Under what circumstances may an executor be held personally liable for the estate tax of a decedent? * If remaining assets are insufficient to pay the estate tax and no distributions have been made. If remaining assets are insufficient to pay the estate tax, distributions have been made, and the executor reasonably thought that the assets would be sufficient to cover the estate tax. If remaining assets are insufficient to pay the estate tax, distributions have been made, and the executor knew that assets would not be sufficient to cover the estate tax. Both B and C.