Spain’s largest construction group ACS is putting its wind and solar energy business up for sale, for a price estimated by Spain’s press at more than €4 billion.

ACS made the announcement late on Thursday, putting on the block its renewable energy business in Spain and internationally.

Spanish financial newspapers Expansion and Cinco Dias said the price would exceed €4 billion, including debt to be assumed by the buyer, while El Pais estimated a price of €4.5 billion to €5.billion. ACS shares were among the few winners in mid-morning trade, rising 0.66 per cent to €19.055 on a market that was down 1.11 per cent overall.

Spain’s press interpreted the sale as the latest stage in a battle between ACS and Spanish energy group Iberdrola, in which it is the main shareholder with a 12.6 per cent stake.

ACS, run by Real Madrid president Florentino Perez, has been trying for two years to boost its stake in Iberdrola to 20 per cent and get on the board, part of a broader diversification strategy.

Iberdrola, run by Ignacio Sanchez Galan and a major player in renewable energy, has launched several legal actions to rebuff ACS.

In selling its renewable energy assets, ACS would deprive Iberdrola of a key argument to prevent the company joining its board – a conflict of interests, the Spanish press said.

According to Expansion, ACS had already sounded out French group EDF, Germany’s EON and investment funds about the sale.

The assets on sale represent a total of 1,757 megawatts, with 1,056 megawatts of windpower in Spain, 352 megawatts of windpower internationally and 349 megawatts of solar power in Spain, ACS said in a statement to the Spanish stock market regulator CNMV.