If President-elect Donald Trump carries through on his campaign proposal to create a national registry of Muslims living in the U.S., the data his administration would need to accomplish this task may already be available via data broker services, according to a report Tuesday from media and technology company Vocativ.

Vocativ speculates that the Trump Administration would not necessarily have to rely on a secretive FISA (Foreign Intelligence Surveillance Act) court order to compel major companies like Facebook or Google to turn over data that could help build a Muslim database. Rather, U.S. agencies could potentially aggregate personally identifying information from data brokers that collect and openly sell information on people based on their web browsing and shopping behavior. 

Vocativ noted that there are thousands of such companies – Acxiom, Datalogix and Experian among them – that typically use tracking beacons embedded into web pages “to profile people based on demographics like race, age, and religion, as well as their political views, medical conditions, consumer preferences, and more.” The article also warned that threat intelligence companies like Recorded Future or Palantir could also be a viable source of data that could help build a Muslim registry.

A spokesperson for the data broker Axciom told Vocativ that the company would not help the government build a database targeted to a religious, racial or political group, and Recorded Future co-founder and CEO Chris Ahlberg told Vocativ that his company would not provide information if it had reason to believe the data was being used to target Muslims, immigrants or dissidents.