In October 2008 , Grupo Santander announced that it would purchase the 75.65 % of Sovereign Bancorp it does not currently own . This would cosst approximately US$ 1.9 billion ( â 1.4 billion ) . In October 2008 , Grupo Santander announced that it would acquire the 75.65 % of Sovereign Bancorp it did not currently own for approximately US$ 1.9 billion ( â 1.4 billion ) : the acquisition of Sovereign has given Santander its first retail bank in the mainland United States .