the main one: right before new disclosure, regulation, and taxation laws came into effect, he sold 50% ownership stake in his holdings of the shell corp to his wife for $1, so that he would not be subject to the new laws.
in general: one does not have to literally break the law to be asked to resign by your citizens. that is not, and should not be, the standards to which we hold our leaders.
Do you know what exactly he has he done (to have to resign in shame)?
It's just odd that there are no details within the articles, nor from the people that are trying to get him to resign.