Based on the work of Hellwig [12], this paper compares the implementation of the second best allocation (non traded solution) by a fmancial intermediary to the one achieved in a walrasian market in which individuals hold the assets directly (traded solution). In this framework, in which individuals have smooth preferences, the traded and non traded solutions are no longer welfare equivalent; in fact, the non traded solution allows for greater risk sharing than the traded one. This result, and contrary to Hellwig's work, shows that fmancial intermediaries do provide for a positive role in the economy.