Nineteen of the 20 biggest Portuguese multinationals are using a letterbox company in the Netherlands to reduce their tax bills in their home country, according to a new report by the centre for multinational research Somo.

Somo estimates Portuguese multinationals shifted at least €2.5bn in profits to the Netherlands between 2009 and 2011.

The institute bases its claims on information from the IMF, the OECD and the Dutch central bank.

Read the report