Originally Posted by
SF_trotter
In my case I don't need to look up the interbank rate because my receipt explicitly says the markup was 3.75%:
"This transaction is based on Reuters Wholesale Interbank exchange rate plus 3.75 percent international conversion margin."
In that case, you're simplest path is to simply replace "WSJ" with "Reuters Wholesale Interbank" and calculate the rate.
For the calculation:
1) first of all, we need to think about this in terms of USD/AUD, which means the fx rate will be less than 1
2) take the amount you were charged in USD and divide by the amount you were promised in USD
3) this will provide you with the exchange rate you were offered --0.90991 based on today's rate (I've already tacked on the extra points here)
4) divide the result from #3 by 1.0375, and
that's your Reuters rate, 0.87703 today
5) for "which means I would have been charged", the proper amount is your USD price multiplied by the result from #4
I don't mean to offend you in the event you can do pull off this stuff in a heartbeat on your own. Part of the reason that I've sunk so much time into this exercise is that I recently started a hedge fund that entails a currency component (in particular, I'm trying to figure out a way to short JPY and, simultaneously, go long on CNY), so I'm brushing up on some of the things I learned 10+ years back in school.