Stocks dropped on Tuesday after President Donald Trump slapped sanctions on Iran's supreme leader.
Another factor at play was a report indicating Trump "feels comfortable with any outcome" from his meeting with Chinese President Xi Jinping.
According to Markets Insider, the news fanned fears of an escalating conflict with Iran and an unending trade war with China.
Optimism is fading a little and we would expect investors to perhaps take some risk off the table ahead of the meeting.
Neil Wilson, Chief market Analyst, Markets.com.