When are margin calls triggered? The first version posted by BM says 33%, the second version by Agent says nothing about percentages and the wiki says 25% (http://wiki.bitshares.org/index.php/BitShares/Short#Market_Rules_for_Shorts).
The rules there state the following:
Let us discuss the rules that need to be fulfilled in order to successfully go short. Short orders can only get executed (i.e. filled) under these conditions:
There is someone willing to buy BitUSD at the price feed
AND Your short order offers the highest interest rate
AND Your price limit is lower than the feed (BTS per USD) or you didn't specify a price limit.
AND You have enough collateral to provide 2x backing at the feed price (amount of USD for short sale will vary with feed price)
OR Your price limit is higher than the feed (BTS per USD) and someone is willing to buy at your price limit.
I find this confusing. There are some AND conditions and then an OR condition, but it is not clear where the parentheses should be on evaluating those conditions. Where does the OR condition apply?
Based on how it is written, one might read it and think that if the "OR Your price limit is higher than the feed (BTS per USD) and someone is willing to buy at your price limit" were true, then you wouldnt need any of the others to be true (you wouldnt need collateral, etc). That is a clearly wrong interpretation.
Which statement does the OR actually match up with?
I believe the actual rules are like this:
In order to short you must fulfill one of these conditions:
* (Your price limit is higher than the feed) AND (someone is willing to buy at your price limit).
OR
* (There is someone willing to buy BitUSD at the price feed) AND (Your short order offers the highest interest rate) AND (Your price limit is lower than the feed OR you didn't specify a price limit).
Additionally, for either case, you must have enough collateral to provide 2x backing at the feed price (amount of USD for short sale will vary with feed price).
We need to clear this up. I'm not even sure if my version is correct.