Résumé en anglais

The active management of a portfolio should not be appreciated only in terms of excess profitability vis-à-vis a reference benchmark. It is part of a complete process where a manager's superior expertise is supposed to exist 'upstream'. This paper aims to analyse the tie between forecasting ability and excess performance in active management. It limits itself to bond portfolio management, but takes into account the international environment. A simulation of choices of maturity and choices of market in an environment with four currencies will show a link between forecasting ability and the expectation of excess return. The opening of the international environment shows a superior potential for gain in comparison with domestic active management, but introduces a strong complexity.