Europe’s highest court has ruled the Portuguese government’s so called golden shares in utility firm Energias de Portugal are illegal.
The arrangement gives Lisbon more rights than other shareholders.
The European Court of Justice said that was a “restriction on free movement of capital” and incompatible with EU law.
A similar ruling followed Lisbon’s attempt to block the sale of part of Portugal Telecom through golden shares.
Portugal currently owns about 25 percent of former state monopoly EDP through direct and indirect stakes.