Per the IRS, an estate tax is a tax on the transfer of property upon death. An estate tax considers the fair market value of all the property within one’s estate, and not what the assets were originally purchased for. The total of these items is known as the Gross Estate, and can include cash, securities, ownership interests in either a business or real estate, annuities, among other asset classes. As of 2019, a filing is only required for estates with a gross assets and prior taxable gifts above $11,400,000.
Once the Gross Estate has been determined, one may be able to take deductions to determine the actual taxable amount of the estate. These include mortgages, estate administration expenses, and property that is given to eligible charities. Note, that property passed to a living spouse may be transferred tax free.
Source: https://www.irs.gov/businesses/small-businesses-self-employed/estate-tax
