Great points janakisri,!
to add a few more thoughts to the second example above…
as I mentioned, you must always determine which currency is “base 1”
For 1.43 USD/GBP - GBP is “base 1” because it takes 1.43 US$ to buy 1 Pound
For 0.80 Euro per dollar - USD is “base 1” because it takes 0.80 Euro to buy 1 Dollar
Notice that these two exchange rates are inversely quoted …
You can also quote 0.80 Euro per dollar as Janakisri mentioned as
(1/0.80) USD per Euro or 1.25 USD per Euro. Notice that in both quotes - 1.25 USD per Euro and 1.43 USD per GBP, the foreign currency is “base 1”
These exchange rates now similarly quoted will behave the same way, where as the 0.80 Euro per dollar will behave in an opposite fashion as the foreign currency appreciates or depreciates against the dollar
Here is more detail for clarity…
as mentioned you can also quote 0.80 EUR/USD as 1.25 USD/EUR and if you need to take a long position in EUR, if you quote it one way, you will need to short the EXCHANGE RATE and the other you will need to long the EXCHANGE RATE in order to profit when EUR appreciates…
Lets say I am US firm with operations in germany… of course I am exposed to appreciating Euro against the dollar… therefore in order to hedge my risk, i need to GO LONG Eur in the futures market against the dollar, that way when I lose as Eur appreciates against dollars because I need to pay my european employees… I will gain as my Long EUR futures contract appreciates, neutralizing this exposure. Now that we know what position we need to take, we need to determine whether you should “buy or sell the EXCHANGE RATE” in order to be long the EUR. Notice that I did not say we need to determine whether you should buy or sell EUR, we already know we need to buy EUR. What I said was we need to figure out that given a certain quoting convention, whether we should buy or sell the EXCHANGE RATE in order to take a long position of EUR against dollars
Now this is how we determine this… If the quote in the futures market is 0.80 EUR/USD, or re-written 0.80 EUR / 1.00 USD, what needs to happen to the EXCHANGE RATE for EUR to appreciate against the dollar?
IF I want to buy $1, it will now cost me 0.80 EUR. What if the exchange rate moved to 0.70 EUR/USD? In order to buy the same $1, it will now cost my only 0.70 EUR! Hence Euros have appreciated. Therefore using this quoting convention… I need to take a short position in the exchange rate in order to profit when EUR appreciates against the dollar.
Now for the inverse example… If instead the quote in the futures market is 1.25 USD/EUR, or re-written 1.25 USD/1.00 EUR, what needs to happen to the EXCHANGE RATE for EUR to appreciate against the dollar?
IF I want to buy 1 EUR, it will cost me 1.25 USD. What if the exchange rate moved to 1.40 USD/EUR? In order to buy the same 1 EUR it will now cost my 1.40 USD! Hence Euros have appreciated. Therefore using this quoting convention… I need to take a long position in the EXCHANGE RATE in order to profit when EUR appreciates against the dollar.
You should now see that it is irrelvant which way currencies are quoted as long as you take either a long or short position in the exchange rate that will make you a profit when EUR appreciates.
hope this helps!