“Illustrating just how critical Howard Stern is to Sirius XM Radio, worries over his lawsuit against the company hit the satcaster’s stock price Wednesday. It closed down 2%. Wunderlich Securities analyst Matthew Harrigan downgraded the stock to a “hold” from a “buy” rating. “Sirius’ current stock market valuation likely cannot accommodate the uncertainty engendered by the suit — even if it ends up being meritless,” Harrigan writes in a note to clients. Stern’s production company and agent Don Buchwald filed suit in New York Superior Court on Tuesday seeking stock awards they believe are due under Stern’s previous contract as part of subscriber growth bonuses,” according to Inside Radio.