ZURICH - The euro slumped to a four-year low on Monday, as investors dumped the single currency on sovereign debt worries and on fears that recent belt-tightening measures would hurt a recovery in the euro zone area. The euro extended its losses after falling below $1.2300, where option barriers were said to lurk, and fell as far as $1.2234 on trading platform EBS, its lowest since April 2006. It has dropped more than 7 per cent against the dollar this month, and is about 14 percent lower for the year, making it the worst-performing major currency. The euro's next major trough on charts lies at $1.1640, a low hit in November 2005. "People have no idea what it will take to get out of this situation as they have seen euro plunge despite a massive rescue package," said Minoru Shioiri, the chief manager of FX trading at Mitsubishi UFJ Morgan Stanley Securities. "There are very big concerns about the euro zone." There are worries about the health of European banks which have exposure to sovereign bonds in Greece and some other euro zone nations with high fiscal deficits, traders said. "Risk aversion stemming from the euro zone fiscal crisis will likely keep investors shifting their funds into safer assets such as the dollar, the yen, US Treasuries and gold," said a trader at a Japanese bank. On Friday, the euro plunged after European Central Bank policymaker Axel Weber said it was important not to underestimate lingering dangers to financial stability. German Chancellor Angela Merkel said on the Sunday the $1 trillion rescue plan stitched together by the European Union and the International Monetary Fund only bought time to sort out the yawning gap between the euro zone's strongest and weakest economies.