(24)It is necessary that, over and above technical provisions, reinsurance undertakings should possess a supplementary reserve, known as the solvency margin, represented by free assets and, with the agreement of the competent authority, by other implicit assets, which is to act as a buffer against adverse business fluctuations. This requirement is an important element of prudential supervision. Pending the revision of the existing solvency margin regime, which the Commission is carrying on under the so-called ‘Solvency II project’, in order to determine the required solvency margin of reinsurance undertakings, the rules provided for in existing legislation in the field of direct insurance should be applicable.