I am used to the CBOE pricing for indexes, so am a little confused by the XJO. Can someone please confirm if this is correct:
I sell one call contract. The bid is 81, therefore I get a credit of $810 because each point is worth $10.
I buy one call contract. The offer is 71, therefore I pay $710.
If I do this as as a credit spread, the margin is $250 per contract because the exercise intervals are 25 points.
If this was a US index, eg, SPX, it's pretty much the same as equities, where one contract is equal to 100 shares, so a bid of 20 would give a credit of $2000, and an exercise interval of 5 in a credit spread would mean a margin of $500 per contract.