mpjordan,
I beleive you are incorrect here and post my reasoning.
1 - The trades are not closed instantaneously thus leaving you exposed to price risk.
2 - Trades can not be exchanged between platforms so the "arbitrage" you talk about can not be closed by entry trade cantor being cleared by exit trade
IG.
3 - The guarentee of 7 points is incorrect as you have no way of closing these trades against each other.
Note - You are assuming you can trade cantor against ig which you cannot and so therefore you are trading a spread and not an arbitrage (riskless profit).
For a trade to be an arbitrage you need 2 platforms of execution that accept the same contract both buy and sell. You can do this on voice arbitraging screen only in spreadbetting. For example if I heard dow was
[email protected] on voice trading and
[email protected] on screen that is a potential as I can instantly execute the trade and that would constitute an arbitrage or riskless profit. By trying to trade across different spreadbetting platforms this is not an arbitrage merely a spread trade, ie you are betting the spread of the platforms will realign to a point where you will make money. If they trade in a 5 point range until close then you make nothing.
I hope this clears this up but if you feel it is incorrect please reply. I am a energy trader and trade electricity which is one of the few commodities wher you can happily sit and arbitrage all day long due to the inefficiency of the market place.
Cheers,
Superboy