Both equities and bonds fell in tandem as the markets priced in an increased likelihood of a rate rise in the US (circa 30% chance of a hike in September) along with fears over central bank policy changes.
The Federal Reserve is playing cat & mouse with the markets. They are suggesting, via comments from members, that a rate hike is imminent. Recent data may prevent this happening and a selloff in equities and bonds may well lead them to delaying what surely must be the inevitable.
Perhaps more of a worry to markets is that the European and Japanese central banks are hinting that they may well be reaching the end of quantitative easing. There is weight behind the thinking that a lowering of interest rates and continued buying of government bonds will be replaced by fiscal stimulus.