Mo. Rev. Stat. § 143.581
Every partnership having a resident partner or having any income derived from sources in this state, determined in accordance with the applicable rules of section 143.181 as in the case of a nonresident individual, shall make a return for the taxable year setting forth all items of income, gain, loss, and deduction, and the names and addresses of the individuals whether residents or nonresidents who would be entitled to share in the net income if distributed and the amount of the distributed share of each individual and such other pertinent information as the director of revenue may prescribe by regulations and instructions. Such return shall be filed on or before the fifteenth day of the fourth month following the close of each taxable year. For purposes of this section, "taxable year" means a year or period which would be a taxable year of the partnership if it were subject to tax under sections 143.011 to 143.996.
§ 143.581, RSMo
Effective 1/1/1973