Probabilités pour scientifiques et ingénieurs

This dissertation endeavours to shed light on the paradox of the persistence of informal finance in urban African markets despite the emergence of a vibrant microfinance sector. To do so, it analyses the rationale of the financial choices of the micro-entrepreneurs operating in the markets of Ouagadougou (Burkina Faso). In particular, a careful examination of the motives driving the combinative use of informal and formal microfinance is carried.

In order to lay deep theoretical foundations to this analysis, this thesis develops a model describing the financial behaviour of the micro-entrepreneurs in the presence of hyperbolic preferences and social influences. The solution of this model shows, inter alia, that the financial choices are not solely driven by economic motivations but also by social motivations. This result is confirmed by empirical observations which show, among other things, that social relations play an important role in explaining the persistence of informal finance.

Besides, it appeared also that the combinative use of informal finance and microfinance can be explained, on the one side, by the fact that the motives driving the demand for informal and for formal finance are not always the same and, on the other side, by the fact that these two types of financial mechanisms are more likely to be used as complements than as substitutes.

Ultimately, this thesis unfolds a new perspective for apprehending the coexistence of informal and formal microfinance. Informal finance is no longer considered as a makeshift, but as an integral part of the financial landscape of the Sub-Saharan urban financial markets. Therefore, microfinance institutions and policy makers ought to adopt a more positive and pro-active attitude vis-à-vis informal finance.