The agency also said its investigation into other utilities including Eni and Enel would no longer cover price changes for contracts which had already expired or were due to expire.

The decision comes after the Italian government returned to the issue this week, allowing utilities to go ahead with changes to expiring gas and electricity supply contracts which the antitrust authority had previously suspended.

The antitrust agency said it had found evidence that Hera and A2A had only changed prices for contracts that had expired or were about to, meaning it no longer had grounds to investigate them.

On the contrary, Eni, Enel as well as Edison, Acea and Engie remain under investigation for the alleged improper price-setting.

The five energy companies were given five days to comply with an order to suspend all unilateral price changes they have introduced for open-ended contracts, with no clear or predetermined expiry date.

(Reporting by Alvise Armellini, editing by Giselda Vagnoni and Louise Heavens)