Madrid, Apr 30 (IANS/EFE): Alfredo Saenz has resigned as CEO and vice chairman of Spain's Grupo Santander, the largest financial institution in the euro zone.

Saenz's departure follows an April 19 decision by the Spanish Supreme Court that partially overturned the pardon he received after a conviction for making false accusations against debtors during his 1993-2002 tenure as head of Banesto bank.

The reinstatement of the criminal conviction put Spain's central bank in the position of having to decide whether Saenz was a fit person to work in banking.

By voluntarily stepping down, Saenz, 70, allowed the Banco de España to avoid what could have been a difficult situation.

It was the Banco de España that named Saenz to run Banesto after the wounded bank was nationalized in 1993.

He remained as chairman when Santander bought Banesto in 1994.

Eight years later, Santander Chairman Emilio Botin appointed Saenz as CEO and deputy chairman of the group.

The bank quadrupled in size during Saenz's tenure as CEO, as assets rose from 358 billion euros ($468.7 billion) to 1.25 trillion euros ($1.64 trillion), Santander said Monday in a statement.

Succeeding Saenz as CEO and vice chairman is Javier Marin Romano, 46, who joined Santander in 1991 and became executive vice president of global private banking and asset management and insurance at Banco Santander SA in November 2009.