Section 65National Internal Revenue Code of 1997 (Republic Act No. 8424), Sec. 65

Fiduciary Returns. - Guardians, trustees, executors, administrators, receivers, conservators and all persons or corporations, acting in any fiduciary capacity, shall render, in duplicate, a return of the income of the person, trust or estate for whom or which they act, and be subject to all the provisions of this Title, which apply to individuals in case such person, estate or trust has a gross income of Twenty thousand pesos (P20,000) or over during the taxable year.

Such fiduciary or person filing the return for him or it, shall take oath that he has sufficient knowledge of the affairs of such person, trust or estate to enable him to make such return and that the same is, to the best of his knowledge and belief, true and correct, and be subject to all the provisions of this Title which apply to individuals: Provided, That a return made by or for one or two or more joint fiduciaries filed in the province where such fiduciaries reside; under such rules and regulations as the Secretary of Finance, upon recommendation of the Commissioner, shall prescribe, shall be a sufficient compliance with the requirements of this Section.