U.S. stock markets were expected to open lower on Monday on heightened fears of a possible Greek exit from the euro zone after the country's voters rejected austerity measures demanded in return for much-needed cash.
Japan's blue-chip Nikkei closed down just over 2 percent, while European shares opened broadly lower as investors reacted to Sunday's overwhelming 'No' vote by Greek voters.
That set the tone for trade in U.S. stock futures, with Dow Jones industrial average futures down more than 100 points in early London trade – indicating a weak open for Wall Street shares which reopen after being closed Friday for the Independence Day holiday.
"After the comprehensive victory for the 'No' camp in yesterday's Greek referendum, eventual 'Grexit' now looks more likely than not," analysts at Daiwa Capital Economics said in a note. "The response of policymakers over the next 48 hours will be key."
"Unless a deal can be reached swiftly the Greek banks and the Greek government will simply run out of funds making the introduction of a parallel currency soon inevitable," they added.