Emilio Botin, Spain's leading banker, will not face charges for tax evasion, the National Court decided after an 11-month-long investigation.
The chairman of Banco Santander, his brother, Jaime, and 10 of their offspring were under scrutiny in connection with income from accounts at HSBC Holdings' private bank in Switzerland.
It was June 2011 when the National Court accepted a request from prosecutors to investigate the 12 subjects' tax returns for the years 2005-2009.
The Botin family said at the outset of the criminal probe that Emilio, Jaime and their children had already taken steps to "normalize" their respective tax situations.
"The regularization carried out by the accused can be considered correct and prior to the initiation ... of a procedure of inspection or verification," National Court Judge Fernando Abreu wrote in a ruling released Tuesday.
The case dates back to May 2010, when French tax authorities informed their Spanish counterparts about individuals with funds in accounts in HSBC Holdings' private bank in Switzerland.
At the request of Spain's tax agency, the 12 members of the Botin family presented taxpayer statements showing income from accounts at the bank.
Banco Santander is Spain's largest financial institution and Europe's No. 1 bank by market capitalization. EFE