Cross rate is the derived currency
exchange rate between two countries with respect to a common
currency based on which official exchange rates of both the
countries are given. Traingular arbitrage refers to a possibility
where the cross rate is such that there is a possibility of buying
low and selling high. For example, in the question given:
- exchange rate for Turkish Lira (TL)
and USD ($) is $2/1TL. (in $/TL)
- exchange rate for Swiss Franc
(franc) and USD ($) is $4/1franc. (in $/franc)
- Based on the above two information,
the implied cross rate between franc and TL can be derived.
Therefore ($/TL) / ($/franc) = ($/TL) * (franc/$) =
franc/TL. From our example, the implied cross rate
between franc and TL is $2/1TL * 1franc/$4 = 1franc/2TL or
0.5franc/1TL.
- We see that the observed or quoted
cross rate between franc and TL is higher than the implied cross
rate and is given at 3franc/1TL as opposed to 0.5franc/1TL. This
means that there is a scope of triangular arbitrage involving the
three countries. Had these two cross rates been the same, then
there wouldn’t have been any scope for profit. But since the
implied cross rate is lower than the quoted cross rate, there is a
scope to buy cheap and sell dear in the foreign exchange market and
earn profits. One can buy 1 TL for 0.5 franc and sell that 1TL for
3 francs.
- Thus the picture looks like:
Case A: ($2/1TL)
Case B: ($4/franc)
Case C: (3franc/1TL)
Using the same information above, if
one has $100 to put to use in the triangular arbitrage scenario,
one can find out how much profit can be earned.
- Firstly, using case A to convert $
into TL, $2=1 TL or 1$= 1/2 TL or $100= 100*1/2 = 50
TL
- Secondly, using the observed cross
rate, TL is converted into franc. 1 TL= 3 franc or 50 TL=
50* 3= 150 franc.
- Thirdly, using case B, franc is
converted back into $. 1 franc= $4 or 150 franc=
150*4=$600.
- Thus, on spending $100 in
triangular arbitrage, the revenue earned is $600. Therefore the
profit earned through triangular arbitrage is revenue minus cost =
$600-$100 =$500.