It is allowed because most companies rely on publicity to market their products and services. Moreover, it is acknowledged that the public should be informed on a timely basis about material developments. To determine what is permitted and what isn't, read the release. If anything suggests it will enhance the selling effort, it may raise unnecessary problems. If so, it is unlikely that anyone will assert that the disclosure will stimulate the selling effort.
Historical information is more acceptable than forecasts.
If the company routinely issues a press release when it signs a contract, an argument can be made for this release. If releases on contracts only appeared sporadically in the past, a release is less defensible. The information's significance counts. While a routine release might pass, if the contract is more important than other contracts, the lawyers may oppose disclosure. When the lawyers are reluctant to issue a release, all hope is not lost.