The UK has voted to leave the EU, and this stunning result is sending US stocks through the floor. The Dow plunged more than 600 points to the lows of the session in the final hour of the trading session on Friday.[Screen Shot 2016 06 24 at 3.19.28 PM]Investing.comThe S&P 500 was equally getting slammed, with all its ten sectors in the red. Both indexes turned negative for the year. Banking stocks were sharply lower, with Morgan Stanley falling by as much as 10%. [sp500]Investing.comThe Nasdaq had its biggest drop since November 2011, falling 196 points, or 4% . The referendum outcome means the UK will begin preparations to leave the European Union, the first member to leave the 28-member bloc since its formation in 1993. This market reaction reflects how unprecedented Brexit is, as there's no precedent to study what it means for the global economy. "It's hard to imagine that we would not be in a period of heightened volatility" leading up to the start of the Brexit negotiations in the fall, said Tony Bedikian, head of global markets at Citizens Bank. "If history is any judge, typically, with that sort of uncertainty, the risk-off trade can have some additional legs to it," he told Business Insider." Several markets are in turmoil following Thursday's vote, with some of the most stunning moves you'll ever see in developed-market indexes and currencies taking place. Headlining the proceedings is a mind-blowing drop in the British pound, which fell over 10% against the US dollar to about $1.33, a 31-year low. It's the worst single-day drop ever for the currency. [Screen Shot 2016 06 24 at 11.26.44 AM]Investing.com London's FTSE fell by as much as 4.4%.[ftse]Investing.com Germany's DAX lost more than 7% at one point. Combined, European stocks had their worst drop since 2008. [dax]Investing.comUS Treasury bonds are catching a massive bid with the 10-year Treasury yield falling to as low as 1.48% (bond prices rise when yields fall). [10year]Investing.com NOW WATCH: FORMER GREEK FINANCE MINISTER: The single largest threat to the global economy