From previous discussions, as I recall, the gist was that there were a whole bunch of differing arrangements concerning duration. Also there were a variety of ways of achieving the short. I believe, in Australia, naked shorting is outlawed, so all shorts needed to be done with borrowed shares on the ASX/Chi-X. Not sure how that constraint impacts warrants traded overseas on other exchanges. Secondly apart from the straight borrow and trade arrangements through brokers, most retail shorters (if I understand the discussions correctly) were done via CDF's.
I believe at some point
@tutor explained that borrowing durations and recalls were not necessarily an absolute constraint as the brokers could usually borrow shares from other borrowers/lenders to use to return when called.
As far as the mechanism of the arrangements i believe it was explained that a fee is paid by the borrower (8%, was it?) and collateral was lodged, I believe for the value of the shares borrowed, which could be used by the collateral holder while the shares were on loan (including purchasing more shares). When the shares were returned the collateral was also returned. I understand there the fee is time based, so it is akin to renting the shares, but I can't recall what @tutor explained was the usual amount and for how long. I just have that 8% figure lodged in my brain.
My overriding impression from the discussions was that there were a large number of different arrangements with just the above bits (excluding the fee amount) as the consistent elements, except perhaps for CDF's
As it is not something I have an interest in doing (in fact I can't through any of the three trading platforms I am using) I kind of just stored it away as a curiosity so I am a bit loose on the details.
I think at one stage we were collectively focusing on how long the shorts could hold out, but after 18 months of this we got over expecting any borrowing duration to have a noticeable impact because they were pretty clearly covering and then re-shorting in cycles which made it kind of irrelevant, and the explanations from tutor kind of made it apparent that given the actual share shorted might be borrowed from a borrower who borrowed from another borrower, etc that short of a massive sentiment uplift the covering was likely to be well controlled.
That's what I recall, anyway.
