What is a press embargo?

An embargo is an agreement that information supplied to journalists in advance will not be published until a specified time. The source provides material early; the recipient agrees to hold it.

Why they exist. They serve both sides, which is why the convention persists.

For journalists, an embargo provides time to actually do the work — read a research paper properly, seek independent expert comment, prepare graphics, and file considered copy rather than a rushed summary. Embargoed access is one of the main reasons science and financial coverage is as accurate as it is.

For sources, it ensures coordinated release, so the story appears everywhere simultaneously rather than dribbling out, and it reduces the chance of being misreported by someone with twenty minutes to file.

Common uses: scientific journals releasing papers to press ahead of publication; companies distributing results or product announcements; governments circulating budgets and official reports; and organisations issuing speeches "check against delivery" before they are given.

What happens if one is broken. There is no legal force in most cases — an embargo is a professional convention backed by exclusion. An outlet that breaks one is typically cut off from future embargoed material, which is a serious commercial penalty and generally sufficient enforcement.

The criticisms are real. Embargoes give sources significant control over the news cycle and can discourage sceptical coverage, since access depends on the relationship. Journal embargoes have been argued to encourage churn — a wave of near-identical articles at the same moment based on the same press release. And material sometimes leaks anyway, at which point the outlets that honoured the agreement are the ones penalised.

Nothing binds someone who never agreed. A journalist who obtains the information independently is free to publish, which is a distinction sources sometimes misunderstand.