Book Review — “Trillions” by Robin Wigglesworth

Many people walk around with a retirement account that quietly compounds in the background without ever asking who built the machine that makes it possible. Robin Wigglesworth’s 2021 book, Trillions: How a Band of Wall Street Renegades Invented the Index Fund and Changed Finance Forever, answers that question with an eye for the strange personalities who changed global finance without meaning to.

It is a narrative about rebels and misfits. It is also a narrative about how ideas that once sounded laughable became the backbone of the world’s savings industry.

When people praise the index fund today, they often credit Jack Bogle and stop there. Wigglesworth shows that the road to this invention was full of confusion, luck, missed opportunities, stubbornness, and peculiar characters whose brilliance was rarely recognised in their own lifetimes.

One of the earliest of these characters was Leonard “Jimmie” Savage. His work on statistical decision theory barely received attention while he was alive. Wigglesworth notes that it attracted only a scattering of interest in small mathematical circles. Yet those dusty ideas seeded the thinking that would eventually drive the creation of index investing. Many revolutions begin this way, with thinkers who are ignored until someone else realises the value of their strange ideas.

The book thrives on such stories. My favourite is Markowitz’s. Before becoming the father of Modern Portfolio Theory, he worked a regular job, read a book list recommended to him, and stumbled upon John Burr Williams’s classic. Williams had lived through the crash of 1929 and the Great Depression. He got so shaken by the chaos around him that he abandoned Wall Street and marched into Harvard for a PhD to understand what had happened. The instinct was simple. Better ideas would prevent the next disaster. Markowitz read the book, caught fire, and the world changed.

Another story shows how much of life bends to chance. Eugene Fama nearly missed out on attending the University of Chicago because the school misplaced his application. He phoned the office to ask why he had not heard back, and by some twist of fate the dean of students answered the line. That conversation led to a scholarship, which then led to a career that reshaped how we think about markets. Wigglesworth serves this anecdote with light humour and a reminder that persistence often tilts luck in our favour.

Jack Bogle receives the largest share of attention in the book. Wigglesworth respects him, but he does not romanticise him. Bogle was strong headed and visionary, but he had blind spots. When the pioneers of ETFs came knocking, he mocked the idea and dismissed it. He could not imagine index investing evolving beyond mutual funds. It is a humbling reminder that even the brightest thinkers have limits. No one sees the full arc of the future.

Larry Fink’s story is another high point. I had already encountered an excerpt of it online, which partly motivated me to pick up the book. Reading it in context, with Wigglesworth’s careful pacing, made it richer. You do not need to know anything about BlackRock to appreciate how Fink’s career rises, collapses, and rises again. Wigglesworth narrates it with the vividness of a novelist. The writing sparkles.

Throughout the book, you realise that the index fund is one of the few financial inventions that truly serves regular people. Wigglesworth writes that it is a rare exception to the rule, a product that lines the pockets of savers rather than bankers. You feel this deeply by the time you reach the final chapters. The industry has saved hundreds of billions in fees. Those savings will become trillions. Everyone saving for retirement, a house, a child’s education, or a rainy day benefits from the humble index fund.

To truly understand the scale of index funds and ETFs, you have to know that they now oversee more than $25 trillion globally. When Bogle launched the first index fund in 1976, it raised $11 million, which critics mocked as “Bogle’s Folly.” Today, Vanguard alone manages more than $8 trillion, and BlackRock’s iShares franchise controls another $3 trillion plus. Passive investing now accounts for over 50 percent of all money in US equity funds.

Yet the book is not a sales pitch. As an eternal evangelist of ETFs and an ardent preacher against active trading and the buying of individual stocks, this truly surprised me. Wigglesworth is frank about the flaws. He explains that indexing can distort capital allocation by rewarding companies for past size rather than future promise. He illustrates how ETFs can amplify market volatility. I found these sections refreshing. They elevate the book beyond hero worship.

The book is masterfully written. Financial Times journalist Robin Wigglesworth pieces the stories together with skill and turns complex financial history into a vivid journey. He never loses sight of the human element like stubbornness, brilliance, pettiness, and courage that shape the market we all rely on.

By the time you finish Trillions, your respect for index funds increases, but something else happens too. You see finance as a long chain of flawed humans doing their best to solve hard problems. Wigglesworth makes you feel grateful that some of their solutions work.

If you save, invest, plan for your future, or wonder why your pension exists in its current form, read this book. It is a story of quiet revolution. It is also an entertaining tribute to the outsiders who built the most powerful idea in modern finance.