For four hours yesterday, Greece turned into Albania at the time of Enver Hoxha: It disappeared off the world’s financial map. Striking employees at the Bank of Greece, in a surprise takeover of the computer records department at Holargos, barred entry to everyone, including emergency staff. In conjunction with technical problems with the computer server, the impossible, for a mature market, happened: All systems went down for four hours. Given that the Athens stock exchange is entering a period of supervision and faces the risk of being downgraded, this event could well deliver the final blow to the Greek bourse. Foreign investors, who keep a close eye on every development in global markets, will be unable to place their trust in a market that shuts down so suddenly on the whim of a group of unionists. Much will be decided today, but the big question is whether ATHEX will remain on the map of mature markets or be relegated to the ranks of the markets of underdeveloped countries.