The federal estate tax currently affects only the richest families in America. Under legislation passed by Congress on New Year's Day 2013, the estate tax exemption was made permanent at the $5 million 2012 rate, but adjusted for inflation each year. Of course, calling the tax law "permanent" doesn't mean Congress couldn't change it again.
In 2017, every person may leave or give away up to $5.49 million without owing any estate tax. As a practical matter, that means that under the new rules about 99.5% of all estates will NOT owe any federal gift/estate tax. The exemption amount is indexed for inflation each year. Unlike legislation enacted in the last several years, there is no sunset provision for these amounts; indexed for inflation, they will stay in force until Congress changes them again.
One popular feature of the current estate tax law is that spouses can combine their estate tax exemptions, effectively letting married couples give away or leave almost $11 million without owing tax. The new law makes this feature, called “portability” by tax experts, permanent.
Here’s how it works: If the first spouse to die doesn’t use up his or her individual gift/estate tax exemption, the surviving spouse can use what’s left. That gives the couple a total exemption of twice the individual exemption amount. They can share that total exemption amount in the way that provides the greatest tax benefit. For example, if each member of a couple has $4 million in assets, and the first one to die leaves everything to the other, no estate tax is owed because property left to a spouse is tax-free. When the survivor dies and leaves $8 million ($4 million plus the $4 million inherited from the other spouse) to their children, no estate tax will be due, even though the estate is over the exemption amount, because the estate can use some of the first spouse’s unused exemption.
To take advantage of the portability rule, an estate tax return must be filed when the first spouse dies--even if no tax will be due. As commentators have pointed out, this means the IRS must process returns that don't provide any tax revenue, and taxpayers must pay experts to prepare these very complicated tax returns.
On very large estates subject to the tax, the gift/estate rate is now 40%, lower than the rates in almost every year since the 1930s.
This rate also applies to the generation-skipping transfer tax. That is a federal tax that is imposed on large transfers that skip a generation (for example, a gift from a grandparent to a grandchild) in an attempt to avoid estate tax.