Jan 3 (Reuters) - Speculators cut their net long U.S. dollar positions in the latest week, according to calculations by Reuters and U.S. Commodity Futures Trading Commission data released on Monday. The value of the net long dollar fell to $19.15 billion in the week ended Dec. 28, compared with a net long of $19.71 billion the previous week. The Reuters calculation for the aggregate U.S. dollar position is derived from net positions in the yen, euro, British pound, Swiss franc, and Canadian and Australian dollars. In a wider measure of dollar positioning that includes net contracts on the New Zealand dollar, Mexican peso, Brazilian real and Russian rouble. The U.S. dollar posted a net long position of $19.75 billion, compared with a net long of $20.06 billion a week earlier. Japanese Yen (Contracts of 12,500,000 yen) Net dollar long by $5.782 billion 28 Dec 2021 week Prior week Long 32,475 22,191 Short 85,577 74,477 Net -53,102 -52,286 EURO (Contracts of 125,000 euros) Net dollar long by $0.938 billion 28 Dec 2021 week Prior week Long 198,617 196,595 Short 205,251 206,757 Net -6,634 -10,162 POUND STERLING (Contracts of 62,500 pounds sterling) Net dollar long by $4.258 billion 28 Dec 2021 week Prior week Long 23,093 20,824 Short 73,812 78,510 Net -50,719 -57,686 SWISS FRANC (Contracts of 125,000 Swiss francs) Net dollar long by $1.46 billion 28 Dec 2021 week Prior week Long 1,043 2,460 Short 11,761 11,687 Net -10,718 -9,227 CANADIAN DOLLAR (Contracts of 100,000 Canadian dollars) Net dollar long by $0.806 billion 28 Dec 2021 week Prior week Long 42,528 45,925 Short 52,862 55,802 Net -10,334 -9,877 AUSTRALIAN DOLLAR (Contracts of 100,000 Aussie dollars) Net dollar long by $5.908 billion 28 Dec 2021 week Prior week Long 16,885 22,958 Short 98,626 103,312 Net -81,741 -80,354 MEXICAN PESO (Contracts of 500,000 pesos) Net dollar long by $-0.218 billion 28 Dec 2021 week Prior week Long 33,561 30,021 Short 42,569 34,813 Net -9,008 -4,792 NEW ZEALAND DOLLAR (Contracts of 100,000 New Zealand dollars) Net dollar long by $0.574 billion 28 Dec 2021 week Prior week Long 11,231 11,050 Short 19,652 17,186 Net -8,421 -6,136