A criminal investigation into the collapse of the brokerage firm MF Global and the disappearance of about $1 billion in customer money is now heading into its final stage without charges expected against any top executives. After 10 months of stitching together evidence on the firm’s demise, criminal investigators are concluding that chaos and porous risk controls at the firm, rather than fraud, allowed the money to disappear, according to people involved in the case. The hurdles to building a criminal case were always high with MF Global, which filed for bankruptcy in October after a huge bet on European debt ... (full story)