Your broker has a duty to disclose all risks from investing with him and his company. He also has an obligation to tell the truth. If he misleads you, including failing to disclose a major risk to your investment, you can sue him personally.
In late 1999, Boston-based securities analyst Harry Markopolos discovered Bernard Madoff was running the largest Ponzi scheme in world history. His team pursued the truth for nearly a decade, only to find no one would listen.
JP Morgan could be "complicit", i.e. aiding and abetting the Madoff Ponzi scheme, by omission -- that is not fulfilling its duty as a fiduciary -- as well as by commission, according to white collar lawyers I have consulted today.