John Bogle and the triumph of modern portfolio theory

The recent death of John Bogle, founder of Vanguard and one of the great disruptors of the asset management industry, offers a timely reminder of the triumph of modern portfolio theory. The rise of low cost indexing would eventually tilt the playing field against corporate diversification in favour of financial diversification. The post also highlights the agency problems of index funds. Due to the free rider problem, index funds face particularly weak incentives to engage in stewardship activities that enhance corporate governance and market value. Founder companies potentially offer a resolution to these agency problems because many founders are poorly diversified financially and/or emotionally.