Estate Tax Return (Form 706)

In the United States, Form 706 is the federal estate tax return: the filing that reports everything a deceased person owned, everything they owed, and the value of each item, so that any estate tax due can be calculated. The executor of the estate is responsible for filing it, generally within nine months of death, with an extension available. The return is also how advisers elect portability, the mechanism that transfers a deceased spouse's unused estate tax exemption to the surviving spouse for later use.

Not every estate has to file. Broadly, a return is required when the estate's value, together with taxable gifts made during life, exceeds the federal exemption in effect for the year of death, and many estates below that line file anyway to secure portability for the survivor. Several US states also levy their own estate or inheritance taxes with separate filings, an added layer for families with homes or assets in more than one state.

Why it matters for family offices

For an ultra-high-net-worth estate, the 706 is less a form than a project. Closely held business interests, private fund positions, real estate, and art all need supportable date-of-death valuations, often from independent appraisers, and the return invites scrutiny precisely because the amounts involved are large. The quality of the filing depends almost entirely on records assembled years earlier: a clean register of entities and ownership percentages, a full history of gifts already reported on gift tax returns, and cost basis documentation for assets acquired over decades. A family office that keeps these current is quietly doing 706 preparation long before anyone needs it.

How it shows up in practice

When the founder of a family with a holding company, a dozen partnership interests, and a significant art collection dies, the executor and outside counsel begin assembling the return immediately. They need an ownership chart that is actually correct, appraisals for every hard-to-value asset, every previously filed Form 709 to reconcile lifetime gifts, and statements from accounts across multiple custodians. Where the family office has maintained a single, reconciled picture of the holdings, this is a demanding but orderly exercise. Where it has not, the nine-month clock becomes the enemy, and valuation positions may be taken under pressure that the family then lives with for years.