Porsche shares flat at close after landmark $72 billion listing By Victoria Waldersee and Emma-Victoria Farr FRANKFURT (Reuters) - Porsche AG shares had a see-saw start on Thursday, after Volkswagen defied volatile markets to list the sports car brand at a valuation of 75 billion euros ($72 billion) in Germany''s second-biggest market debut. The shares closed at 82.50 euros ($80.74), returning to their issue price from the session high of 86.76 euros. Volkswagen priced Porsche AG shares the top end of the indicated range, and raised 19.5 billion euros via the listing to fund the group''s electrification drive. Cornerstone investors including Qatar Investment Authority, T. Rowe Price, Norway''s sovereign wealth fund and Abu Dhabi''s laid claim to 40% of the share offering. Some 25% plus one ordinary share went to the Porsche and Piech families via Porsche SE, Volkswagen''s largest shareholder which now has a blocking minority on the sportscar brand. The shares peaked at 86.76 in late morning. The share performance puts Porsche AG''s valuation at about 75.