Amazon’s business model, in which it competes with merchants who are also customers, merits a technology industry version of Glass-Steagall, the Depression-era law that split consumer and investment banks, Sen. Elizabeth Warren, D-Mass., said Thursday.

Her perspective mirrors the stance of antitrust activists who argue that tech giants, including the e-commerce firm founded by Jeff Bezos, have created monopolies by building and controlling platforms on which they vie for business with their users.