In 1972, the company merged with Hidrogalicia and in the following decade it purchased various mining facilities, among which As Pontes (La Coruña) and Andorra (Teruel). Endesa began operation of the thermal plants of As Pontes (La Coruña), Andorra and Escatrón (Teruel and Zaragoza) and Litoral (Almeria), as well as the diesel-fired power plants of Ceuta and Melilla and the Ascó II nuclear power plant in Tarragona.
The Endesa Group was established in 1983 with the acquisition of the shares, which, at the time, the National Institute of Industry (INI) held in the Enher, Gesa, Unelco and Encasur companies. That same year, ERZ joined the Endesa Group.
In 1988, the first public tender offer for Endesa shares was launched. The Spanish government reduced its holding in the company to 75.6 percent.
Endesa was first listed on the New York Stock Exchange.
In 1991 Endesa acquired 87.6% of Electra de Viesgo, 40% of Fecsa, 33.5% of Sevillana de Electricidad and 24.9% of Nansa.
One year later Endesa purchased 61.9% of Carboex and acquired a stake in Electricidad de Argentina and Yacylec.
In 1993, it acquired 55% of the company Hidroeléctrica de Cataluña (Hecsa) and went on to purchase a stake in the Portuguese company Tejo Energía.
In 1994, a second public tender offer was launched. As a result of this transaction, the Spanish government reduced its stake in Endesa to 66.89%. During the year, Compañía Peruana de Electricidad y Distrilima was established with the participation of Endesa. Endesa also acquired 11.78% of the share capital of Sociedad General de Aguas de Barcelona (Agbar).
In 1995, an agreement was reached between Endesa and Banco Central Hispano and 9.7% of the share capital of the Argentinian electricity distributor Edenor was acquired, together with 7.2% of the second largest mobile telephone operator in Spain, Airtel.
In 1996, Endesa increased its stake in Fecsa y Sevillana de Electricidad to 75%.
In 1997, the consortium led by Endesa was awarded the contract for the second landline telephone operator in Spain, Retevisión. The third public tender offer was also launched for 25% of Endesa's share capital through which Endesa acquired a stake in the Latin American group Enersis.
In 1998, a public offering for 33% of Endesa’s share capital was launched, making it a private company.