WASHINGTON—Legislation to bar internet companies from favoring their own products on their platforms is gaining more support, in what could be a potential threat to the business models of tech giants like Amazon.com Inc. and Apple Inc.
Bipartisan Senate legislation announced Thursday would prohibit dominant platforms from favoring their own products or services, a practice known as self-preferencing. It would also bar these dominant platforms from discriminating among business users in a way that materially harms competition.