Insufficient liquidity to pay estate tax
The federal estate tax, a 40% levy on estate values exceeding $5.49 million in 2017 (and $10.98 million for couples), is due nine months after death. (Some states apply an additional estate tax.)
Such super-wealthy clients with a lot of illiquid assets in their estate need to plan to ensure they have the cash on hand to pay any estate tax due to the government in that time frame, said Beth Shapiro Kaufman, president at law firm Caplin & Drysdale.