Trillions: How a Band of Wall Street Renegades Invented the Index Fund and Changed Finance Forever

Wigglesworth traces passive investing from the academic work that made it thinkable to the point where index funds and exchange-traded funds hold a substantial share of the world's equity. The chain runs through Bachelier and Samuelson on random walks, Markowitz on portfolio construction, Sharpe on the capital asset pricing model, Fama on efficient markets, and Wells Fargo's early institutional index accounts, before reaching Bogle's launch of the first retail index fund at Vanguard in 1976 and the creation of the first ETFs at the American Stock Exchange and State Street.

The book is reported history rather than argument. Wigglesworth interviewed most of the surviving participants and gives credit more accurately than the popular account does, showing that Bogle was a late convert and a marketer of an idea others had built, that John McQuown and Rex Sinquefield ran index money before Vanguard existed, and that Nathan Most designed the ETF wrapper for reasons that had little to do with retail investors.

The last section turns to consequences, and this is where it will interest investors most. Wigglesworth takes seriously the arguments that concentrated index ownership creates governance problems, that the big three managers now hold decisive voting power across the entire market, that common ownership may soften competition between rivals, and that ETF liquidity in credit markets is a promise that has never been tested in a real dislocation. He presents these as open questions rather than settling them, and he does not attempt a quantitative answer to the question of how much active management the market needs to stay efficient.