An antivirus program used by hundreds of millions of people around the world is selling highly sensitive web browsing data to many of the world's biggest companies, a joint investigation by Motherboard and PCMag has found. Our report relies on leaked user data, contracts, and other company documents that show the sale of this data is both highly sensitive and is in many cases supposed to remain confidential between the company selling the data and the clients purchasing it.

The documents, from a subsidiary of the antivirus giant Avast called Jumpshot, shine new light on the secretive sale and supply chain of peoples' internet browsing histories.