The culprit seems to be a strengthening U.S. dollar, which earlier caused the yen to fall through the key ¥100 level against the dollar for the first time since April 2009, and sent the euro tumbling against the dollar as well.
Meanwhile, stocks are selling off.
Seabreeze Partners fund manager Doug Kass is tweeting "vague rumors" that WSJ reporter Jon Hilsenrath – nicknamed "Fedwire" for his association with the Federal Reserve – is working on an article about Federal Reserve tapering.
However, it's unclear whether Doug Kass tweets about rumored Hilsenrath articles are really enough to move markets these days.
Thinkorswim