On 1 May 2013, the new Swiss rules on insider dealing and market manipulation entered into force. They bring about a fundamental change in Swiss administrative and criminal law and will have a significant impact on Swiss practice. Accordingly, issuers, financial institutions, advisers and other affected persons (meaning any other market participant in Switzerland) should familiarize themselves with the new rules and review their internal guidelines, procedures and standard forms to ensure compliance with these new rules and to make appropriate use of the safe harbours available under the new law. Further regulation will follow shortly; in particular, a revised FINMA circular on market behaviour rules, which will apply to all market participants, is expected to enter into force on 1 August 2013.