"The rise of the super-rich has attracted much political and academic attention in recent years. However, there have been few attempts to explain the cross-national along with the temporal variation in the rise of top incomes. Drawing on the World Wealth and Income Database, we study the income share of the top 1% in current postindustrial democracies from 1960 to 2012. We find that extreme income concentration at the top is a predominantly political phenomenon, not the result of increasing marginal productivity of top managers in markets of increasing size. Top income shares are largely unrelated to economic growth, increased knowledge-intensive production, export competitiveness, financialization and wealth accumulation, though they are related to stock market capitalization. Instead, they are closely associated with political and policy changes such as union density and centralization, secular-right governments, top marginal tax rates and investment in public tertiary education."

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