The figure cited was 6.0 %. It was cited by the author from an earlier article the author wrote. Do not know when that article was written.
Third, in futures mkts there is NO borrowing by anybody from anybody, except sometimes in the case of physical delivery (the brokerage will lend the client the capital to pay for the goods, on the condition that he sell them back into the spot mkt immediately).
Perhaps borrow was a poor choice of words by the author. As you stated, Guaranty is much better. That could be a simple England verse States problem. For Example - They refer to rent as let over there.
Other than those points, your cited source may have a clue as to what he's talking about.
Well he is from England. You can post comments to his article if you like.
I was raised in Scotland, m’friend. The English futures regs don’t differentiate as to ‘’margin’’ from the US regs — it’s purely and simply a performance bond, a guaranty if you like.
However, the UK futures regs allow for substantially less mkt transparancy and much larger positions than US regs do.
You could ask Nick Leeson about that, for instance.