sentenced Banco Santander SA (STD) Chief Executive Alfredo Saenz to three months in jail and barred him from banking for the same period for making false criminal accusations in a case dating back to 1994.

Spain's Supreme Court Thursday sentenced Banco Santander SA (STD) Chief Executive Alfredo Saenz to three months in jail and barred him from banking for the same period for making false criminal accusations in a case dating back to 1994.

But one of Spain's most powerful executives is unlikely to serve the sentence because he has no prior criminal record, a court official said. Meanwhile, Saenz plans to appeal the ruling and remain at the helm of the euro zone's largest bank.

Santander said in a filing with Spain's stock market supervisor that its board "reiterated its confidence" in the bank's CEO. Saenz is credited with the successful expansion strategy that positioned Santander as a global retail banking powerhouse and the euro zone's biggest bank by market value.

A bank spokesman added that Saenz would appeal the Supreme Court's ruling with the country's Constitutional Court, in a legal process that could extend from two to four years and in the meantime suspends the sentence. Saenz also plans to appeal to Spain's Justice Ministry and file a request to commute the sentence.

The Supreme Court slightly watered down a ruling from a lower tribunal that in 2009 sentenced the CEO to six months in prison for making false criminal accusations when he was head of Banco Espanol de Credito SA (BTO.MC), or Banesto.

Saenz first made a name for himself by turning Banesto around after Santander bought it in 1994. He became Santander CEO in 2002 and played a key role in many of its cross-border acquisitions over the last decade, including landmark deals such as the 2004 takeover of the U.K.'s Abbey National PLC and the 2007 acquisition of Brazil's Banco Real.

Saenz couldn't be reached directly but his lawyers have denied he was involved in any wrong-doing.

The case against Saenz related to efforts made by Banesto in 1994 to recover a EUR3.8 million loan and involved four of the bank's clients.

Banesto filed a criminal complaint against the four clients in an attempt to force them to pay back debts, court documents from an earlier trial show. That complaint was later dismissed and the clients filed counter charges against Banesto and Saenz, accusing them of lodging a false criminal complaint.

Saenz disputed this claim, but a lower court ruled against him, sentencing Saenz to six months in prison in late 2009. The case then reached the Supreme Court, following an appeal from Saenz.