Top-end inequality and growth: empirical exploration of nonlinearities and the time dimension

Using the series of the top 1% income shares in 137 countries, I examine the relationship between top-end inequality and subsequent economic growth from the 1920s to the 2010s. These data enable a versatile exploration of various time horizons. To address concerns regarding chosen functional forms, I employ penalized spline methods to accommodate potential nonlinearities. Empirical findings suggest that the relationship between top-end inequality and subsequent growth is complex, contingent upon both the investigated time horizon and the level of economic development. I find some evidence for a positive link at medium levels of economic development, with this positive link being more pronounced in short- to medium-term associations. I also find that the positive medium-run association weakens as economic development advances. In advanced economies, a negative (or nonpositive) medium- to long-term relationship emerges between the top 1% income share and growth in many settings. Furthermore, I conclude that longer-run associations need to be investigated further.