SmithAmundsen had no duty to advise a client about a Securities and Exchange Commission investigation into allegations that the client operated a Ponzi scheme, a federal judge held.In a written opinion, U.S. District Judge Virginia M. Kendall of the Northern District of Illinois tossed a lawsuit alleging the client would not be facing an SEC enforcement action if SmithAmundsen had given it competent legal advice.The investigation did not fall within the scope of the law firm’s employment by the now-defunct Today …