On Monday, I brutalized my muscles in my first Krav Maga class. Afterwards, I got drinks with one of the people from the class who turned out to have a really interesting finance job. He is a lawyer who writes contracts for derivatives.
In my naivete, I said something to the effect of, "That must be exhausting writing and reviewing all those contracts so quickly." His response made me think about something in derivatives markets I had never thought of before. As he explained it, his job was to draft template contracts in advance of trading. He said that a minor oversight in the wording could mean thousands of trades that have nothing to do with fundamentals.
So in addition to "animal spirits" affecting the financial markets seemingly at random, the legal frameworks under-girding the financial market itself pushes traders in various directions. So much for fundamentals.