(42)In view of the specificities of sovereign ratings and in order to reduce the risk of volatility, it is appropriate and proportionate to require credit rating agencies to publish those ratings only after close of business of the trading venues established in the Union and at least one hour before their opening. On the same basis, it is also appropriate and proportionate that, at the end of December, credit rating agencies should publish a calendar for the following 12 months setting the dates for the publication of sovereign ratings and, corresponding thereto, the dates for the publication of related rating outlooks where applicable. Such dates should be set on a Friday. Only for unsolicited sovereign ratings should the number of publications in the calendar be limited between two and three. Where this is necessary to comply with their legal obligations, credit rating agencies should be allowed to deviate from their announced calendar, while explaining in detail the reasons for such deviation. However, such deviation should not happen routinely.