Which of the following statements is incorrect regarding estate taxes?

The statement asserting that all states have an estate tax is incorrect because not all states impose an estate tax. In fact, there are several states that do not have any estate tax, which means that estate tax laws vary widely across the United States. While some states do levy an estate tax, others have opted not to implement one at all, leading to a landscape where estate tax obligations depend on the decedent's state of residence at the time of death.

The other statements are accurate. The unused federal estate tax exemption can indeed be utilized by a surviving spouse, enabling them to benefit from the deceased spouse's exemption amount, which can be significant in estate planning. The most efficient use of the federal exemption is often considered to occur during one's lifetime through gifting, which allows individuals to potentially reduce the size of their taxable estate. Finally, gifts received by a recipient are not considered taxable income; rather, they are usually exempt from income tax, though the donor may be subject to gift tax rules.