What Are Indices in Forex? A Complete Guide to Currency Indices in 2025

When traders discuss indices in forex, they're referring to measurements that track currency strength relative to a basket of other currencies. Unlike stock market indices that track company shares, forex indices measure the relative value of currencies—with the most famous being the U.S. Dollar Index (DXY), which compares the dollar against six major world currencies. Understanding forex indices is crucial for anyone trading currencies, commodities, or global markets, as currency movements ripple through every asset class. In 2025, the concept of indices has evolved beyond traditional forex into cryptocurrency markets, where innovative products like the TM Global 100 apply systematic index strategies with active risk management. This comprehensive guide will explain what indices mean in forex trading, how they're calculated, why they matter for your investments, and how modern index innovations are transforming both currency and crypto markets.
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What Are Indices in Forex? The Basic Definition
In forex (foreign exchange) markets, an index measures the strength of one currency against a basket of other currencies. Rather than tracking just one currency pair (like EUR/USD), a forex index provides a broader view of how a currency performs against multiple trading partners simultaneously.
Think of it this way: if you only look at EUR/USD, you see how the dollar performs against the euro. But what about the dollar against the yen, pound, franc, and other currencies? A forex index answers this question by creating a weighted average that captures overall currency strength.
Key characteristics of forex indices:
- Basket composition: A selected group of currencies to compare against
- Weighting methodology: How much influence each currency has in the calculation
- Base period: A starting point set to 100, with movements measured as percentage changes
- Real-time calculation: Updated continuously during trading hours
Forex indices provide currency traders, international businesses, and investors with quick snapshots of currency momentum and trends that would be difficult to discern by watching dozens of individual pairs.
The U.S. Dollar Index (DXY): The Most Important Forex Index
The U.S. Dollar Index (DXY) stands as the most widely watched forex index globally. Created in 1973 when major currencies began floating freely against the dollar, the DXY measures the dollar's strength against a basket of six major currencies.
DXY Composition and Weights
The Dollar Index includes:
- Euro (EUR): 57.6% weight
- Japanese Yen (JPY): 13.6%
- British Pound (GBP): 11.9%
- Canadian Dollar (CAD): 9.1%
- Swedish Krona (SEK): 4.2%
- Swiss Franc (CHF): 3.6%
The euro's dominant 57.6% weighting means that EUR/USD movements heavily influence the DXY. When the euro weakens against the dollar, the DXY typically rises. When the euro strengthens, the DXY typically falls.
How to Read the DXY
The Dollar Index started at 100 in March 1973. Current values compare to this baseline:
- DXY at 105: The dollar is 5% stronger than the 1973 baseline
- DXY at 95: The dollar is 5% weaker than the 1973 baseline
Rising DXY: The dollar is strengthening against the basket. Falling DXY: The dollar is weakening against the basket.
The DXY has ranged from a low near 70 (2008) to highs above 120 (1980s, 2001), reflecting decades of varying dollar strength driven by interest rates, economic growth, inflation, and geopolitical events.
Other Major Forex Indices
While the DXY dominates headlines, several other currency indices track different currencies:
- Euro Index (EUR_I): Measures euro strength against U.S. Dollar (USD), Japanese Yen (JPY), British Pound (GBP), Swiss Franc (CHF). Provides eurozone perspective on currency strength, important for European traders and businesses.
- Japanese Yen Index (JPY_I): Tracks yen performance against major trading partners, heavily weighted toward U.S. Dollar (USD), Euro (EUR), British Pound (GBP), Australian Dollar (AUD). Critical for Japanese exporters and global supply chains.
- British Pound Index (GBP_I): Measures pound strength against a basket including U.S. Dollar (USD), Euro (EUR), Japanese Yen (JPY), Swiss Franc (CHF). The pound's movements gained attention during Brexit periods.
Trade-Weighted Indices
Central banks often calculate their own trade-weighted currency indices based on actual trade volumes with different countries. These
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