A testamentary trust (sometimes referred to as a will trust) is
trust which arises upon the death of the
testator, usually under his or her
will. Testamentary trusts are distinguished from
inter vivos trusts, which are created during the settlor's lifetime.For a testamentary trust, as the settlor is deceased, he will generally not have any influence over the trustee's exercise of discretion, although in some jurisdictions it is common for the testator to leave a
letter of wishes for the trustees.In practical terms, testamentary trusts tend to be driven more by the needs of the beneficiaries (particularly infant beneficiaries) than the by
tax considerations which tend to dominate considerations in inter vivos trusts.
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A trust that goes into effect when the person who establishes the trust dies.