The U.S. bond market rallied this week on renewed safe-haven bids as well as relief buying in reaction to the release of minutes from the Federal Reserve's March 18-19 policy meeting.
The intense appetite for bonds spread into this week's auction of $64 billion worth of longer-term debt, which raised $13.5 billion in new cash for the federal government.
An MSCI benchmark of global equities fell to a two-week low, spurred by a broad risk-averse tenor among investors that led to selloffs in higher-yielding currencies and emerging market assets.
"Today's decline is what we've been seeing all week. The weakness in the biotech and momentum names is getting investors worried about where the market is headed in the near-term, eventually triggering a selloff in everything," said Robert Pavlik, chief market strategist at Banyan Partners in New York.
"Our long-term outlook on the market hasn't changed because if you understand why the market is selling off, you know it's not rational, that it doesn't make sense," he added.
MSCI's all-country world equity index fell to lows last seen in late March and was last trading down 1.0 percent.
The dollar index, which measures the greenback against six major currencies, rose 0.13 percent, and the dollar edged higher against the yen, also up 0.13 percent. The euro fell slightly after being ahead a tad against the dollar most of the session.
"Bad news for the world is good news for the dollar," said Steven Englander, managing director and global head of G10 FX strategy at CitiFX in New York. "Once fears about the equity market intensified, they picked up a more conventional type of mode to buy the dollar."