Just as the Dow Jones Industrial Average provides a general indication of the value of the US stock market, the US Dollar Index (USDX®) provides a general indication of the international value of the US Dollar. Similar in many respects to the Federals Reserve Board's trade-weighted index, the USDX does this by averaging the exchange rates between the US Dollar and six major world currencies.
These 17 countries (12 countries of the Euro zone plus the five other nations whose currencies are represented in the USDX) constitute the bulk of international trade with the United States, and have well-developed foreign exchange markets with rates freely determined by market participants. In addition, many currencies not included in the USDX move in close correlation with those that are included. The USDX is computed 24 hours a day, seven days a week.
Currencies and weights used in the calculation of the USDX are the same as those used in the Federal Reserve Boards trade-weighted US Dollar Index.
Since the USDX is based only on indications of foreign exchange rate values, it may occasionally differ from a value calculated using other data sources.
The USDX is calculated as a geometric weighted average of the change in six foreign currency exchange rates against the US Dollar relative to March 1973. The USDX measures the dollar's general value relative to a base of 100.00. A quote of 105.50 means the dollar's value has risen 5.50% since this base period.
March 1973 was chosen as a base period because it represents a significant milestone in foreign exchange history when the world's major trading nations allowed their currencies to float freely against each other. This agreement was reached at the Smithsonian Institution in Washington, DC and was a victory for free market theorists. The Smithsonian agreement replaced the unsuccessful fixed rate regime established approximately 25 years earlier at Bretton Woods, New Hampshire.
The current level of the USDX reflects the average value of the dollar relative to this
1973 base period. Since that time, the Dollar Index has traded as high as the mid-160's and as low as the high-70's. Volatility of this instrument is comparable in range and variability to a broad-based, multi-capitalization stock index future.
