Yesterday, the entire cryptocurrency market took a significant dip, selling off from a global cryptocurrency market capitalization of US$144 billion down to US$137.5 billion.
The only news I could locate that may have caused the negative sentiment was this news about South Korea banning ICO's:
https://www.cnbc.com/2017/09/28/south-korea-bans-all-new-cryptocurrency-sales.html
Some headlines were egregiously sensational, such as "South Korea Bans Bitcoin" — which, like what happened in China, is not true. Only ICOs are banned in South Korea, and only exchanges and ICOs are banned in China.
For the most part, the crypto market rebounded to near previous levels in a few hours. Like it always does.