The surprise announcement appeared to cut short what many investors had viewed as an inevitable battle of attrition over a deal that would have joined two of Hollywood’s biggest studios and TV networks from TNT to Fox News. Still, some investors wondered whether the move could be a shrewd effort to drive down the stock, prompting Murdoch to re-enter the fray later on. “This could easily be part of their negotiating strategy,” said Brett Harriss, an analyst with Gabelli & Co, who said Fox could still try again later.