Greek voters overwhelmingly rejected austerity measures imposed by creditors in the country’s referendum yesterday, according to preliminary estimates, setting the nation on course for a potential withdrawal from the common currency. Banks did not open today in the wake of the vote and new, lower, ATM withdrawal limits were imposed. Greek Finance minister Yanis Varoufakis, who had campaigned strenuously in favor of a “no” vote, resigned in a surprising move that some analysts anticipate presages a major shift in Prime Minister Alexis Tsipras’s cabinet. European Union President Donald Tusk has called on EU leaders to meet in an emergency summit in response to the situation in Athens.

China seeks to tame volatility. Today Chinese exchange officials and regulators agreed to suspend initial public offerings and unveiled a roughly $20 billion market stabilization fund after earlier failed attempts to lessen panic in equity markets. In response, equities in China experienced a historically volatile session with the Shanghai Stock Exchange Composite index opening up 8 percent, only to fall into negative territory within hours. The benchmark index for A-shares is now nearing a 30 percent decline level from the all-time highs reached last month.

Major merger in health insurance underway. Hartford, Connecticut–based insurance company Aetna has agreed to acquire Louisville, Kentucky–headquartered insurance and medical provider Humana in a deal valued at $37 billion, according to an announcement released Friday. The acquisition price constitutes a 23 percent premium to Humana’s closing price prior to the announcement. The combined cash and stock purchase constitutes the largest merger on record in the health insurance industry.

Oil markets sell off. West Texas Intermediate crude oil futures fell in electronic trading this morning, with front-month contracts down by more than $2.50 per barrel. Analysts expected more sympathetic selling in energy markets as the U.S. dollar strengthens in response to a looming Greek exit.

Rolls Royce delivers another warning. Manchester, U.K.–based auto and aerospace manufacturer Rolls-Royce Holdings today announced that it will suspend its share repurchase program, as company management issued another warning that profits at the firm are deteriorating. This marks the second time that the company has guided investor expectations lower as new management has not yet turned around the company’s aircraft engine division.

Portfolio Perspective: A Greek Inspired Sell-off Presents Buying Opportunities For European Stocks — Nigel Green, deVere Group

Given the broader implications of how Greece’s socking a bloody nose to Europe affects other debt-shackled euro zone nations’ predilections against remaining in the common currency, there is likely to be a widespread uncertainty gripping the markets. This predicted stock market sell-off and the resulting drop in prices will, of course, create an important buying opportunity, especially for those investors who have a long-term perspective.

With negotiations potentially taking an extended period of time, the uncertainty is likely to be protracted, meaning the sell-off and buying opportunity could also last some time — unlike last week, when markets bounced back quickly. Any buying opportunity may be particularly attractive in light of the recovery across much of the euro zone.

Nigel Green is founder and CEO of deVere Group in London.