Executives and directors at Impac Mortgage Holdings are named as defendants in a number of class action lawsuits alleging insider trading. The lawsuits allege that Impac executives and directors made millions in profits at the expense of the company’s shareholders. Impac has been one of the leading Alt A MBS issuers, although the company’s volume was down 19.9 percent in 2005 as it funneled more production through other securitization conduits. …