A Brattle principal advised BCP, one of the largest retail banks in Europe, in connection with an in-depth investigation carried out by the Portuguese competition authority of a proposed merger with BPI, one of its smaller rivals. Economic analysis entailed evaluating the effect of the proposed merger on the price and quantity of different banking products in the retail and small business banking sectors. Also investigated the role of other competitors to determine the extent to which they might, or otherwise, constrain the ability of the merged entity to raise prices and/or restrict output.