Telefonica's César Alierta will be replaced as executive chairman by deputy José María Álvarez-Pallete on April 8, the Spanish telecom giant has revealed.

Alierta is stepping down after spending around 16 years in the leadership role but will remain on the operator's board as executive chairman of Fundación Telefónica, the operator's social development initiative.

Álvarez-Pallete has been Telefónica 's chief operating officer since 2012 and has been largely responsible for the operator's program of digital transformation. He has previously held the roles of chief financial officer, executive chairman of Telefónica Internacional and executive chairman of Telefónica Europe.

Telefónica's board will discuss Alierta's appointment of Álvarez-Pallete as the next executive chairman at a meeting scheduled for April 8.

Alierta, now 70 years old, is credited with turning Telefónica into one of the world's biggest service providers, with operations that span Europe and Latin America, although the former state-owned monopoly has recently been rolling back the borders of its empire to focus on a few core markets, including Brazil, Germany and Spain.

As noted by Reuters, Telefónica's market capitalization has fallen from a peak of €100 billion ($112 billion) in 2007 to around €48 billion ($54 billion) currently.

The operator's share price was trading up 1% in Madrid by mid-afternoon on Tuesday.

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Among other things, Telefónica is now regarded as something of a pioneer in the fields of SDN and NFV, having announced ambitious plans for the transformation of its networks in early 2014.

Although the so-called Unica project has encountered its share of problems, Telefónica unveiled plans to begin rolling out virtual network functions in Germany this year during an exclusive interview with Light Reading at last month's Mobile World Congress. (See Telefónica CTO: It's Time for Unica Phase II.)

Chief Technology Officer Enrique Blanco sees an opportunity to virtualize networks while getting rid of legacy technology as it integrates E-Plus Service GmbH & Co. KG , a business it bought from Dutch incumbent KPN Telecom NV (NYSE: KPN) in 2014, with its local subsidiary.

Meanwhile, Chief Information Officer Phil Jordan is leading an overhaul of the company's back-office systems across its various national markets. That project involves a revamp of billing, charging, analytics, customer experience management and other systems. (See Telefónica Bets on IT Transformation.)

Jordan has said the process of introducing new IT systems while maintaining legacy ones is like changing the tires while driving a car.

Telefónica's digital initiatives have also included the launch of over-the-top services, designed to counter the threat from web-scale players in this area.

— Iain Morris, , News Editor, Light Reading