A corporate trust is any partnership, association or trust the beneficial interest in which is represented by transferable shares. A federal S corporation that qualifies as a Massachusetts corporate trust must file Form 3F. For additional information about taxation of corporate trusts, contact the Department of Revenue's Customer Service Bureau at 617-887-6367 or toll-free in Massachusetts at 800-392-6089. Please note when calling that, generally, corporate trusts are administered by the personal income tax sections of the Department. See also Massachusetts General Laws Ch. 62, sec. 8.