• globalisation
• technological change (information and communications technology)
• growth of financial services
• changing pay norms
• reduced role of trade unions
• scaling back of the redistributive tax-and-transfer policy

[...] we risk creating the impression that inequality is rising on account of forces outside our control. It is far from obvious that these factors are beyond our influence or that they are exogenous to the economic and social system. Globalisation is the result of decisions taken by international organisations, by national governments, by corporations, and by individuals as workers and consumers. The direction of technological change is the product of decisions by firms, researchers, and governments. The financial sector may have grown to meet the demands of an aeing population in need of financial instruments that provide for retirement, but the form it has taken and the regulation of the industry have been subject to political and economic choices.