This is a trust instrument (also known as a bypass or credit shelter trust) which allows a couple to reduce their estate taxes or avoid them altogether. Each spouse places their respective property in an AB trust. When the first spouse dies, the half of the property owned by that spouse passes to the beneficiaries who are named in the trust (usually these are the adult children of the couple) but with the important condition that the surviving spouse has the right to use the property for life of the spouse and is also entitled to any income generated by the property. In some limited circumstances, the surviving spouse may be able to spend the principal. The property passes to the beneficiaries of the trust when the surviving spouse dies and is not considered part of the other spouse’s estate for estate tax purposes. The use of an AB Trust limits the non-surviving spouse’s taxable estate to half the size it would have been if the property had been left directly to the spouse.