The three wealthiest U.S. families are the Walton’s of Walmart, the Mars candy family, and the Koch brothers, heirs to the country’s second largest private company, the energy conglomerate Koch Industries. These are all enterprises built by the grandparents and parents of today’s wealthy heirs and heiresses. These three families own a combined fortune of $348.7 billion, which is four million times the median wealth of a U.S. family.

The just-released Panama Papers—filled with titillating details involving the shady dealings of world leaders and violent traffickers of drugs and slaves—should give a strong boost to US and global campaigns to crack down on these global secrecy jurisdictions and practices.