Effective date of documents.

1. Except as provided in subsection 2 of this section, a document is effective:

(1) On the date it is filed, as evidenced by the secretary of state's endorsement on the original document; or

(2) On the date specified in the document as its effective date, provided that a document shall not be effective prior to the date it is filed in the office of the secretary of state.

2. A document may specify a delayed effective date, and if it does so the document becomes effective on the date specified. If a delayed effective date is specified, the document is effective on that date. A delayed effective date for a document may not be later than the ninetieth day after the date.