Currency speculators increased their bets against the US dollar in the latest week, according to data from the Commodity Futures Trading Commission released on Friday. The value of the dollar's net short position rose to $6.39 billion in the week ended December 18, from a net short position of $1.03 billion the previous week. To be short a currency is to bet it will decline in value, while being long is a view its value will rise.

The Reuters calculation for the aggregate US dollar position is derived from net positions of International Monetary Market speculators in the yen, euro, British pound, Swiss franc, Canadian and Australian dollars.

Copyright Reuters, 2012