Yet “AI watermarking” is a misleadingly simple name for what Article 50 of the EU AI Act now requires. AI system providers must build machine-readable marking into certain outputs. There is no single EU watermarkThe starting point is the AI Act itself. It sits with the company that develops an AI system, or has one developed, and places it on the EU market under its name. Generative AI systems placed on the market before 2 August receive a limited grace period until 2 December 2026 for the provider-side machine-readable marking duty.