Currency arbitrage, which price to use given 3 quotes

Hi guys,

I don’t know if anybody gets confused on this, but it sure gives me a diffcult time:

Context: You are being offered 3 currencies where 1 is mispriced (I think everyone knows what I talking about at this point).

Ex:

EUR/USD: 0.7-0.7010

USD/GBP: 1.7-1.7010

EUR/GBP: 1.2-1.2010

ENUR/GBP (implied): 1.19-1.1924

In the event of an arbitrage, I know which direction to go: USD–>GBP–>EUR–>USD

But then which bid-ask do you use.

And now I am at this mechanical stage where I just use memorization: ASk price–>Bid Price–>Ask price.

Anybody can exaplin which price to use?

Or did I justed asked an absolutely stupid question.

Of course all arbtriage will be: Buy–>Sell–>Buy, from your perspective.

I already did: http://financialexamhelp123.com/triangular-arbitrage/.

^ never been to your site before S2000, it is quite impressive

Thanks!

It’ll be more so as I get more articles written. At least, I hope that it will be.

As always, you are the best, and the most valueable asset for this web and CFA institue as well.

I would argue S2000 is a liability to the CFA institute…think of the amount of money he’s cost them by helping people pass the exam and not paying fees to retake cheeky

More power to him though

stupid question but is there a quicker way to tell which direction to go for abritrage profit without calculating both directions… i.e USD–>GBP–>EUR–>USD or USD-EUR-GBP-USD

or is the whole point of the question to calculate both ways

The first thing I do is calculate the inverse of each given bid/ask so that I have all the possible exchange rates in front of me (the bid/asks switch when calculating the inverses.) If the problem gives you the bid/ask for USD/EUR you’ll now also have the bid/ask for EUR/USD as well. It only takes a minute but actually saves time later on in the calculation

Then I draw a triangle with a currency at each point. I start with 1 dollar and go clockwise. Figuring out which exchange rate to use should be easy with all the possibilities already calculated. Remember, you should use the exchange rate you would prefer not to use–the one which will get you the lesser amount of foreign currency. Because you have it in format FOREIGN/BASE this will be the bid.

If you don’t calculate an arbitrage profit try again by going counter-clockwise. You may have to do the calculation both ways.

Initially these problems seem difficult but they become easy points with practice.

It’s not a stupid question, but there’s no quicker way.

After you’ve done a ton of these you’ll have a better feel for which direction is likely to give an arbitrage profit (and you’ll get a profit in at most one direction), but there will still be times when you’ll try one way, get a loss, and have to try the other way.

Sorry.

thanks for your replies

My pleasure.

S2000magician,

very nice way to simplify the calculation on your website.

thanks.

You’re welcome.