Speculators ditched bets against the dollar in the latest week and were long the U.S. currency for the first time since May, according to Commodity
Futures Trading Commission data released on Monday.

The value of the dollar's net long position was around $700 million in the week ending Dec. 22, up from a net short position of $1.98 billion the prior week, according to Reuters calculations.

The latest week marked the first time since early May that speculators took a long position on the dollar, which is a bet that the currency will rise in value. It also ended 32 straight weeks of short dollar positions, according to CFTC data.

The shift comes in a month that has seen the dollar rally sharply against major currencies after spending most of 2009 under steady pressure. At the height of the dollar selling on spot markets, the value of speculators' net short position rose as high as $20.7 billion, according to Reuters calculations.

In the latest week, speculators ditched bets in favor of the yen and Swiss franc to go short both currencies and trimmed bets in favor of the Canadian and Australian dollars.

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