Thesis: The first chapter notes a change in the composition of private intergenerational transfers inFrance over time, from more intrahousehold transfers in the 1980s to more inheritance in thenew millennium. Using a three-period overlapping generations model, we show that a risein wealth inequality can influence the composition of these transfer. However, the share ofintrahousehold transfers in human capital accumulation and the extent of the preference tobequeath can influence this inequality. The second chapter looks at the role of the demographic boom on the prevalence of informal employment, with the context of Egypt. We introduce overlapping generations of heterogeneous education levels in a multi-sectoral model. After calibrating and simulating the model, we show that a temporary demographic boom of better educated workers can have long-run effects on non-formality rates, interacting with output and prices. We contrast this actual dynamic adjustment with counterfactuals, emphasizing the importance of demographics and private sector constraints on non-formality rates. The third chapter examines the heterogeneity of micro and small enterprises (MSEs) inMorocco. These enterprises are grouped into three categories: top performers, potentialgazelles and “others.” The paper finds that top performers tend to do relatively well inall areas examined. Potential gazelles, on the other hand, appear to choose their sectorsof economic activity differently and appear to face particular constraints when it comes toaccess to credit and the ability to link to other businesses. Moreover, while formal firmsappear to exhibit significant heterogeneity, informal firms are less heterogeneous, showing asmall upper echelon that can compete with formal firms, while others are not starkly differentform each other.