When does the unlimited marital deduction apply when there is an out right bequest of stock?

The unlimited marital deduction applies when one spouse bequeaths property, such as stock, to the other spouse at death without incurring federal estate tax. This deduction enables the transfer of assets between spouses to occur without tax consequences, provided the recipient spouse is a U.S. citizen. However, if the bequest is made to a non-citizen spouse, the unlimited marital deduction does not apply, and there are different rules regarding the amount that can be transferred tax-free.