In an unprecedented move, the Fed and the International Swaps and Derivatives Association allowed derivatives trading today, on a Sunday, to "reduce risk associated with a potential Lehman . . . bankruptcy."

Lehman holds $ 800 billion in derivatives.

As the very even-keeled and level-headed chief executive of Pimco, the world's biggest bond fund, said:

Another great depression. Perhaps even a world-wide depression.

To see why derivatives are the key to the financial crisis in the U.S. and the world, and why the Fed allowed derivatives trading today, read this.