This thesis is a collection of four self-contained papers on topics related to labour economics and industrial organization. In the first part of the thesis, I study how different components of a welfare state, namely disability insurance (DI) and pensions, affect individual and household labour supply decisions. I show how the decision to work – and how much to work – is influenced by the incentives embedded in these schemes, which provides guidance on how to design them to increase efficiency and people’s well-being. In the second part of the thesis, instead, I study how the institutional features of a market can facilitate or hinder collusion between firms. I show that, in some cases, excessive market transparency makes collusion easier to sustain and ultimately lowers consumers’ welfare.