The American Taxpayer Relief Act (ATRA) made estate tax law permanent following more than a decade of constant change. Following ATRA, the estate tax remains one of the most progressive parts of the tax code. In 2013, estates with gross assets exceeding $20 million will account for nearly three-fourths of the total estate tax revenue. About one-fifth of the burden will fall on estates valued between $10 million and $20 million, while just 7 percent will come from estates worth less than $10 million.