I would just like to verify if I understood the IB web page correctly. If I traded crosses like GBP/JPY or EUR/GBP, and my account is in USD, is the margin required additive, e.g., for GBP/JPY, my margin comes from the conversion of GBP to USD plus JPY to USD (with commensurate leverage)? I would just like to understand why, at 50% leverage, 17500 units of GBP/JPY has a margin of 4698.99 at IB whereas the same order has a margin of 652.89 at OANDA (where basis of margin computation is just from GBP/USD)? I am using demos for both brokers. I sense I am misunderstanding something here?
I'd like to follow-up by clarifying the question with an example:
On a USD account, I'd like to buy 17500 GBP/JPY at the ask of 207.27. I compute the margin as follows (as indicated in the website):
On the Cross, I am buying GBP:
GBP: 17500 x 1.8642 USD/GBP = 32623.5USD, then x .02 margin= 652.47 USD
Now that I have my 17500 GBP, at the same time, I am selling JPY where 1GBP=207.27. Therefore 17500 GBP x 207.27 JPY/GBP = 3627225 JPY. Then:
JPY: -3627225 / 110.50 JPY/USD = -32825.565 USD, then x .02 margin = 656.5113 USD
Total margin for cross: 652.47 + 656.5113 = 1308.9813
1) Is this a correct margin computation for a cross?
2) If it is, how come I could never get this result on the "Check Margin" feature? The results are off by over $500 or more. I expect the results to be close to the computation (rate variation and all close to clicking 'Check Margin'). What am I not adding to the computation or what's wrong with the computation?
3) This example is just for long trades. Why is there a difference in margin between long and short of the same pair on 'Check Margin'? As I said previously, I was comparing margins with OANDA (since I am seriously considering automating ForEx trades with IB and my manual account is with OANDA). The margin calculation for them is more straightforward and just based on GBP for GBP/JPY and no difference between long and short trades :
Can anyone please help? Is is difficult to automate without the right formulae.