The weekend hasn't seemed to calm down investors, who remain jittery after the UK's vote to leave the European Union: the Dow Jones Industrial Average has lost more than 300 points this morning, exacerbating last week's 600 point dip, according to Bloomberg. The S&P 500, meanwhile, has dropped an additional 2.1 percent, though trading volume was higher than average. The Nasdaq has also taken a hit, decreasing 2.5 percent, making it lower than it's been since Feb. 29. 

CNN Money reports that British banks have been hit particularly hard by the market turmoil. Shares in Barclays and Royal Bank of Scotland dropped 8 percent this morning, briefly tripping circuit breakers that halted trading in response. Once trading resumed, Barclays lost an additional two percent and RBS lost an additional five percent. Since the initial vote, Barclays shares are now down 26 percent total, while RBS shares have lost 30 percent in value, said CNN Money. The British pound sunk further as well, having lost a total 12 percent in value since the vote. 

While news such as this is troubling, US Treasury Secretary Jack Lew urged calm, according to CNBC. While understanding that the current market turmoil is certainly far from ideal, he said it was at least orderly. He also felt that European banks are better equipped to deal with the market fallout than they were in 2008, and was confident that the British government will be able to guide the country through the transition period. He was also against US intervention in the British economy, saying it would be a destabilizing force.