Ann: BARD1 Signs Option Agreement for Type 3C Diabetes Test, page-20

Well, its both a specific requirement and a black art.

The specific requirement is that when a listed company becomes aware of an event that could materially affect the share price they should announce it to the market - this is their continuous disclosure obligation.

But, before announcements are released they need to be checked and approved, this might delay their release (or at least provide a plausible reason why they weren't release immediately) because they also have a requirement to not make deceptive, misleading or factually incorrect statements.

It doesn't take much imagination to work out how these two requirements could be played to provide considerable wriggle room.

IMO