This search for a model helping us understand how workers and firms are matched, with the associated optimal wage setting, is pursued in the fourth project in association with Philippe Choné. There, workers are endowed with multidimensional skills which cannot be unpacked – skills are said to be bundled – in the absence of skill-specific labor markets, in a world where firms a) differ in how they value each skill dimension in their production technology and differ in their productivity; b) aggregate their workers’ skills to produce; c) and optimally choose their size? Because bundling prevents workers from selling their skills separately, one by one, on skill-specific markets, the implicit price of each skill is shown to vary across firms, workers’ sorting into firms is shown to depend on their comparative advantage, and firms’ (unique) size is shown to increase in productivity. The (unique) equilibrium wage function is shown to be log-additive in worker quality and a “firm component” that reflects the firm’s aggregate skill-mix, the equilibrium matching, and, potentially, the firm’s productivity. Furthermore, we show that Generalists’ workers – endowed with a balanced set of skills – suffer from a wage markdown in a purely competitive framework (and, hence, no firm’s monopsony power). This setting is particularly helpful in understanding how firms and their workers are affected in today’s world in contrast to the recent past. More precisely, we study what happens when one of the k markets for skills opens, something we label “unbundling” starting from a bundled world. Unbundling may be due to technological shocks, such as the advent of Uber, that transforms a market (for taxi rides, in the case of Uber) or a legislative change, again opening a market for a skill, a task, that could not be exchanged and priced (such as some types of business services in Germany before the Hartz reforms) in the past because of bundling. In a modeling effort made in association with Nathael Gozlan, a mathematician, we fully characterize how the equilibrium changes when unbundling takes place, the firms and the workers who benefit from this opening and, by contrast, the firms and the workers who are harmed. To confront our theory with facts, Philippe Choné, myself, together with Oskar Nordström Skans, we currently assess the empirical support of this novel theory using Swedish data on workers’ Cognitive and Non-Cognitive skills, and their employers.