This chapter deals with intermediaries in the financial sector such as banks and institutional investors. These actors are expected to play a central role in economic growth via the funding of investment because they are supposed to match creditors' desires (households) with borrowers' needs (firms) at a macroeconomic level. It aims to reassess the theoretical role of financial intermediation related to the allocation of savings in a context of a structural decline in overall investment for thirty years. To achieve this goal, it studies the evolution of financial intermediaries' behaviour in their capacity to finance investment and identifies the weaknesses of our current financial system which does not allocate optimally savings to firms' productive projects. Then it suggests some policy implications defining new forms of financial intermediation in which public financial intermediaries would have to play a greater role.