Estate trust is a trust established by one spouse for the benefit of the surviving spouse. Such trusts are also established for qualifying a deceased spouse's property for the marital deduction. Marital deductions are federal tax deductions allowed for lifetime and testamentary transfers from one spouse to another.(26 USCS). In estate trusts, the assets of the estate trust are paid to the estate of the surviving spouse if the donor provides that, at the surviving spouse's death, any accumulated income and remaining principal must be distributed to the surviving spouse’s estate.