A. The federal estate tax applies to the value of all assets that a decedent owns or controls at death, regardless of the type of account in which the asset is held.
You might want to consider, though, that only assets held in certain types of accounts can be efficiently transferred. For example, retirement accounts, such as 401(k)s or traditional IRAs, cannot be transferred to a third party during the account holder's lifetime without triggering income taxes and possibly penalties.
For this reason, most gifting strategies focus on transferring nonqualified, or taxable, assets, such as assets in a brokerage account or real estate. For people with a disproportionate amount of their wealth in retirement accounts, planning strategies shift to improving the income tax efficiency of the transferred accounts to reduce the beneficiary's income tax burden. Roth conversions, for example, may be an effective strategy to accomplish this goal. But, for estate tax purposes, the entire value of the converted Roth account will be included in the owner's estate.