JPMorgan soaked $150 million from based metals customers before crackdown

``The payment to JPMorgan included in a filing on Thursday illustrates the big profits made during a period when warehouse owners were under attack for exploiting exchange rules in order to collect more rent on stockpiled metals. But the loss also underscores how quickly the lucrative business model has unraveled after the London Metal Exchange cracked down on the practices over the past two years, making it harder for storage firms to capture big profits.''