I have been monitoring some minis for a few weeks out of interest when something confused and scared me. The strike price of a mini long on BHP (BHPKOD) suddenly went up dramatically for no apparent reason which effectively halved the value of the mini overnight. Does anyone know what could have caused this? Each previous day the strike price went up by less than 1c which I understand is an interest charge, but on this day 8/2/2013 it went up by almost $3! I am possibly interested in trading minis, but only if I understand them properly. Please help.
