First chapter aims to quantify the role of trade in capital goods in cross country income differences. I construct a multi-country general equilibrium model of trade along the line of Eaton and Kortum (2002) and Alvarez and Lucas (2007) and introduce trade in capital goods and capital accumulation. In this framework, comparative advantage and the costs of international trade determine the pattern of production, specialization, and trade. I calibrate the model for 53 countries by estimating trade barriers and calibrating productivity parameters to match the bilateral trade data in 1996. The model is used to analyze full trade liberalizations. I find that removing barriers on investment goods accounts a large portion of reducing cross-country income differences and welfare gain. Counterfactual exercises suggest that developing countries gain relatively more than developed countries. In the second chapter, I focus on the impact of free trade on exportimport ratios in two different sectors. I employ a multi-country general equilibrium model of bilateral trade patterns along the line of Eaton and Kortum (2002) and Alvarez and Lucas (2007). I calibrate the model for 20 countries by estimating trade barriers and calibrating productivity parameters to match the bilateral trade data in 1996. The model is used to analyze full trade liberalizations. The impacts of free trade are predicted to be an increase in the export-import ratios in the comparative advantage sector and a decline in the comparative disadvantage sector, on average. In developing countries the average percentage change in export-import ratios exceeds the average percentage change in export-import ratios in developed countries. Finally, in the third chapter, I focus on the intergenerational human capital transmission. I develop and calibrate a theoretical model that considers three mechanisms of intergenerational transmission of human capital: (i) persistence in learning ability; (ii) parental investment in child’s human capital; (iii) higher teaching productivity of parents with more human capital. Within this framework, I find that (i) and (ii) plays important roles while (iii) does not. In addition the model generates the documented fact that higherwage parents spending more time teaching their children in spite of the higher opportunity cost. I asses the role of nature and nurture effects in intergenerational persistence of earnings and I find that nature accounts a large portion of the intergenerational persistence in earnings. I also quantify the relative importance of these mechanisms on wage inequality. / text

Le capital-investissement parait jouer un rôle essentiel dans la croissance des entreprises. Pourtant les liens entre modèles d'investissement et croissance restent mal compris. De plus, depuis quelques années, les doutes s’accumulent sur la compatibilité entre valorisation financière et développement pérenne et vertueux des entreprises, en particulier matures. Centrée plus spécifiquement sur le cas des entreprises de taille intermédiaire (ETI), cette thèse montre qu’une forme de capital-investissement, que nous appelons le « capital-régénération », demande à être mieux conceptualisée pour favoriser les dynamiques de croissance soutenables et outiller les politiques publiques en matière de financement des entreprises. Le capital-régénération, contrairement à la segmentation classique du capital-investissement, est moins lié au stade de développement des entreprises qu’à la nature de la croissance visée. Au lieu de porter sur une augmentation des performances à partir des produits existants, la thèse met en évidence une autre forme de croissance dite « générative », liée à l’innovation et qui s’appuie sur la dynamique de régénération des produits et des ressources de l’entreprise. A partir d’une analyse des besoins en financement des ETI, ainsi que de cas approfondis issus du portefeuille de Bpifrance, la thèse montre que le déficit de croissance des ETI ne s’explique pas par un défaut de capital (« equity gap »), mais plutôt par un manque de valorisation de la croissance générative par les modèles d’investissement classiques. La thèse explore alors comment, en s’appuyant sur des données existantes, il est possible d’enrichir les analyses en intégrant les capacités d’innovation des entreprises et les promesses de retours sur des produits encore à concevoir. Sont alors discutés à la fois les principes mais aussi les risques et les conditions d’un capital-régénération. Ce modèle, tout en expliquant une partie des difficultés des ETI à croître, ouvre des perspectives nouvelles sur les liens entre théorie financière et théories de la conception. / Private equity seems to play a key role in firms’ growth. However, the relationship between investment and growth remains poorly understood. Moreover, in recent years, doubts have arisen regarding the correlation between financial valuation and firms’ long-term and virtuous development - especially for mature firms. With a focus on French medium-sized companies (“ETI”), this thesis shows that a specific kind of private equity - that we propose to call “regeneration capital”- could be better conceptualized in order to support firms’ sustainable economic growth and to empower public policy with respect to corporate funding. Regeneration capital, unlike usual private equity asset class, is less related to the firm’s life cycle stage than to the nature of targeted growth. Rather than increasing the performance of existing products, this type of growth emerges from another growth dynamic, that we call “generative growth”, which results from the regeneration of the firm’s products and resources. Based on an analysis of the financial needs of medium-sized companies, as well as on an in-depth case study of medium-sized firms extracted from Bpifrance's investment portfolio, the thesis demonstrates that the growth shortage of medium-sized firms is not due to an equity gap. Empirical evidence rather suggests a lack of valuation of generative growth by traditional investment models. Drawing on existing data, the thesis hence investigates how investors’ financial analysis can be enhanced by integrating an assessment of firms’ innovation capabilities and of the return promises of yet unknown product to be developed. We then discuss the principles but also the risks and prerequisites of regeneration capital. This model not only explains part of medium-sized firms’ difficulties to grow but opens new perspectives on the relationship between corporate finance and design theories.