Last Updated Jun 27, 2016 2:39 PM EDT
Like markets overseas, Wall Street headed lower Monday amidst continued uncertainty about what's next after U.K. voters decided to leave the European Union.
The Dow shed 288 points, or 1.7 percent, to 17,113 at 2:33 p.m. ET. The Nasdaq lost 116 points, or 2.5 percent, to 4,592. And the S&P 500 declined 39 points, or 1.9 percent, to 1,998.
Monday's losses followed a brutal Friday after British voters narrowly voted for Brexit a day earlier. The fallout was swift - markets across the globe tumbled, the pound fell to a low not seen since the 1980s, and gold prices advanced. The Dow shed 611 points Friday, or 3.4 percent; the S&P lost 76 points, or 3.6 percent, wiping out gains for the year.
Following the referendum, U.K. Prime Minister David Cameron - who had campaigned against a Brexit - announced he'd resign later this year, and that his successor should initiate the exit process, which could take two years. But some EU members have said they wish for a speedy exit to ease uncertainty.
Cameron told Parliament on Monday the U.K. will not trigger formal EU exit talks at this stage. He added that the referendum result is "not the outcome I think is best for Britain" but said the result must be respected and implemented in the "best possible way."
Ratings agency Standard and Poor's stripped the U.K. of its top credit grade, from AAA to AA. S&P said vote is a "seminal event" that "will lead to a less predictable, stable and effective policy framework in the U.K."
Standard and Poor's also cited "risks to the constitutional and economic integrity of the U.K." as Scotland's strong vote to remain in the EU could raise the prospect of another referendum on Scottish independence.