In October 2011, Banco de Portugal imposed a capital surcharge on banks offering ‘superdeposits’, i.e. deposits with a remuneration deemed excessive. This policy measure was later adjusted and reinforced in April 2012. Its motivation was macroprudential in nature, addressing a significant financial stability concern. It was an early example of such type of measures in Portugal, before the current institutional framework of macroprudential policy was in place. At the time, Portuguese banks were aggressively trying to increase their funding through deposits, in a context of very unfavorable macroeconomic conditions and the associated materialization of credit risk. Excessive competition for deposits was amplifying bank losses by raising interest expenses and thereby increasing the risks to the stability of the Portuguese banking system. Furthermore, the higher deposit rates were passing-through to the loan rates, thus contributing to further deepen the recession. The available evidence discussed in the paper, based both on macroeconomic data and on microdata on individual deposits collected from banks for monitoring purposes, suggests that the imposition of the capital surcharge contributed to contain the war for deposits amongst Portuguese banks.