NEW YORK, Oct 23 (Reuters) - Currency speculators increased bets against the U.S. dollar in the latest week, according to Commodity Futures Trading Commission data released on Friday. The value of the dollar's net short position rose to $18.65 billion in the week ending Oct 20 from a $17.99 billion net short the prior week. The increase in net short dollars was driven mainly by the sharp decline in bearish trades on sterling. The net short position on sterling fell to 43,318 contracts in the latest week from a record high at 65,346 previously. 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.

JAPANESE YEN (Contracts of 12,500,000 yen)

10/20/09 week 10/13/09 week

Long 49,401 49,817

Short 18,216 16,478

Net 31,185 33,339

EURO (Contracts of 125,000 euros)

10/20/09 week 10/13/09 week

Long 77,829 79,762

Short 41,796 36,395

Net 36,033 43,367

POUND STERLING (Contracts of 62,500 pounds sterling)

10/20/09 week 10/13/09 week

Long 15,644 9,898

Short 58,962 75,244

Net -43,318 -65,346

SWISS FRANC (Contracts of 125,000 Swiss francs)

10/20/09 week 10/13/09 week

Long 30,017 27,537

Short 6,164 5,258

Net 23,853 22,279

CANADIAN DOLLAR (Contracts of 100,000 Canadian dollars)

10/20/09 week 10/13/09 week

Long 52,689 50,739

Short 9,152 6,543

Net 43,537 44,196

AUSTRALIAN DOLLAR (Contracts of 100,000 Aussie dollars)

10/20/09 week 10/13/09 week

Long 62,429 59,930

Short 8,439 7,283

Net 53,990 52,647

MEXICAN PESO (Contracts of 500,000 pesos)

10/20/09 week 10/13/09 week

Long 63,913 32,215

Short 8,729 24,266

Net 55,184 7,949

NEW ZEALAND DOLLAR (Contracts of 100,000 New Zealand dollars)

10/20/09 week 10/13/09 week

Long 19,531 19,432

Short 2,373 1,802

Net 17,158 17,630

(Reporting by Gertrude Chavez-Dreyfuss; Editing by DanGrebler)

U.S.