Spain's National Court said it is investigating seven current and former HSBC executives in the private banking business accused of money laundering and criminal organisation.
HSBC's Swiss banking unit has been investigated in several countries after leaked documents suggested it helped wealthy people around the world dodge taxes.
A former IT employee, Herve Falciani, gave the data to French tax authorities in 2008 and France shared it with Spanish authorities and other governments.
Judge Jose de la Mata ruled on Thursday to investigate the Swiss banking unit's former chairman, Peter Widmer, as well as Clive Bannister and Christopher Meares, who were CEOs in 2006 and 2007 respectively, and four more employees.
The judge found evidence that the executives worked with Banco Santander and BNP Paribas to transfer funds at least until 2008 to avoid taxation in Spain.
HSBC declined to comment.