The "shadow markets" in this article reminded me of the "shadow systems" we often run into in the business intelligence space. Except instead of rouge, hidden, and prone to error spreadsheets it's rouge markets. Because the logic is effecively hidden dishonest individuals can use their shadow spreadsheets to massage their numbers into an up and to the right shape. The same potential for abuse and accident exists in shadow markets but with the global economy on the line. Terrifying thought!