This allows a married couple to postpone all estate taxes until the second death. For larger estates this may result in higher taxes at the second death.

The U.S. tax code limits the amount of assets one can transfer to another (either during life or after death) without triggering transfer taxes. There are some exceptions to this rule – the largest being the unlimited marital deduction that allows spouses to give each other (during life or after death) an unlimited amount of assets without transfer taxation.

Consequently, many estate plans and wills specify that the first to die will leave all or nearly all of his/her assets to the surviving spouse. This way, no wealth is lost to estate taxes at the first death. Those assets, of course, will be subject to estate tax upon the death of the survivor.

The unlimited marital deduction makes estate planning rather simple for those estates that will not be subject to estate tax. But for larger estates, the unlimited marital deduction may increase taxes at the second death. Remember, the unlimited marital deduction does not avoid estate taxation; it just postpones taxation.

Larger estates should consider more advanced estate planning techniques such as creating special trusts like the Credit Shelter Trust and using the unlimited marital deduction on only a portion of all estate property. The marital deduction is limited in those cases where the surviving spouse is not a U.S. citizen.

It is wise to consult an estate attorney or advisor about the advantages and disadvantages of the unlimited marital deduction, portability, and credit shelter trusts in order to see which technique(s) might be best for any specific estate.