Let’s consider an economy in which n identical firms would finance investment projects that require one unit of capital whose output is stochastic and available free of charge to the company only. In this context of asymmetric information ex post, investors can obtain the output only if they pay the costs associated with monitoring (the cost of a single monitoring transaction being K). All investors are assumed as small when compared to the project in which they invest, each having 1/m units of capital, hence m investors are needed to finance a project. In case of direct financing, each investor monitors the enterprise total cost nmK
In the case of financing through a financial intermediary that centralises resources and investments on behalf of individual financing entities, the cost of monitoring will be nk.
But who controls the intermediary? Obviously controls exercised by individual investors are inefficient; therefore, it is much more preferable that, regardless of the realisation of the revenue by the intermediary, the broker offers a standard debt contract in which each depositor receives an amount of R / m for a deposit equal to 1 / m. The delegation of monitoring tasks to an intermediary is more efficient when the total costs are lower than those incurred in the case of direct lending: hence when nK + C < nmK (C being the cost of delegation of the intermediary’s monitoring tasks). If investors are "small" when compared to the projects (m> 1), the investment is profitable in terms of expected revenue (Ey> K + R) and there is a need for monitoring in the presence of asymmetric information. The intermediary mechanism is more efficient than direct funding when the number (n) of projects to be funded is sufficiently large.
Cucinotta G., Nieri L. (2005) "Le assicurazioni, la gestione del rischio in una economia moderna", Il Mulino editore. 
Desiderio Luigi, Molle Giacomo. (2005) "Manuale di diritto bancario e dell'intermediazione finanziaria", Giuffrè editore. 
Di Giorgio G. (2004) "Lezioni di economia monetaria", Cedam editore. 
Guida Roberto. (2004) "La Bancassicurazione: modelli e tendenze del rapporto tra banche e assicurazioni", Cedam editore. 
Locatelli Rossella, Morpurgo Cristina, Zanette Alfeo. (2002) "L'integrazione tra banche e compagnie di assicurazione e il modello dei conglomerati finanziari in Europa", Enaudi editore. 
Patroni Griffi and Ricolfi. (1997) "La distribuzione bancaria di prodotti assicurativi in banche ed assicurazioni fra cooperazione e concorrenza", Giuffrè editore. 
Quagliariello Mario. (2001) "I rapporti tra banche e assicurazioni in Italia e in Europa: aspetti empirici e problemi di regolamentazione", Luiss University Press.
Quagliariello Mario. (2003) "La bancassicurazione: profili operativi e scelte regolamentari", Luiss University Press. 
Ruozi Roberto. (2004) "Economia e gestione della banca", Egea editrice.
Editor: Alberto Maria SORRENTINO