Learn how the US Dollar Index works, what drives DXY movements, how Fed policy, interest-rate differentials and risk sentiment affect the dollar, and how traders can approach it.
US Dollar Index: The Value Compass of Global FX Markets
As the world’s core reserve currency, movements in the US dollar exchange rate continue to affect cross-border trade settlement, international capital flows and forex trading decisions. In everyday financial-market language, references to the “rise and fall of the dollar” usually do not point to the exchange-rate movement of a single currency pair, but to the performance of theUS Dollar Index(DXY) as a composite indicator. Understanding the index’s calculation logic, driving mechanisms and volatility characteristics is a fundamental step in assessing the medium- to long-term direction of the FX market.
The dollar’s position in the global monetary system is supported by several indicators. According to statistics from the Society for Worldwide Interbank Financial Telecommunication (SWIFT), the US dollar’s share of global payments rose to 50.49% in December 2025, reaching a high level since 2023; over the same period, the renminbi accounted for around 2.73%, the euro for around 21.9%, and sterling for around 6.73%. (Source: SWIFT, Monthly RMB Tracker, published: 2026-01) This set of data shows that although the topic of “de-dollarisation” continues to gain attention, the dollar’s dominant position in the international payment system remains difficult to replace in the short to medium term.
The Starting Point of the US Dollar Index and the Evolution of Its Currency Basket
The US Dollar Index is a composite indicator formed by calculating the weighted exchange rates of a basket of developed-economy currencies. Its core function is to measure the overall strength or weakness of the dollar relative to that currency basket. The index was first compiled in March 1973, initially based on exchange-rate data for 10 currencies, with the index base set at 100 points at that time. This base level became the benchmark anchor for subsequently measuring changes in the dollar’s value.
The index reading has an intuitive relative meaning:
An index reading of 95 indicates that, compared with the benchmark level in March 1973, the dollar’s composite value against the currency basket has fallen by around 5%;
An index reading of 105 indicates that the dollar has appreciated by around 5% relative to the benchmark.
With the establishment of the European Union and the launch of the euro (EUR), the euro replaced five European currencies in the original basket: the Deutsche mark, French franc, Italian lira, Dutch guilder and Belgian franc. This simplified the US Dollar Index basket to six currencies and ultimately formed the current calculation framework. In the current basket, the euro has the highest weighting, at around 57.6%, followed by the Japanese yen at around 13.6%, sterling at around 11.9%, the Canadian dollar at around 9.1%, the Swedish krona at around 4.2% and the Swiss franc at around 3.6%. (Source: Trading Economics, US Dollar Index)
Core Variables Driving Movements in the US Dollar Index
The rise and fall of the US Dollar Index is not the result of a single factor, but is jointly driven by multiple macroeconomic and market variables. To make several easily confused related concepts easier to distinguish, the following table compares their meanings, directional impact and time-effect characteristics.
| Core Factor | Essential Meaning | Directional Impact on the US Dollar Index | Time Effect |
|---|---|---|---|
| Federal Reserve monetary policy | Interest-rate adjustments and balance-sheet operations, determining dollar yields and liquidity supply | Rate increases and quantitative tightening are supportive; rate cuts and quantitative easing are negative | Medium- to long-term underlying engine |
| Differences in economic fundamentals | Relative strength between the United States and non-US economies in growth, employment and business conditions | Supportive when the US is strong and non-US economies are weak; negative in the opposite case | Medium- to long-term anchoring basis |
| Global risk-aversion sentiment | Temporary demand for safe-haven assets during risk events | Supportive when risk aversion rises, driving short-term surges | Short-term shock variable |
| Cross-market interest-rate differentials | Yield differences between US Treasuries and non-US government bonds | Widening differentials are supportive; narrowing differentials are negative | Direct transmission link for capital flows |
Federal Reserve Monetary Policy: The Medium- to Long-Term Underlying Engine
As the issuer of the dollar and the core policymaker of US monetary policy, the Federal Reserve’s policy toolkit directly determines the dollar’s yield level and the supply of market liquidity. Among these tools, interest-rate adjustments, including rate increases and rate cuts, and balance-sheet operations, including quantitative tighteningQTand quantitative easingQE, are the most important. In general, rate increases and balance-sheet reduction support the US Dollar Index by improving the attractiveness of dollar assets and tightening liquidity; rate cuts and quantitative easing put pressure on the index by lowering yields and releasing liquidity.
Differences in Economic Fundamentals: The Anchor of Relative Value
The essence of the US Dollar Index is “relative value”. The comparison of economic strength between the United States and component economies such as the eurozone and Japan — including gross domestic product growth, employment conditions and purchasing managers’ indices — directly affects the market’s assessment of the attractiveness of the respective currencies. This forms a core anchoring basis for analysing the medium- to long-term direction of the US Dollar Index. Hu Jie, professor at Shanghai Advanced Institute of Finance, Shanghai Jiao Tong University, and a former senior economist at the Federal Reserve, has pointed out that exchange-rate movements are usually driven by three main factors: interest-rate differentials, trade differentials and differences in national strength.
“When uncertainty originates from within the United States, the dollar’s safe-haven halo often weakens.”
Global Risk-Aversion Sentiment: A Short-Term Shock Variable
Thanks to its status as a core reserve currency, the US dollar has become one of the representative safe-haven assets in global financial markets. When risk events such as financial crises or geopolitical conflicts break out, risk-aversion sentiment rises, and capital often withdraws from risk assets and non-US currencies before flowing into the dollar. This tends to push the US Dollar Index sharply higher in the short term, forming a typical safe-haven rally. It should be noted that the sustainability of such rallies depends on whether safe-haven demand can continue. Once the risk event eases, the related gains may be given back relatively quickly.
Cross-Market Interest-Rate Differentials: The Transmission Link for Capital Flows
The interest-rate differential between US Treasuries and non-US government bonds, especially the differential with the eurozone, is a core guide for cross-border capital flows. When the differential widens, the yield advantage of dollar assets becomes more prominent, attracting global capital inflows and creating upward momentum for the US Dollar Index. A narrowing differential, by contrast, puts pressure on the index.
Recent Trajectory and Phase Characteristics of the US Dollar Index
Looking back at the trend since the beginning of this century, the US Dollar Index has alternated between range-bound and one-way trends under the shifting influence of macroeconomic cycles, geopolitical conditions and monetary policy. The following outlines several representative phases in chronological order:
From March 2022, the Federal Reserve began rapid rate increases to curb inflation, driving a strong rebound in the US Dollar Index. In September of the same year, the index once broke above 114, reaching a roughly 20-year high, while the euro at one point fell below parity against the dollar.
From 2023 to 2024, US inflation declined but core inflation remained above target. The US Dollar Index fluctuated within the 100 to 107 range, reflecting market disagreement over the path of interest rates.
In the first half of 2025, the dollar retreated from its early-year high, with the cumulative decline once becoming relatively notable, as the market reassessed changes in interest-rate differentials between the United States and other major economies.
In the first half of 2026, market pricing of Federal Reserve policy rapidly shifted from “continued rate cuts” to “renewed rate increases cannot be ruled out”. The US Dollar Index once climbed to its highest level since early 2025 and traded above 100. (Source: Trading Economics, US Dollar Index, published: 2026-06)
The underlying variable behind this round of dollar strength is the market’s reassessment of the Federal Reserve’s anti-inflation constraints. After his first policy meeting, the new Federal Reserve Chair Kevin Warsh emphasised price stability and toned down the previously over-detailed forward guidance, leading the market to revise up the probability of rate increases. Kevin Warsh is the current Chair of the Federal Reserve and has long focused on price stability and monetary policy framework issues. This combination means that the US Dollar Index has become significantly more sensitive in the short term to inflation, employment and wage data.
Thresholds and Participation Routes for US Dollar Index Trading
US Dollar Index futures and options contracts on the Intercontinental Exchange (ICE) and the Chicago Mercantile Exchange (CME) usually involve relatively high trading thresholds, making it difficult for some small and medium-sized investors to participate directly. Lower-threshold instruments such as contracts for difference have broadened access to some extent, but the choice of instrument must be aligned with one’s own risk tolerance. The general steps for participating in US Dollar Index trading are as follows:
Apply for a free demo account and spend one to two weeks becoming familiar with forex quote codes and contract rules;
Use demo trading to become familiar with the trading software, then open a live account and test the market with a small amount of capital;
Understand the auxiliary trading tools provided by the broker and assess its information services and risk-warning capabilities.
In terms of participant structure, the US Dollar Index has different value propositions for traders at different levels of experience. For beginners, its movements are directly linked to public information such as Federal Reserve interest-rate decisions, gross domestic product and inflation data, making its signals relatively clear and suitable as an observation tool for understanding macro trading logic. For experienced traders, the relationships between the US Dollar Index and non-US currencies, gold and crude oil are not fixed. Under complex conditions such as geopolitical conflicts and policy divergence among central banks, structural opportunities may instead emerge.
Questions Related to the US Dollar Index
Are the US dollar and the US Dollar Index the same concept?
No. The US dollar is a single sovereign currency, and its value is reflected through the exchange rates of specific currency pairs. The US Dollar Index is a composite indicator calculated by weighting a basket of developed-economy currencies. It measures the overall strength or weakness of the dollar relative to that basket, rather than the dollar’s exchange rate against a single currency.
Which currency has the highest weighting in the US Dollar Index basket?
It is the euro, with a weighting of around 57.6%. It is followed by the Japanese yen, sterling, the Canadian dollar, the Swedish krona and the Swiss franc. Therefore, movements in EUR/USD have the most significant impact on the US Dollar Index.
How were the benchmark level and benchmark date of the US Dollar Index set?
The US Dollar Index was compiled in March 1973, using that point in time as the benchmark and setting the base value at 100 points. Since then, an index level above 100 has indicated that the dollar has appreciated relative to the benchmark, while a level below 100 has indicated depreciation relative to the benchmark.
What has the historical fluctuation range of the US Dollar Index roughly looked like?
Since the beginning of this century, the US Dollar Index has seen considerable fluctuations under the influence of multiple factors. In September 2022, it once broke above 114, reaching a roughly 20-year high; earlier, during periods of loose monetary policy, it had also traded at lower levels. In recent years, its fluctuation range has generally narrowed, mostly moving between 90 and 115.
Why has the US Dollar Index become a “barometer” for global markets?
Because the US dollar is the world’s core reserve currency and a major settlement currency, its relative value is directly linked to cross-border capital flows, commodity pricing and safe-haven fund movements. The US Dollar Index centrally reflects macro variables such as Federal Reserve policy, differences in economic fundamentals and interest-rate differentials, and is therefore widely used as a comprehensive reference for observing global liquidity and risk appetite.
