RE:RE:RE:OPEC decides to cut another million barrels.....You can short anytime but if you did short at $1.00 you will need to cover when the share is up to $1.50, this is the reason you must have in your account always 100% + an another 50% so 150% just in case the share are going up and the brooker will buy the share to cover with your 150%. This is the way my brooker did explain that to me.