The correlation between any two variables (or sets of variables) summarizes a relationship, whether or not there is any real-world connection between the two variables. The correlation coefficient will always be between -1 and +1. These two extremes are considered perfect correlations. A negative coefficient means that the two variables, or sets of variables, will move in opposite directions (if one variable increases, the other will decrease); a positive coefficient will mean that the two will move in the same direction (as one increases, the other will increase).

If we compare the US Dollar Index (USDX), an index that tracks the value of the U.S. dollar against six other major currencies, and the value of the Dow Jones Industrial Average (DJIA), Nasdaq and S&P 500 over a 20-year period, the correlation coefficient calculated for the USDX versus the DJIA, Nasdaq and S&P 500, is 0.35, 0.39 and 0.38, respectively. Note that all of the coefficients are positive, which means that as the value of the U.S. dollar increases, so do the stock indexes, but only by a certain amount. Notice also that each coefficient is below 0.4, which means that only about 35% to 40% of the stock indexes' movements are associated with the movement of the U.S. dollar.

A country's currency can become more valuable in relation to the rest of the world in two main ways: when the amount of currency units available in the world market place is reduced (for example, when the Fed increases interest rates and causes a reduction in spending), or by an increase in the demand for that particular currency. The fact that an increase in the U.S. dollar affects the value of American stocks seems natural, as U.S. dollars are needed to purchase stocks.

The value of American stocks, especially those that are included in market indexes, tend to increase along with the demand for U.S. dollars - in other words, they are positively correlated. One possible explanation for this relationship is foreign investment. As more and more investors put their money in U.S. equities, they are required to first buy U.S. dollars, which can be used to purchase American stocks, causing the indexes to increase in value.

For more insight, see Commodity Prices And Currency Movements and Using Currency Correlations To Your Advantage.

  1. How is the value of a pip determined?

    A pip in foreign exchange trading is a measure of a price movement in a currency pair. "Pip" is an acronym for price interest ... Read Full Answer >>
  2. Why would a corporation issue convertible bonds?

    A convertible bond represents a hybrid security that has bond and equity features; this type of bond allows the conversion ... Read Full Answer >>
  3. How are NDFs (non-deliverable forwards) priced

    The price of non-deliverable forward contracts, or NDFs, is commonly based on an interest rate parity formula used to calculate ... Read Full Answer >>
  4. What are the goals of covered interest arbitrage?

    The goals of covered interest arbitrage include enabling investors to trade volatile currency pairs without risk as well ... Read Full Answer >>
  5. What is the difference between a Nostro account and a regular bank account?

    The term nostro account is a bit of an umbrella term and can have different meanings for different contexts. For instance, ... Read Full Answer >>
  6. What types of companies benefit from reporting results utilizing constant currencies ...

    Any company that does a substantial amount of business in foreign countries, and is therefore subject to foreign currency ... Read Full Answer >>
Related Articles
  1. Investing Basics

    Learn How To Trade Crude Oil in 5 Steps

    Crude oil and energy markets are specialized venues. Here are five steps to take to build consistent profits.
  2. Forex Education

    The Most Famous Forex Traders Of All Time

    The five most famous forex traders share common virtues such as strong self-confidence.
  3. Forex Fundamentals

    Buying Yuans as a Long-Term Investment: Risks and Rewards

    Examine the current state of the Chinese currency, the renminbi/yuan, and learn whether it is considered a good long-term investment.
  4. Investing Basics

    3 Key Signs Of A Market Top

    When stocks rise or fall, the financial fate of investors change, as well. There are certain signs that can reveal a stock’s course, and investors don’t need to be experts to spot them.
  5. Investing

    Asset Manager Ethics: Rules Governing Capital Markets

    The integrity of the capital markets needs to be kept at utmost importance for all investors. This article shows how to maintain the integrity while investing.
  6. Forex Fundamentals

    What Are the Best Hours to Trade the Mexican Peso?

    The best times to trade the Mexican peso are centered around economic releases, typically in the morning hours.
  7. Forex Fundamentals

    Oil & Currencies: Understanding Their Correlation

    Crude oil shows tight correlation with movements in many currency pairs.
  8. Forex Strategies

    Will a Rate Hike Appreciate The Dollar Even More?

    Many market participants expect the US Dollar to rise after the start of the next rate hike cycle.
  9. Forex

    How Much Leverage Is Right for You in Forex Trades

    It isn’t economics or global finance that trip up first-time forex traders. Instead, a basic lack of knowledge on how to use leverage is at the root of trading losses.
  10. Forex Fundamentals

    3 Reasons The Mexican Peso Is So Liquid

    Mexico's vast petroleum reserves and close proximity to the United States add considerable liquidity to the Mexican peso.
  1. Capital Markets

    Capital markets are markets for buying and selling equity and ...
  2. Equity Market

    The market in which shares are issued and traded, either through ...
  3. Transfer Risk

    The risk that a local currency cannot be converted into the currency ...
  4. Market Value

    The price an asset would fetch in the marketplace. Market value ...
  5. Bulldog Market

    A nickname for the foreign bond market of the United Kingdom. ...

    See LIBOR

You May Also Like

Hot Definitions
  1. Real Estate Investment Trust - REIT

    A REIT is a type of security that invests in real estate through property or mortgages and often trades on major exchanges ...
  2. Section 1231 Property

    A tax term relating to depreciable business property that has been held for over a year. Section 1231 property includes buildings, ...
  3. Term Deposit

    A deposit held at a financial institution that has a fixed term, and guarantees return of principal.
  4. Zero-Sum Game

    A situation in which one person’s gain is equivalent to another’s loss, so that the net change in wealth or benefit is zero. ...
  5. Capitalization Rate

    The rate of return on a real estate investment property based on the income that the property is expected to generate.
  6. Gross Profit

    A company's total revenue (equivalent to total sales) minus the cost of goods sold. Gross profit is the profit a company ...
Trading Center
You are using adblocking software

Want access to all of Investopedia? Add us to your “whitelist”
so you'll never miss a feature!