Currency speculators cut their bets in favour of the US dollar in the latest week while they boosted short yen positions to a more than five-year high, according to data from the Commodity Futures Trading Commission released on Friday. The value of the dollar's net long position fell to $8.01 billion in the week ended November 27 from a long position of $11.2 billion the previous week.

Bets against the yen rose to 79,466 contracts, the highest since the beginning of May, 2007 when short positions reached 118,782 contracts, according to Reuters data. Short yen positions stood at 51,389 contracts in the previous week. The yen has weakened significantly in recent sessions as speculation grew that a likely change in Japan's government would lead to aggressive monetary easing.

The yen hit a near eight-month low against the dollar last week and a seven-month low against the euro on Friday. 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