US spy agencies are buying and selling Americans' personal data, creating a huge threat to privacy, a stunning new report revealed on Monday. 

The offerings on have grown from basic address history and demographic information to piles of data generated smartphone devices and apps, social-media platforms, automobiles and location trackers such as fitness watches, the Wall Street Journal reported.

That detailed information can now 'cause harm to an individual's reputation, emotional well-being, or physical safety,' said a report commissioned by Director of National Intelligence Avril Haines.

It urged US intelligence agencies to develop better policies, procedures and safeguards around what is known as commercially available information, or CAI.

The CAI market is loosely regulated when it comes to the buying and selling of data. 

The report was requested by Democratic Senator Ron Wyden of Oregon, a member of the Senate Intelligence panel.

'This review shows the government's existing policies have failed to provide essential safeguards for Americans' privacy, or oversight of how agencies buy and use personal data,' Wyden said in a statement.

He urged President Joe Biden's administration to create guidelines around the handling of the information.

'The executive branch must exercise much stronger oversight of this practice, issue guidance to agencies about the legal status of commercial data, and provide transparency to the American people about how it interprets the law,' Wyden said.

The study was the first known attempt by the U.S. government to examine comprehensively how federal agencies acquire, share and use commercially available data sets that are often compiled with minimal awareness by the public that its data is being collected and resold, the Journal reported.