The stock market slumped Wednesday on concerns that tighter lending standards in China will prolong an economic recovery. Disappointing earnings results from IBM Corp. and Morgan Stanley added to the market's angst.
At the same time, a spike in the dollar pushed commodity prices sharply lower, hurting stocks of energy companies and materials producers.
The Dow Jones industrial average fell 200 points, its biggest of 2010 so far. Demand for safe havens like government debt jumped, pushing yields lower in the Treasury market.
Concerns grew that China's efforts to keep its economy under control could hurt a global recovery. A top banking regulator …