Warren proposes breaking up tech giants like Amazon

The proposal — which comes on the same day Ms. Warren will hold a rally in Long Island City, the Queens neighborhood that was to be home to a major new Amazon campus — calls for the appointment of regulators who would “unwind tech mergers that illegally undermine competition,” as well as legislation that would prohibit platforms from both offering a marketplace for commerce and participating in that marketplace.

Ms. Warren’s plan would also force the rollback of some acquisitions by technological giants, the campaign said, including Facebook’s deals for WhatsApp and Instagram, Amazon’s addition of Whole Foods, and Google’s purchase of Waze. Companies would be barred from transferring or sharing users’ data with third parties. Dual entities, such as Amazon Marketplace and AmazonBasics, would be split apart.

“I want a government that makes sure everybody — even the biggest and most powerful companies in America — plays by the rules,” Ms. Warren said in a statement. “To do that, we need to stop this generation of big tech companies from throwing around their political power to shape the rules in their favor and throwing around their economic power to snuff out or buy up every potential competitor.”