NEW YORK ( TheStreet) -- Monday's stock selloff picked up speed in the final hour of trading, a warning sign that investors can expect more turmoil from Greece's debt crisis.
The S&P 500 declined 2.08%, the Dow Jones Industrial Average fell 1.95%, or 350 points, and the Nasdaq slid 2.40%. The Dow is down 1.1% for the year, while the S&P 500 gave up almost all of its gains year-to-date.
With no deal in place, Greece is likely to default on its $1.7 billion payment due to the International Monetary Fund on Tuesday unless an 11th hour deal is made.
Talks broke down over the weekend between Greece and its creditors, but German Chancellor Angela Merkel and French President Francois Hollande said they're willing to continue negotiations with the debt-laden nation even after its July 5 referendum, according to Bloomberg. That vote will allow citizens to decide if Greece should exit the eurozone.
On Sunday, it was announced that banks in Greece would remain closed until July 6 with ATM withdrawal limits of 60 euros a day. One Greek official, however, told CNBC that banks are set to open on Thursday.
Meanwhile, Standard & Poor's lowered Greece's long-term credit rating to "CCC minus" from "CCC" and pegs the odds of a "Grexit" at 50%.
"In our view, the Greek government's decision to hold a national referendum on official creditors' loan proposals indicates that Prime Minister Alexis Tsipras will prioritize domestic politics over the country's financial and economic stability, commercial debt service, and membership of the eurozone," Standard & Poor's said.