Chapter 2 demonstrates how individual income tax structures incentivize a more coordinated labour supply response to childbirth within married households: a joint selection out of the wage-paying sector and into self-employment. In a parallel analysis of longitudinal administrative and survey data from Canada, I show that the birth of a first child is associated with an increase in both maternal and paternal self-employment in married households; explained largely by an increase in co-employment. I develop a novel simulated instrument research design, which exploits exogenous tax variation, to show that this strategic re-organization of the household is partly incentivized by income splitting tax savings. Finding a reduced form elasticity of 0.5, these savings can account for half the increase in co-employment after childbirth. Beyond tax avoidance, this paper presents income splitting as a subsidy to the creation of flexible, tax-optimizing family firms that provide stable, long-run employment to households. Chapter 3 provides the first causal evidence on the impact of incorporation on the labour supply and hiring practices of self-employed professionals. It exploits staggered reforms across professions in each province to permit the registration of professional corporations in Canada. I found no evidence of a labour supply response to the significant tax implications of incorporation. However, for female professionals, incorporation increases the likelihood of hiring at least one employee. This result is consistent with the cash flow benefits of retained corporate earnings that enable to business owners to ensure against uncertain revenue. Chapter 4 extends the DiNardo, Fortin, and Lemieux (1996) study of the links between labour market institutions and wage inequality in the United States and updates the analysis to the 1979 to 2017 period. A notable extension quantifies the magnitude and distributional impact of spillover effects linked to minimum wages and the threat effects of unionization. A distribution regression framework is used to estimate both types of spillover effects. Accounting for spillover effects doubles the contribution of de-unionization to the increase in male wage inequality. It raises the explanatory power of declining minimum wages to two-thirds of the increase in inequality at the bottom end of the female wage distribution.