In the U.S. it is called Regulation FD as in Full Disclosure"...
With the rise of Internet-based brokerage services in the 1990s, there was also an increased demand by investors for access to information that companies had historically shared with institutional investors but not the general public. This led to Regulation Fair Disclosure, which requires companies to release “material information” to the public at the same time it is disclosing it to institutional investors. If the disclosure to the institutional investor is accidental, the company has to quickly inform the public. But if the disclosure is planned, such as a quarterly conference call with analysts to discuss earnings, then public disclosure must be simultaneous.
Companies can meet that requirement in a number of ways, such as by filing a Form 8-K with the SEC that contains the information to be disclosed, or by opening the conference call to the public...."