This report describes a model that the Swedish National Debt Office has developed for the study of strategic decisions on the Swedish government debt portfolio. The framework is a Monte Carlo simulation model where different portfolio strategies are examined over a ten-year horizon. The objectives is to find a portfolio which, in accordance with the objective of the Debt Office, seeks to minimise costs with due regard to risk. Different possible portfolio strategies, in terms of currency compositions and target durations, are confronted with modelled stochastic financial variables [extract from http://www.rgk.se/english.htm].