Revised Statutes of Missouri — Title X (Taxation and Revenue)
§ 145.481 RSMo — Tax return required when — executor's duty
A tax return with respect to the tax imposed by sections 145.011 to 145.995 shall be made:
(1) With respect to a resident, by every executor who is required to file a federal estate tax return;
(2) With respect to a nonresident, by every executor who is required to file a federal estate tax return if that part of the gross estate having a tax situs within the state of Missouri exceeds ten thousand dollars.
Source: official text