(Adds table, details on short net yen contracts) NEW YORK, Sept 11 (Reuters) - Speculators raised bullish bets on the U.S. dollar for the first time in four weeks, according to Reuters calculations and data from the Commodity Futures Trading Commission released on Friday.
The value of the dollar's net long position rose to $22.07 billion in the week ended Sept. 8, from $21.61 billion the previous week. That said, this was the third straight week U.S. dollar longs have come in below $30 billion.
To be long a currency is to make a bet it will rise, while being short is a bet its value will decline.
The dollar has gained some traction after several Federal Reserve officials such as Federal Reserve Vice Chair Stanley Fischer and Atlanta Fed President Dennis Lockhart, did not rule out an interest rate hike next week despite the market's decline during the last week of August.
The Fed officials gave their comments on the sidelines of a global central bankers' conference in Jackson Hole, Wyoming.
In August, the dollar index was down 1.6 percent. For September, however, the dollar's losses were down to 0.7 percent.
Investors also continued to pare back their net short yen positions to their smallest in about four months. Net short yen contracts fell to 6,662 from 15,555 previously.
In the past few weeks, investors have been reversing carry trades or bets in more lucrative assets, funded by the low-yielding euro and yen, resulting in a rally in both currencies.
The Reuters calculation for the aggregate U.S. dollar position is derived from net positions of International Monetary Market speculators in the yen, euro, British pound, Swiss franc and Canadian and Australian dollars.
Japanese Yen (Contracts of 12,500,000 yen) 08 Sep 2015 Prior week week Long 63,121 68,023 Short 69,783 83,578 Net -6,662 -15,555 EURO (Contracts of 125,000 euros) 08 Sep 2015 Prior week week Long 75,715 74,910 Short 156,956 142,767 Net -81,241 -67,857 POUND STERLING (Contracts of 62,500 pounds sterling) 08 Sep 2015 Prior week week Long 43,509 47,801 Short 61,147 59,040 Net -17,638 -11,239 SWISS FRANC (Contracts of 125,000 Swiss francs) 08 Sep 2015 Prior week week Long 5,585 5,442 Short 12,481 13,945 Net -6,896 -8,503 CANADIAN DOLLAR (Contracts of 100,000 Canadian dollars) 08 Sep 2015 Prior week week Long 29,506 28,964 Short 78,146 84,083 Net -48,640 -55,119 AUSTRALIAN DOLLAR (Contracts of 100,000 Aussie dollars) 08 Sep 2015 Prior week week Long 50,072 50,928 Short 103,388 106,660 Net -53,316 -55,732 MEXICAN PESO (Contracts of 500,000 pesos) 08 Sep 2015 Prior week week Long 22,880 21,353 Short 93,831 98,290 Net -70,951 -76,937 NEW ZEALAND DOLLAR (Contracts of 100,000 New Zealand dollars) 08 Sep 2015 Prior week week Long 11,677 13,543 Short 23,497 21,822 Net -11,820 -8,279 (Reporting by Gertrude Chavez-Dreyfuss; Editing by Diane Craft and Grant McCool)