Right now the only thing people are talking about is the economy, and chatter is everywhere. This week people are focusing in on the Loonies mach towards parity, which of course is exciting for Retire First, since it coincides with our recent launch of our foreign exchange department. So with the pleasure to announce our newest venture Retire First Foreign Exchange and the recent rise in the Loonies value, I would like to introduce the idea of the Big Mac Index to our readers.
The Big Mac index is a light hearted method to measure the percentage of overvaluation and undervaluation between two currencies, by comparing the prices of a Big Mac hamburger using the US dollar as the base value. Although certainly silly and not a perfect measurement of currency valuation, the Big Mac index, introduced by the Economist in 1986 does allow us to compare dollar power in over 120 countries around the world.
The premise is that the McDonald Big Mac is a consumer good common to all nation and allows us to compare purchasing power parity (PPP). PPP equalizes the purchase power between currencies for a given basket of goods in one country with a base country, which is in this case the Unite states. Ideally, in efficient markets, identical goods should have identical costs. PPP is arguably the most useful tool for comparing differences in the living standards between nations since it does account for the cost of living and the inflation rate.
Example: Big Mac Index as July 16, 2009 (view all countries)
| Country |
Cost in Local Currency |
Cost in US Currency |
| USA |
3.57 |
3.57 |
| Canada |
3.89 |
3.78 |
| Britian |
2.29 |
3.65 |
| Norway |
40 |
7.16 |
| China |
12.5 |
1.8288 |
| Sweden |
39 |
5.63 |
| Japan |
320 |
3.58 |
| Sri Lanka |
210 |
1.8268 |
Essentially, when using the PPP using the Big Mac theory we should be able to find the exchange rate, which for this theory, is the percentage of under or overvaluation of a currency.
If the US dollar to the Mexican Peso exchange rate is $1 USD to 15 Peso, and a US Big Mac cost $3 it should cost 4.50 Peso, based on PPP as seen below
(45/3) * (1/15)= 1
The Purchasing Power Theory states that formula most always equal one so that arbitrage will not exist, but if it doesn’t hold true and the price of Big Mac in Mexico is 60 Peso, then Mexican fast food owners could buy Big Mac in the US for $3, at a cost of 45 Peso and sell them in Mexico for 60 Peso, pocketing 15 Peso. Well this doesn’t sound appetizing; we have seen this situation in other industries, such as people buying cars in the US and bring them home to sell them for more in Canada.
So what does this have to do with currency valuation? In the above example, if a US Big Mac cost $3 and 60 Peso, there should be a PPP exchange rate of $1 US for 20 Peso, resulting in the peso being overvalued against the US dollar by 33% (20-15/15), according to the Big Mac Theory.
In theory, since an arbitrage opportunity exists above, the action of the Mexican restaurant owners selling pesos and buying US dollars would eventually drive the value of the peso down (depreciate it) and then dollar would appreciate, driving the economy to equilibrium. That is in theory of course, and in reality the actions of exploiting the Big Mac Index would not be substantial enough to move the exchange rate up or down- but in theory, if the Big Mac Index applied to all goods it would be.
Keep in mind that while the Big Mac index does allow a quick way to value currency with 120 countries around the world, it is only a lighthearted and entertaining way to explore PPP, and does have numerous flaws that should be considered before relying on the index for your currency decisions. But in the mean time, take some time to check out the Big Mac Index and compare the cost of your burger at your favorite travel destinations, and don’t forget to call Retire First for your next currency conversion.