With the presidential election coming up in November the candidates are firing at each other like never before. Although much of the recent attention has gone to tax returns and emails, China still makes it into debates and speeches.

The Chinese deny it, however, the second largest economy in the world has time and time again been accused of devaluing its currency in order to advantage its own economy, especially by Donald Trump.

The ironic thing is that for many years, the United States government had been pressuring the Chinese to devalue the Yuan, arguing that it gave them an unfair advantage in international trade and kept their prices for capital and labor artificially low. Now that the Chinese are enacting emergency measures to devalue their currency, they are being blamed for bringing global uncertainty in markets. (For more, see: The Chinese Devaluation of the Yuan.)

Ever since world currencies abandoned the gold standard and allowed their exchange rates to float freely against each other, there have been many currency devaluation events that have hurt not only the citizens of the country involved, but have also rippled across the globe. If the fallout can be so widespread, why do countries devalue their currency?

To Boost Exports

On a world market, goods from one country must compete with those from all other countries. Car makers in America must compete with car makers in Europe and Japan. If the value of the euro decreases against the dollar, the price of the cars sold by European manufacturers in America, in dollars, will be effectively less expensive than they were before. On the other hand, a more valuable currency make exports relatively more expensive for purchase in foreign markets. (See also: Interesting Facts About Imports and Exports.)

In other words, exporters become more competitive in a global market. Exports are encouraged while imports are discouraged. There should be some caution, however, for two reasons. First, as the demand for a country's exported goods increases worldwide, the price will begin to rise, normalizing the initial effect of the devaluation. The second is that as other countries see this effect at work, they will be incentivized to devalue their own currencies in kind in a so-called "race to the bottom." This can lead to tit for tat currency wars and lead to unchecked inflation.

To Shrink Trade Deficits

Exports will increase and imports will decrease due to exports becoming cheaper and imports more expensive. This favors an improved balance of payments as exports increase and imports decrease, shrinking trade deficits. Persistent deficits are not uncommon today, with the United States and many other nations running persistent imbalances year after year. Economic theory, however, states that ongoing deficits are unsustainable in the long run and can lead to dangerous levels of debt which can cripple an economy. Devaluing the home currency can help correct balance of payments and reduce these deficits. (See also: Current Account Deficits: Government Investment Or Irresponsibility?)

There is a potential downside to this rationale, however. Devaluation also increases the debt burden of foreign-denominated loans when priced in the home currency. This is a big problem for a developing country like India or Argentina which hold lots of dollar- and euro-denominated debt. These foreign debts become more difficult to service, reducing confidence among the people in their domestic currency.

To Reduce Sovereign Debt Burdens

A government may be incentivized to encourage a weak currency policy if it has a lot of government issued sovereign debt to service on a regular basis. If debt payments are fixed, a weaker currency makes these payments effectively less expensive over time.

Take for example a government who has to pay $1 million each month in interest payments on its outstanding debts. But if that same $1 million of notional payments becomes less valuable, it will be easier to cover that interest. In our example, if the domestic currency is devalued to half of its initial value, the $1 million debt payment will only be worth $500,000 now.

Again, this tactic should be used with caution. As most countries around the globe have some debt outstanding in one form or another, a race to the bottom currency war could be initiated. This tactic will also fail if the country in question holds a large amount of foreign bonds since it will make those interest payments relatively more costly. (See also: Why Your Pension Plan Has Sovereign Debt in it.)

The Bottom Line

Currency devaluations can be used by countries to achieve economic policy. Having a weaker currency relative to the rest of the world can help boost exports, shrink trade deficits and reduce the cost of interest payments on its outstanding government debts. There are, however, some negative effects of devaluations. They create uncertainty in global markets that can cause asset markets to fall or spur recessions. Countries might be tempted to enter a tit for tat currency war, devaluing their own currency back and forth in a race to the bottom. This can be a very dangerous and vicious cycle leading to much more harm than good.

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