The agreement, which is being carried out by Enel’s wholly-owned Enel Energy Europe subsidiary, was agreed three months ago, the company said.

The transaction, which is scheduled to occur on June 6, 2007, will furnish Enel with an additional 14.98% of Endesa’s capital stock.

Of the 158.6 million Endesa shares, 74.1 million will be received through the equity swap with UBS, with the remaining 84.5 million coming from the equity swap with Mediobanca.

According to Enel, the share swap initiative follows the authorization provided by the Spanish Energy Authority on April 26, 2007 to raise the company’s stake in Endesa up to 24.99%.

A joint bid to acquire Endesa was recently launched by Enel and Spanish construction and energy firm Acciona, which beat a rival bid from German utility E.ON.