Dominant tech platforms like Amazon, Google and Facebook will have to tell users what their personal data is worth, according to a bill proposed by US lawmakers on Monday, Axios reports.

Senators propose the legislation only apply to companies with over 100 million users.

Firms which make money processing or collecting data would inform users about the kind of data they extract, its purposes, and—every three months—its overall value.

Someone’s monthly data value could range from $5 to $20—possibly more.

Companies would also need to annually report their user data’s aggregate value to the Securities and Exchange Commission. In turn, the Commission will develop ways of assessing data’s value across sectors, uses, and business models.

Correctly implementing this legislation may require companies trace anonymised information back to individual users, raising privacy concerns.

Tech giants claim determining how much revenue a particular user’s data generates would be difficult—data brokering is high-speed and high-volume, with data shared instantly across multiple, differently-operated platforms.

But lawmakers argue data-reliant companies evaluate their market value easily enough when arranging acquisitions, going public or budgeting internally.

We spend over two hours daily on social media alone—not counting data-rich activities like digital shopping.

Should companies tell you what your data’s worth?