Many older estate plans were drafted using old trust tax formulas that differ significantly from today’s rules. At the time, the planning may have been exactly right. But a formula that made sense years ago may now create unnecessary complexity or an unintended result.
This is especially true for older revocable trusts that contain mandatory funding formulas. These formulas were often designed to divide assets after the first spouse’s death between a marital trust and a bypass trust, sometimes called a credit shelter trust or family trust.
When estate tax exemptions were much lower, and portability did not exist, these formulas were often essential. They helped preserve the first spouse’s estate tax exemption and reduce estate tax at the surviving spouse’s later death.
Today, the tax environment is different. Federal estate tax exemptions are much higher than they were for many older plans, and portability may allow a surviving spouse to use the deceased spouse’s unused exemption if the proper estate tax return is filed. As a result, some older formulas may force assets into trusts even when the original tax rationale is no longer as important.
That does not mean bypass trusts are obsolete. They can still serve important purposes. They may protect assets from remarriage risk, creditor claims, financial exploitation, future changes in estate tax law, or disputes between a surviving spouse and children from a prior relationship. They may also preserve generation-skipping transfer tax planning in ways portability does not.
The problem is not that old formulas are always bad. The problem is that they often operate automatically.
If the trust requires specific old trust tax formulas to be followed, the trustee may not be free to ignore them simply because the family would prefer a different result. Once the first spouse dies, the issue shifts from planning to administration. Beneficiaries may have legal rights, trustees may have fiduciary duties, and changing the structure may require formal legal authority.
That is why these provisions should be reviewed before they are needed.
A trust tax formula may need attention if it was drafted before portability, before major estate tax exemption changes, or before the family’s current asset structure developed. It should also be reviewed if the family includes children from prior relationships, a surviving spouse with changing financial needs, or beneficiaries who may later disagree about access to trust assets.
Old tax formulas are not just technical provisions. They can determine who controls assets, who receives income, who has access to principal, and how much flexibility the surviving spouse and beneficiaries have after death.
A formula designed to save tax years ago may still be valuable. But it should not be assumed. It should be reviewed.
