The MF Lesson: U.S. Is Exposed to EU

You can understand why Wall Street wants to play down the threats from Europe. Its profits depend on the marketâ??s confidence in the products it sells â?? and on the belief that the firms that sell those products will be around tomorrow.

But MF Global provides two lessons. The first is that our financial institutions are not impervious to Euro-shocks. The second is that when those problems reach our shores, they usually ride in on a wave of derivatives.