A release embargo is the rule that a statistic may not be reported before its scheduled publication time, even by people who already hold it. Statistical agencies and central banks give accredited journalists — and in some systems named officials — advance sight of a release under embargo so that coverage can be prepared, and everything is published to everyone at the stated second.
The arrangement exists to make the release simultaneous rather than staggered, which is why breaches are treated seriously and access is withdrawn when they happen. Some agencies have narrowed or ended pre-release access precisely because holding a market-sensitive number early is an advantage nobody can audit. Each publisher sets out its own current practice and lock-up arrangements in its release policy, which is the only reliable place to check what applies to a given statistic.
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Guide
How to Read an Economic Release Beyond the Headline
The number a calendar shows is one line of a document that usually runs to dozens of pages. What the rest of it holds, which parts change the meaning of the headline, and what no release can tell you.