How Should We Tax Wealth?
The Mathematician Who Wants to Tax Your Great-Grandchildren's Inheritance
Thomas Piketty spent years building one of the most controversial databases in modern economics, and what he found in it suggests that capitalism, left alone, doesn't spread wealth — it concentrates it, generation after generation, until democracy itself starts to buckle.
The Idea
Piketty's central argument, developed across his 2013 work Capital in the Twenty-First Century, is deceptively simple: when the return on capital — what your assets earn — consistently outpaces economic growth, wealth concentrates upward over time. He expressed this as r > g. It sounds technical, but the implication is almost mechanical: if your investment portfolio grows faster than the economy as a whole, the already-wealthy capture a rising share of everything, while wages, which are tied to growth, fall behind. The twist that makes this alarming rather than merely academic is the historical data. Piketty and his colleagues assembled centuries of tax records from France, the UK, and the US, and found that the mid-twentieth century — with its relatively compressed inequality — was the anomaly. The two World Wars and the Depression destroyed so much capital that wealth concentration briefly flattened. Without those catastrophes, the default trajectory of capitalism appears to be aristocracy. His proposed remedy is a progressive global wealth tax — not on income, but on net worth, including assets that are never sold and therefore never appear on an income tax return. A small annual levy on accumulated wealth, he argues, would slow the compounding engine that turns family fortunes into dynasties. Critics on the left think it doesn't go far enough; critics on the right think it is administratively naive and economically self-defeating. Almost everyone agrees it is genuinely radical.
In the World
Consider the Walton family, heirs to the retail empire built by Sam Walton, who died in 1992. In the three decades since, family members have collectively grown their inherited fortune to a figure larger than the GDP of many mid-sized nations — not primarily by working or innovating, but by holding equity in a company that kept appreciating. Sam Walton was a genuine entrepreneur; the third generation is, by and large, inheriting the returns on his capital. This is precisely the dynamic Piketty's data captures: wealth that compounds across generations, insulated from the erosion that wages and salaries face. Piketty's wealth tax would apply annually to this kind of accumulated net worth — the proposal in his 2020 follow-up, A Brief History of Equality, suggests rates that rise steeply with wealth, with revenues earmarked for a universal capital endowment: a lump sum paid to every citizen at adulthood. The political vision is to give everyone a stake in capital, not just those born into it. France briefly experimented with a wealth tax called the ISF before abolishing it in 2017, partly due to concerns about wealthy residents relocating. That episode became a favourite talking point for opponents — but Piketty's response is that a unilateral national tax and a coordinated global one are entirely different instruments, and conflating them is a deliberate misdirection.
Why It Matters
You don't need to accept Piketty's politics to find his core data unsettling. The question he forces onto the table is whether the rules governing wealth accumulation were ever designed with democratic fairness in mind — or whether they evolved to protect whoever happened to hold assets when the rules were written. Most people build their financial lives through earned income: salary, freelance work, a small business. These are taxed heavily, often at source. Meanwhile, the appreciation of a large stock portfolio or a property empire held for decades can compound largely untouched until the moment of sale — and in some jurisdictions, passed on at death with generous reliefs. Whether or not a global wealth tax is feasible, the asymmetry is real and worth sitting with. When you think about the financial choices available to you — saving, investing, building something — the background architecture of who gets taxed on what, and when, shapes the playing field you are operating on. Understanding that architecture is the first step to having a view on whether it is fair.
A Question to Ponder
If you inherited significant wealth tomorrow, would you feel that a recurring tax on it was more or less legitimate than the income tax you already pay on your work — and what does your instinctive answer reveal about how you think wealth should be earned?
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