A major central bank decides to remove its currency peg. An investment bank’s traders scramble to take cover. The foreign exchange spot trading book is tens of millions of dollars in the red. Grey-faced executives are slamming their fists on the table.

Then it is discovered that there is a silver lining. The value of positions connected to volatility in the foreign exchange market has soared, more than offsetting the losses on the spot trading book. The markets business, much to the delight of the previously distressed executives, has its head above water.