The yen and Swiss franc firmed broadly on Monday as US stocks fell on credit-related worries, prompting investors to reduce exposure to risky assets and unwind trades funded by the Japanese and Swiss currencies' low rates.
The yen approached eight-year highs against the dollar while the Swiss franc rose to roughly two-year peaks against the euro and was within striking distance of its record high against the greenback.
The dollar, meanwhile, steadied against the euro after Europe's top monetary officials expressed concern about excessive movements in currency exchange rates. In the stock market, US equities fell, led by financial shares such as Ambac Financial, down 23 percent and Bear Stearns, which fell 11 percent.
"Risk aversion is definitely a function of the market, with North American equities trading heavily today," said Shane Enright, a currency strategist at CIBC World Markets in Toronto.
"The carry currencies are struggling - the New Zealand and Australian dollars. And the yen is usually a beneficiary of higher risk aversion and it has continued to strengthen," he added.
The greenback hit a session low of 101.57 yen, just shy of Friday's eight-year low around 101.40 yen, before edging back in late afternoon to 101.75 yen, down 0.9 percent on the day. Traders said they were keeping an eye on the key 100-yen level against the dollar last seen more than a decade ago.
The euro fell to one-week lows against the yen to 155.96, before trading back up to 156.10, still down 1 percent from late on Friday. The high-yielding Australian and New Zealand dollars fell 2.1 percent and more than 1 percent against the yen, respectively.
The Swiss franc, meanwhile, climbed against the euro, which fell to 1.5621, the lowest since July 2006. The currency pair last traded at 1.5644, down 0.6 percent. The dollar dropped 0.6 percent against the Swiss franc to 1.0192. On Friday, the greenback hit a record low at 1.0136 Swiss francs.
The dollar, on the other hand, was up slightly against the euro, which traded at $1.5347. The euro had hit a record peak against the dollar Friday around $1.5459, following a report showing the US economy unexpectedly shed 63,000 jobs last month. The euro's surge was also halted on Monday, after European Central Bank President Jean-Claude Trichet said the central bank was concerned about "excessive exchange rate moves."