This paper analyzes the productive differences of banking among countries. It proposes a Malmquist type index that allows intercountry productivity differences to be broken down into pure technological differences and differences due to environmental effects. The most relevant feature of this index is its symmetry, since it avoids the problem of measurements being sensitive to the choice of the benchmark country. This index is used to explain the productivity gaps of banking industries across four major countries in Europe as well as the productivity gains that banks could obtain using alternative technologies or with different environments. An output distance function is defined and the stochastic frontier approach used to carry out the comparison.