PARIS EDF (EDF.PA) shares fell to an all-time low on Thursday after a newspaper said the French power group may have to pay back 8.8 billion euros ($11.4 billion) to customers because of a court ruling that overturned part of its pricing plan.
The issue relates mainly to part of the electricity bill calculated by France's CRE energy regulation commission amounting to more than 30 percent of the total sum paid by consumers.
France's Council of State, the country's top administrative court, on Wednesday overruled the way these tariffs had been set for the period from mid-2009 to mid-2013.
State-owned EDF's ERDF unit, which delivers electricity sold by suppliers to end-users, may have to reimburse 1.9 billion euros for each year as a result, Le Parisien newspaper said, without specifying how it calculated the number.
ERDF has also received 1.2 billion euros too much towards investments during the period, the paper added, bringing the total to 8.8 billion.
"The figure seems huge and won't help the stock to recover," said Renaud Murail, a portfolio manager at Barclays Bourse. "If it is confirmed, it risks creating great uncertainty surrounding the group's outlook."
EDF stock fell as low as 13.39 euros and was down 3.3 percent at 13.805 euros at 6:15 A.M. EDT. It has fallen by nearly a quarter since mid-September.
The CRE said on Thursday it was too soon to understand the impact of the ruling. It planned to start work on a new tariff level in the coming weeks, which will apply retroactively.
The head of ERDF, Michele Bellon, said in an emailed statement that she was "unaware of any possibility of reimbursement."
The final decision on tariff levels rests with the government.
(Reporting by Benjamin Mallet and Alexandre Boksenbaum-Granier; Writing by James Regan; Editing by Lionel Laurent and Mark Potter)