How the Dollar Impacts Commodity Prices

The General Rules Might Be Changing

a man checking stock market
••• Kidsada Manchinda / Getty Images

There's normally an inverse relationship between the value of the dollar and commodities prices. Historically, the prices of commodities have tended to drop when the dollar strengthens against other major currencies, and when the value of the dollar weakens against other major currencies, the prices of commodities generally move higher. This is a general rule, and the correlation isn't perfect, but there's often a significant inverse relationship over time.

If you look at a chart of the Commodity Research Bureau (CRB) Index, it tracks a diverse group of commodities prices against a chart of the dollar index. This represents the strength or weakness of the U.S. currency against other foreign exchange instruments.

Key Takeaways

  • Normally, there is an inverse relationship between the value of the dollar and commodities prices.
  • The value of the dollar influences commodities prices mainly because the dollar is the benchmark pricing mechanism for most commodities.
  • According to Citi Research, the correlation between the dollar and commodities prices has recently become less significant.
  • Keep a close eye on the value of the dollar and its correlation with commodities by watching the price quotes of the U.S. Dollar Index.

Why the Movement? 

The primary reason the value of the dollar influences commodities prices is that the dollar is the benchmark pricing mechanism for most commodities. U.S. currency is the reserve currency of the world. The dollar tends to be the most stable foreign exchange instrument, so most other nations hold dollars as reserve assets.

When it comes to international trade for raw materials, the dollar is the exchange mechanism in many if not most cases. When the value of the dollar drops, it costs more dollars to buy commodities. At the same time, it costs a lesser amount of other currencies when the dollar is moving lower.

Commodities Are Global Assets

Another reason for the influence of the dollar is that commodities are global assets. They trade all over the world. Foreign buyers purchase U.S. commodities such as corn, soybeans, wheat, and oil with dollars. When the value of the dollar drops, they have more buying power, because it requires lower amounts of their currencies to purchase each dollar. Classic economics teaches that demand typically increases as prices drop.

The Dollar Is the Benchmark Because It's Stable

Commodities don't trade in a vacuum. Commodity production is often a localized affair. The majority of corn and soybean production in the world comes from the fertile lands of the U.S. The mineral-rich soil of Chile yields the largest output of copper on earth, and half the world’s oil reserves are located in the Middle East. The largest producers of cocoa beans are in Africa, in the Ivory Coast and Ghana regions.

As you can see, commodity production depends on climate and geology in specific locations, but the people and companies that want these important raw materials are located all over the globe.

The vast majority of these materials use the dollar as a pricing mechanism for global trade because of the United States' strong, stable economy. When the dollar strengthens, commodities become more expensive in other, nondollar currencies. This effect tends to have a negative influence on demand, and as you would expect, when the dollar weakens, commodities prices in other currencies drop lower, which increases demand.

The Effect on Commodities 

Each commodity has idiosyncratic characteristics, but the value of the dollar has historically had a direct influence on the prices of all commodities. When the dollar began to strengthen in May 2014, the U.S. dollar index traded to 78.93 on the active month futures contract. In early March 2016, that dollar index was trading around the 97 level; the dollar had appreciated by around 23% in less than two years. 

Many commodities prices moved lower over that period—a perfect example of the inverse relationship between the value of the dollar and commodities prices. Historical relationships can serve as a guide, because history tends to repeat itself, but there are times when major divergences occur, so it's possible that commodities prices and the dollar can occasionally move in the same direction.  

Is Change in the Air? 

Citi Research reported in 2017 that the correlation between the dollar and commodities prices became less significant after the dollar index was trading at about 97 just a year before. Specifically, commodities were strong in the latter half of 2016, even as the U.S. dollar gained against other currencies. It was the most significant variation in the correlation a decade. Citi had indicated that it thought this state of affairs might last for a while. In June of 2019, the U.S. dollar index was at about 97 again, after fluctuating lower during 2018, while many commodities were down for the year.

Monitoring the Dollar 

One of the best ways to hedge against change, and to keep a close eye on the value of the dollar and its correlation with commodities, is to watch the price quotes of the U.S. Dollar Index (ticker: DXY).

This index is traded on the ICE Futures Exchange. This futures contract is an index that values the dollar against a group of other major currencies around the world, including the euro, the yen, and the British pound. The price of the index is traded like any other futures contract, and it moves up and down during trading hours.

Commodities prices don’t necessarily tick higher for every tick lower in the Dollar Index, but there's often been a strong inverse relationship over the long haul. Individual commodities have fundamental supply-and-demand characteristics, so they move one way or another at times, regardless of the direction of U.S. currency. Risk aversion plays a part, particularly in recent events. Keep your eye on the situation, and don't take previous trends for granted.

Frequently Asked Questions (FAQs)

How do you trade DXY?

There are many ways to trade the dollar index. The easiest way for stock traders to trade DXY is through ETFs. UUP, for example, is an ETF that provides bullish exposure to the dollar index. When DXY goes up, UUP goes up, and vice versa. UDN is essentially the opposite—an ETF that provides bearish exposure. Futures traders can trade DXY through USDX. Forex traders typically trade pairings rather than a single currency's index, so they take a bullish or bearish position on the dollar relative to another currency.

Where can you get historical commodities prices?

The Federal Reserve Bank of St. Louis maintains a database with historical commodities prices alongside a lot of other economic data. It's a great place to start researching any questions you have about economic trends. Commodity indexes are also closely tracked by traders, so charting software designed for traders will give you access to commodity price history alongside technical indicators and other charting tools.