Econ 101: What is a strong dollar?

Should the United States seek a strong dollar or a weak dollar? The answer to the previous question appears obvious but what exactly does a strong or weak dollar mean? As I write this the exchange rate of the dollar for the Euro is 0.80 Euros per dollar. Is that strong or weak? Three weeks ago (January 9) a dollar would buy 0.839 Euros. Was that too strong, about right or weak? On what basis should we judge that question? Eleven months ago the rate was 0.95 Euros per dollar. Ten years ago the rate was 0.62 Euro/USD. One thing that is clear is that the rate varies a lot and thus the price of American exports to the rest of the world and of imports by the U.S. from the rest of the world also vary a lot. This makes business planning difficult.

According to Your Dictionary:

“strong dollar – Investment & Finance Definition. A situation in which the U.S. dollar can be exchanged for a relatively large amount of another currency. A strong dollar makes exports relatively expensive because foreign purchasers have to pay more, in their currency, for the goods.” This is a somewhat helpful definition.

According to Investopedia, “strongweakdollar”,

“A strong dollar occurs when the U.S. dollar has risen to a level against another currency that is near historically high exchange rates for the other currency relative to the dollar.” This is a useless definition.

Back in the gold standard days, the prices (exchange rates) of most currencies for most other currencies were fixed because the value of each currency was fixed to an amount of gold. It was important in those days for the balance of payments between countries (the net inflows and outflows of a country’s currency as a result of its imports and exports and investment flows) to be roughly balanced over the long run. In fixed exchange rate systems (like the gold standard) a balance of payments deficit was paid for by an outflow of the deficit country’s currency (ultimately gold). The resulting reduction in the money supply of the deficit country would reduce domestic prices, making domestic goods and their export prices cheaper and the domestic prices of imported goods relatively more expensive. Thus in deficit countries their now cheaper exports would increase and their now more expensive imports would decrease. These economic adjustments would correct (eliminate) the imbalance of external payments.

The above summary of the adjustment process under a gold or similar fixed exchange rate world draws on two features of prices and exchange rates. The first is that the prices of American goods to the French, for example, depend on the U.S. dollar prices times the exchange rate of the dollar for the Euro. If either the dollar price of a product increases or the exchange rate of dollars for Euros increases (it takes more Euros to buy a dollar), the product becomes more expensive in France. Similarly, under the same circumstances French goods become cheaper in the U.S. Thus the French will buy less from America and Americans will buy more from France. This will reduce any balance of payments surplus in the U.S. or worsen a balance of payments deficit.

The second feature is that other things equal an increase in the money supply in a country tends to reduce its purchasing power, i.e. to increase domestic prices in general (inflation). So a country with an external balance of payments deficit paid for by an outflow of its currency (gold) will reduce the money supply and thus prices in that country and eliminate the external deficit.

While we are at it, it should be clear that the external balance of payments that matters is between each country and the rest of the world. A balance of payments between the United States and Mexico, to take a random example, is totally irrelevant to whether currencies (gold) are flowing in or out of the U.S. on net.

Consider the balance of payments between one household and the rest of the world. The breadwinner or winners have a large balance of payments surplus with her or their employer(s)—their salaries—and a balance of payments deficit with every one else. The deficit with the grocery store will go on forever and simply doesn’t matter as long as all external deficits don’t excess the surplus with her employer (in the long run). President Trump, please take note.

In fixed exchange rate systems, the terms “strong” or “weak” currencies are generally not used. The overall balance of payments is the important thing. However, a strong currency might mean that it is “over valued” and thus producing a balance of payments deficit that will need to be corrected by a domestic deflation. This is what Greece had to do a few years ago within the single currency Euro area to restore its balance of payments equilibrium. A weak currency might mean the opposite—an undervalued currency that produces a balance of payments surplus, which will be eliminated by the domestic inflation resulting from a net currency inflow. Clearly neither a strong nor a weak currency is desirable. The ideal is a goldilocks middle ground of not too hot and not too cold but just right balance of payments balance.

Where currency exchange rates are not fixed to each other but determined in the foreign exchange market by the supply and demand for currencies, the adjustment of balance of payments surpluses or deficits occurs via adjustments in the exchange rate rather than net flows of currency in and out that increase or decrease domestic prices. Market exchange rates are determined not only by the imports and exports of a country (the trade balance) but also by investment motivated currency flows (capital flows). Thus monetary policy and interest rate differentials between countries can influence where investors chose to invest. If the Federal Reserve increases its policy interest rate and raises market interest rates as a result, unless the ECB also increases its interest rates, some interest sensitive investments are likely to move from Europe to the US, increasing the dollar’s exchange rate with the Euro in the process. The risks attached to investments are also important, and financial market disturbances abroad can often precipitate capital flows into the U.S. even with lower U.S. interest rates (the so called safe heaven phenomenon).

Central bank intervention to influence exchange rates for countries with floating rates is considered a violation of the rules of free trade. But when central banks raise or lower their interest rates without coordinating with other central banks this is exactly what happens. This makes it difficult to know whether a country is playing by the rules or not. But this surely pushes what can be learned in Econ 101 to its limits. You might consider Econ 201.

So what does a strong dollar or a weak dollar mean, and is a strong dollar a good thing? There is a sense in which we might speak of a strong dollar as meaning “a favorable terms of trade”. If a country’s international payments balance at prevailing exchange rates, a higher ratio of export prices to import prices enables the country to import more for given exports than when the (real) exchange rate is “weak.” This reflects higher domestic productivity relative to that of foreign competitors and such strength is clearly a good thing. I assume that this is what Secretary Mnuchin meant in his unfortunate discussion of weak and strong dollars at Davos last week.

If you are up to a deeper plunge, take note of the fact that the widespread use of the U.S. dollar in international reserves requires the U.S. to have a balance of payments deficit in order to supply the world with those dollars. This is one of several reasons why a truly international reserve asset such as the IMF’s SDR should replace the dollar in international reserves. See: “Why the World Needs a Reserve Assets with a Hard Anchor”