Specs lift long U.S. dollar bets this week -CFTC, Reuters data

(Adds details, comment, table, byline) By Gertrude Chavez-Dreyfuss Feb 24 (Reuters) - Speculators increased bullish bets on the U.S. dollar for the first time in seven weeks, according to Commodity Futures Trading Commission data released on Friday and calculations by Reuters.

The value of the dollar's net long position totaled $15.02 billion in the week ended Feb. 21, up from $14.99 billion the previous week.

Despite the rise in the dollar's net long positioning, the greenback remains an underperformer so far this year, down about 1.1 percent, after gains of 3.6 percent in full-year 2016.

Analysts said investors may have gotten ahead of themselves, buying the dollar in the aftermath of the election as U.S. president of Donald Trump, who promised tax reform and infrastructure spending to boost the economy.

Roughly two months after Trump's election, the market remained in the dark on the new government's fiscal measures and tax plan.

"We think the dollar should be trading higher, but there's no question that investors need more convincing," said Kathy Lien, managing director of FX strategy at BK Asset Management in New York.

She also added that investors were just not convinced that a U.S. interest rate hike will happen next month.

CFTC data also showed net shorts of 50,162 Japanese yen contracts, the lowest in more than two months.

The yen has gained more than 4 percent so far this year, capitalizing on the U.S. dollar's struggles.

Trump is expected to give a major speech next week before a joint session of Congress. Lien said any policy announcement could dictate how dollar/yen moves next week.

"The currency pair came under heavy selling pressure in previous days and looks vulnerable to a deeper correction," she added.

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) $5.611 billion 21 Feb 2017 Prior week week Long 29,954 27,701 Short 80,116 78,985 Net -50,162 -51,284 EURO (Contracts of 125,000 euros) $6.183 billion 21 Feb 2017 Prior week week Long 130,981 125,333 Short 189,232 172,097 Net -58,251 -46,764 POUND STERLING (Contracts of 62,500 pounds sterling) $5.106 billion 21 Feb 2017 Prior week week Long 38,253 39,039 Short 104,605 104,567 Net -66,352 -65,528 SWISS FRANC (Contracts of 125,000 Swiss francs) $1.428 billion 21 Feb 2017 Prior week week Long 6,945 6,608 Short 15,881 18,092 Net -8,936 -11,484 CANADIAN DOLLAR (Contracts of 100,000 Canadian dollars) $-1.479 billion 21 Feb 2017 Prior week week Long 58,780 53,152 Short 34,196 33,812 Net 24,584 19,340 AUSTRALIAN DOLLAR (Contracts of 100,000 Aussie dollars) $-1.855 billion 21 Feb 2017 Prior week week Long 88,768 79,313 Short 55,246 55,095 Net 33,522 24,218 MEXICAN PESO (Contracts of 500,000 pesos) $1.486 billion 21 Feb 2017 Prior week week Long 35,125 30,271 Short 91,606 90,484 Net -56,481 -60,213 NEW ZEALAND DOLLAR (Contracts of 100,000 New Zealand dollars) $-0.206 billion 21 Feb 2017 Prior week week Long 35,252 36,565 Short 32,094 33,689 Net 3,158 2,876 (Reporting by Gertrude Chavez-Dreyfuss; Editing by James Dalgleish)