The European Union has listed six tech giants as so-called "gatekeepers" under a new law designed to ensure fair competition in digital markets.
The EU says the companies are Google's parent firm Alphabet, Amazon, Apple, TikTok operator ByteDance, Meta, and Microsoft.
Under the Digital Markets Act, tighter regulations will be imposed from early next year on 22 core platform services run by the companies.
They will no longer be able to give preference to their own products and services when displaying them on their platforms. The firms will be prohibited from forcing app developers to use their payment systems.
The operators will also be required to give advance notice to EU regulators when acquiring rival firms.
Violators could face fines of up to 10 percent of their annual worldwide revenues.
The EU hopes that the new regulations will prevent tech giants from abusing their dominant market positions to impose unfair conditions on consumers.