Shares in Porsche fell more than 10% on Friday after Volkswagen said their plans to merge would not be completed this year as planned.Volkswagen announced late on Thursday that the merger would be delayed while they explore other ways to integrate.Porsche and Volkswagen agreed in 2009 to merge by the end of 2011, but have since faced legal obstacles.Porsche has faced lawsuits from investors in Germany and the US, and investigations into former executives.Volkswagen said that following discussions with Porsche, the companies "reached the conclusion that the planned merger with Porsche cannot be implemented within the time frame".The carmaker added that "other potential courses of action exist for achieving the goal of creating an integrated automotive group with Porsche".By lunchtime, Porsche shares were 12% lower. Volkswagen shares were down 1%. From/ BBC