The euro slid to a four-week low versus the dollar as Italian bond yields climbed to euro-era records after a firm raised the deposits it demands for clearing the nation’s securities, intensifying Europe’s debt crisis. The shared currency fell to a two-week low versus the yen on concern Italy will join Greece in struggling to form a new regime strong enough to implement austerity measures. LCH Clearnet SA announced the changes to its margin requirements on Italian government-debt on its website.

The 17-nation currency remained lower versus the dollar as Greek Prime Minister George Papandreou said in Athens his country’s two biggest political parties reached agreement on the creation of a national unity government after three days of talks. Papandreou will step down. He didn’t disclose the name of the new prime minister.

The dollar rose as U.S. 10-year note yields declined the most in a week as demand for refuge surged. The Dollar Index, which IntercontinentalExchange Inc. uses to track the greenback against the currencies of six major U.S. trading partners climbed 1.3 percent to 77.630.

The yen strengthened against most of its major peers as traders sought a haven. The Japanese currency and yen- denominated bonds were the most-sought assets today, according to Bank of New York Mellon Corp. The yen tends to gain because Japan’s export-reliant economy doesn’t need foreign capital to balance current accounts -- the broadest measure of trade while the greenback tends to strengthen during periods of financial stress due to its status as the world’s reserve currency.