According to Financial Times, bitcoin surges to 300 USD, and then in last few days to 490 USD due to popularity in China of MMM by Sergei Mavrodi - a clone of the most famous Ponzi scheme in Russia he run in 1990-s -https://en.wikipedia.org/wiki/MMM_(Ponzi_scheme_company)The current version: http://mmmglobal.org/
The FT article: http://ft.com/intl/cms/s/0/ee93bc2e-82f6-11e5-8095-ed1a37d1e096.html