Estate tax apportionment is easy in theory but can be unforgiving in practice creating a number of challenges and, if you are not careful, unanticipated consequences. This session will provide a practical view on how apportionment using different formulas and concepts will significantly impact trust funding and potentially the entire estate plan. The presentation will focus on the choice of funding formulas and tax apportionment clauses, including critical factors to consider, as well as various challenges which can occur with hard to value assets, IRAs, and the failure to fund at the first death (such as the so-called "Portability Tax Apportionment Trap") with examples of apportionment calculations under different scenarios and the ultimate impact on beneficiaries. The session will also include a discussion concerning the income tax issues and consideration in funding.