Britain is exiting the European Union

If certainty is the friend of the investor, uncertainty is definitely the opposite. The surprising Brexit vote caused investors to quickly move towards traditional safe havens. Currency markets experienced very high volatility as the British pound plunged and the Dollar and Yen rose. Perhaps the biggest concern of investors may be what the Brexit vote may foretell about the influence of populist political movements on other democratic governments.

https://www.nytimes.com/2016/06/25/business/international/brexit-financial-economic-impact-leave.html