Down 17% today but can't find any news on google...
This will be why - from the RNS just out:
Plus500, a leading online service provider for retail customers to trade CFDs internationally, notes the movement in its share price and market speculation following the publication on 30 November 2016 by the Cyprus Securities and Exchange Commission ("CySEC") of a series of questions and answers in a circular relevant to the CFD industry in which the Company operates.
The Company does not believe that the topics covered in the circular will have a material operational or financial impact on the Company.