All of a sudden, the fundamentals aren't looking as strong.
First it was Apple's $5 billion revenue miss, hints of which lopped 30 per cent from its stock over three months. Now it's a closely watched gauge of US factory activity, which dropped to a two-year low and missed every estimate in a Bloomberg survey.
What's going on? Over and over in the fourth quarter, as the S&P 500 plunged 19.8 per cent to the brink of a bear market, investors heard the same refrain: don't panic, the economy, and corporate earnings, look strong.
In the last 24 hours, confidence in those assurances has taken a hit. The Dow Jones Industrial Average fell more than 600 points, or 2.6 per cent, Thursday morning, while losses in the Nasdaq 100 spiralled toward 3 per cent.
"The market is the wisdom of all investors - it was discounting this type of news-flow with the sharp and violent sell-off we got in December," Alec Young, managing director of global markets research at FTSE Russell, said in a phone interview. "When it makes a big move, up or down, it's telling you positive or negative things about future developments. The extreme move down was telling you we'd get this type of news-flow."