INTELLIGENCE REPORT SERIES MAY 2026 OPEN ACCESS

SERIES: ECONOMIC INTELLIGENCE

Top 0.1% at 13.8% — How Wealth Locks In (2026 Data)

In 2024 the 19 wealthiest US households gained more than the top 0.00001% gained in the previous four decades combined. The second phase begins.

Reading Time37 min
Word Count7,205
Published20 May 2026
Evidence Tier Key → ✓ Established Fact ◈ Strong Evidence ⚖ Contested ✕ Misinformation ? Unknown
Contents
37 MIN READ
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In 2024 the 19 wealthiest US households gained more than the top 0.00001% gained in the previous four decades combined. The second phase begins.

01

The Hinge Year
Why 2024 was the wealth concentration inflection

Wealth inequality has been measured for a century. ✓ Established What changed in 2024 is the rate at which the very top is pulling away from everyone else. The 19 wealthiest American households gained more share of national wealth in twelve months than the entire top 0.00001% gained in the previous four decades combined [7].

The Saez-Zucman distributional national accounts, updated in September 2024 and again with 2024 year-end data, show the top 0.1% of US households at a 13.8% share of national wealth — the highest single reading in their series [7]. That alone would be a headline. The accompanying detail is more startling: the 19 wealthiest households controlled 1.8% of total household wealth — roughly $2.6 trillion — at year-end 2024, up from 1.2% at the close of 2023 [7]. A 0.6 percentage-point gain in one year is larger than the cumulative gain this same fractile experienced between 1982 and 2023.

The pattern is not unique to the United States. The World Inequality Report 2026, edited by Lucas Chancel, Thomas Piketty and colleagues, finds that the global top 1% captured 41% of all new wealth created between 2000 and 2024 [2]. The bottom half of humanity received 1% of that incremental wealth. UBS's 2025 Global Wealth Report finds that the 60 million adults with at least one million dollars in net assets — 1.6% of the world's adults — now own 48.1% of total household wealth, while the 1.55 billion adults at the bottom share less than 1% [1].

13.8%
Share of US wealth held by the top 0.1% at end-2024 — a record high
Piketty-Saez-Zucman, 2024 · ◈ Strong
$124T
Wealth scheduled to pass between US generations, 2024–2048
Cerulli Associates, December 2024 · ✓ Established
281×
CEO-to-typical-worker pay ratio at top-350 US firms in 2024 (21× in 1965)
Economic Policy Institute, September 2025 · ✓ Established
51%
US adults in middle-income households in 2023, down from 61% in 1971
Pew Research Center, May 2024 · ✓ Established

The framing of inequality as a slow, century-scale phenomenon has shaped political response for a generation. The 2024 data require a different metaphor. A 0.6 percentage-point one-year move in the share held by 19 households is, by historical standards, a phase transition rather than a trend continuation [7]. ◈ Strong Evidence Oxfam's 2026 tracker estimates that global billionaire wealth rose 16% in 2025 to $18.3 trillion — three times the five-year average — adding $2.5 trillion in twelve months, roughly equivalent to the combined wealth of the world's poorest 4.1 billion people [14].

What distinguishes the second phase from the first is the lock-in mechanism. The first phase, running roughly from the early 1980s deregulation through the 2008 crash and the post-COVID monetary expansion, concentrated wealth in living individuals. The second phase begins when that concentration becomes hereditary. Cerulli Associates, the wealth-industry's standard data provider, estimates that $124 trillion will transfer between generations in the United States alone between 2024 and 2048, with $105 trillion flowing to heirs and $18 trillion to charity [4]. Roughly $62 trillion of that flow — more than half — originates with the 2% of households at the top.

Three structural changes converged to produce the inflection. Long-duration assets — equities, housing, private equity — appreciated in nominal terms by margins unattained in any decade since the 1920s. Labour's share of national income continued the slow decline first documented by Piketty and Saez in the 2000s, with median real wages growing one-third as fast as wages at the top decile across the OECD [10]. And the demographic mechanics of the Baby Boomer cohort entered their distribution phase: the people who accumulated the post-war asset stock are now dying or transferring it. The combination of high asset valuations, low labour share, and intergenerational transfer is what economists in the Piketty tradition predicted under r > g conditions. ◈ Strong Evidence It is now visible in the data.

A Phase Transition, Not a Trend

The 0.6 percentage-point one-year gain in the share held by the top 19 households is larger than the cumulative gain of the same fractile over the previous four decades. Inequality is no longer a gradient — it is a discontinuity. Political and tax systems calibrated for slow change are now responding to fast change with old instruments.

This report audits the second phase across six dimensions: the K-shaped consumption divide, the demographic disappearance of the middle class, the property border between owners and renters, the $124 trillion inheritance pipeline, the unresolved methodological war between Piketty-Saez-Zucman and Auten-Splinter, the historical pattern that produced the Great Compression of 1945–1980, and the narrow policy window now being tested by Brazil's G20 billionaire-tax initiative and the OECD's Pillar Two minimum corporate tax. The evidence is voluminous and, in places, genuinely contested. The conclusion is not.

02

The K Diagrammed
Asset owners and wage earners as two economies

The K-shape was coined in 2020 to describe a post-COVID recovery in which asset prices and wages diverged. Five years later the K has become structural: the post-tax income ratio between America's richest and poorest deciles rose from 8.6 to 9.9 between 2009 and 2024, and the top 10% now accounts for roughly half of all consumer spending [5].

Macroeconomists at the Minneapolis Federal Reserve, reviewing the K-shape literature in early 2026, concluded that the asymmetric recovery first observed in 2020 has hardened into a permanent feature of the US consumer economy [5]. The top decile's share of consumer spending — historically around one-third — has risen to approximately half. The implication is that aggregate demand statistics now describe two economies in a trench coat. When the top decile spends, headline GDP looks healthy. When the bottom 90% retrenches, retail and services data weaken even as the macro picture appears strong.

The mechanism is asset versus wage. ◈ Strong Evidence Households in the top decile derive a majority of their wealth gains from equity, business equity, and investment property; households in the bottom half derive their income almost entirely from wages and transfers [8]. When equity markets rise 25% in a year, top-decile households see direct wealth gains in the hundreds of thousands of dollars; bottom-half households see none, because they own no equities. Federal Reserve Survey of Consumer Finances data show that the top 1% holds less than 7% of its wealth in primary residences, while middle-class households hold roughly 60% in housing [8].

◈ Strong Evidence The K-shape is now a permanent structural feature of the US consumer economy, not a post-COVID anomaly

Reviewing US data through 2025, the Federal Reserve Bank of Minneapolis found that the post-tax income ratio between the top and bottom deciles rose from 8.6 in 2009 to 9.9 in 2024 — a 14% widening over fifteen years [5]. The top decile of households now accounts for approximately 50% of all US consumer spending, up from roughly one-third historically. The K-shape, originally coined as a pandemic-recovery metaphor, has hardened into a description of two distinct demand economies operating within a single GDP statistic.

The CEO pay channel reinforces the divergence. The Economic Policy Institute's annual audit found that in 2024 the average realized compensation of CEOs at the 350 largest US firms was $22.98 million — 281 times the pay of a typical worker at those companies and 1,094% higher than equivalent 1978 compensation in inflation-adjusted terms [6]. Typical-worker pay over the same 46 years rose 26%. Roughly 79% of CEO compensation now comes from stock-related instruments, meaning executive pay tracks asset prices rather than firm performance in any operational sense [6].

The K is visible in housing wealth as well. Urban Institute analysis of Federal Reserve data found that median homeowner housing wealth rose 44% between 2019 and 2022, reaching $200,000, while the renter share of cost-burdened households (those spending more than 30% of income on rent) reached an all-time high [11]. ✓ Established For Americans born after 1990, the asset/wage divide and the owner/renter divide are largely the same divide. Only 26.1% of Gen Z adults and 54.9% of millennials owned a home in 2024 [11].

The K appears in international data too. The Resolution Foundation's November 2024 audit found that in Britain the absolute wealth gap between the top and bottom deciles has widened to more than £1.2 million per household [15]. Strikingly, UK 60-somethings' median wealth fell 16% between 2018 and Q3 2024 — from £470,000 to £390,000 — while UK 30-somethings' median wealth rose 17%, partly the result of catastrophic property-price falls and partly the result of inheritance flows beginning to land. The K is generational as well as economic.

What the K disguises is the underlying economic reality of how aggregate demand is now constituted. When Moody's Analytics estimated in 2025 that the top 10% of US earners drove 49.7% of consumer spending, it was reporting a macroeconomic fact with political consequences: the bottom 90% of the country exerts decreasing leverage on aggregate demand and therefore on producers, who increasingly cater to the top decile. Luxury retail, premium real estate, second homes, and concierge medicine boom; mass-market retail and lower-cost services stagnate. ◈ Strong Evidence The diversification of consumption that built the post-war middle class is being reversed.

Two Economies, One Currency

When the top decile drives half of consumer spending, the relationship between wages and aggregate demand weakens. Firms increasingly cater to the asset-rich tier, because that is where the marginal dollar lives. This is the demand-side mechanism by which inequality reproduces itself: production reorients toward the buyers who exist, deepening the pattern.

03

The Vanishing Middle
Pew, OECD, and the demographics of disappearance

The middle class is not simply earning less — it is demographically shrinking. ✓ Established Pew Research Center finds that the share of Americans living in middle-income households fell from 61% in 1971 to 51% in 2023, while the OECD's standard "60-200% of median income" definition shows a comparable decline across advanced economies [3][10].

Pew's May 2024 audit of the American middle class is, by some distance, the most rigorous longitudinal measure in existence. Using a consistent definition — households earning between two-thirds and twice the national median income, adjusted for household size — Pew finds that the middle-class share of adults fell from 61% in 1971 to 51% in 2023 [3]. The lower-income share rose from 27% to 30%; the upper-income share rose from 11% to 19%. The middle class lost ten percentage points; the upper-income tier gained eight; the lower-income tier gained three.

The aggregate income story is sharper still. The middle class's share of total US household income fell from 62% in 1970 to 43% in 2022, while the upper-income tier's share rose from 29% to 48% [3]. By the standard arithmetic of distributive accounting, this is a generational migration of disposable income from the middle to the top. It happened slowly enough that it required two generations to become visible, but fast enough that no single year's data ever produced a political crisis. ◈ Strong Evidence The slow-motion character of the migration is itself a political fact.

✓ Established Fact The US middle class lost both demographic share and aggregate income share continuously from 1971 to 2023

Pew Research Center's longitudinal series finds the middle-income share of US adults declined from 61% in 1971 to 51% in 2023, while the middle class's share of aggregate household income fell from 62% (1970) to 43% (2022). Over the same period the upper-income tier's share of aggregate income rose from 29% to 48% [3]. The lower-income tier's share rose modestly (10% to 8%). The dominant flow was upward.

The OECD's Under Pressure: The Squeezed Middle Class report (2019) found a parallel pattern across 36 advanced economies. The OECD-wide middle-class share fell from 64% of the population in the mid-1980s to 61% by the mid-2010s [10]. One in five middle-class households now spends more than it earns. Middle-income wages across the OECD grew one-third as fast as wages at the top decile. Housing absorbs roughly one-third of middle-class disposable income today, up from one-quarter in the 1990s [10]. The macroeconomic conditions of a middle-class life — stable employment, affordable shelter, pension accumulation, occasional discretionary spending — have all become marginally more difficult to attain.

The geographic distribution of the squeeze is uneven. In Sweden, Finland, Denmark and the Netherlands the middle-class share has remained above 65%, supported by strong labour-market institutions and progressive transfers. In the United States, Israel and Chile the share has fallen toward and below 50%. The OECD's correlation with wealth distribution is striking: countries with thicker middle classes also have higher absolute wealth at the median, higher trust in institutions, and lower reported political polarisation. The relationship is not deterministic but it is robust.

Japan presents the analytically most interesting case. Japanese wealth Gini coefficients have risen since the mid-1990s, but the country's reported "middle-class" identification has held in survey data at roughly 90% — a level no other OECD economy approaches. The gap between objective inequality measures and subjective class identification has prompted the Japanese statistical office to begin a multi-year review. The likeliest explanation, in Japanese sociology, is that the middle-class identification reflects work tenure, housing security and educational credentials rather than current income. Whether that distinction remains durable as Japan's wealth distribution continues to skew is the open question.

What unifies the Pew and OECD findings is that the middle class is not simply earning less in real terms — it is becoming a smaller cohort. ◈ Strong Evidence A society in which 51% of adults are middle-income is a different society from one in which 61% are. The political coalition that supports public schools, mass-transit, public health and progressive taxation has historically been the middle 60% of the income distribution. When that coalition shrinks to 51%, the political mathematics of social provision change. Welfare states built for a 60%+ middle class begin to face structural revenue and political-economy strain, even if formal institutions remain unchanged.

The middle class is the backbone of our economies and societies. But there are signs that this bedrock of our prosperity is not as stable as in the past. The middle class has shrunk in most OECD countries because middle incomes grew less than the average and less than upper incomes.

— Angel Gurría, OECD Secretary-General, on the release of Under Pressure: The Squeezed Middle Class, April 2019
04

The Property Floor
How housing became the border of two classes

The single sharpest economic distinction in advanced economies today is not income — it is whether the household owns its dwelling. ◈ Strong Evidence The wealth gap between US homeowners and renters reached a historic high in 2022, and the median age of first-time buyers in the United States hit 40 in 2025 — the oldest on record [11].

The Urban Institute's analysis of the Federal Reserve's 2022 Survey of Consumer Finances quantified what every renter under 40 already knew: between 2019 and 2022, median homeowner housing wealth in the United States rose 44%, reaching $200,000 [11]. Over the same three years, the share of renter households spending more than 30% of income on rent reached a record. Federal Reserve data show that median net worth among homeowner households was $396,200 in 2022, against $10,400 for renter households — a roughly 38-to-1 ratio [8].

The generational pattern is unambiguous. Only 26.1% of Gen Z adults — those aged 18 to 27 in 2024 — owned a home, against 54.9% of millennials and 71.7% of Generation X at equivalent points in the lifecycle [11]. The median age of first-time homebuyers in the United States rose to 40 in 2025, the oldest on record and seven years older than the 33 of the mid-1980s [11]. The aggregate effect is that the wealth accumulation pathway that defined the post-war middle class — buy a starter home in one's twenties, accumulate equity over thirty years, retire with a paid-off house and Social Security — has become a minority experience for Americans born after 1990.

◈ Strong Evidence Housing is the single largest determinant of the K-shape and the most generationally regressive component of wealth accumulation

Middle-class US households hold roughly 60% of their wealth in their primary residence, against 7% for the top 1% [8]. When housing prices rise, middle-class balance sheets benefit only if the household already owns. The 44% rise in median homeowner housing wealth between 2019 and 2022 redistributed wealth toward existing owners and away from prospective buyers — a one-time intergenerational transfer hidden inside a market price movement [11].

The mechanism is more punishing than it appears. ◈ Strong Evidence Housing is not merely a wealth asset; it is the largest line item in the budgets of those who do not own. The OECD reports that middle-class housing costs across member economies now absorb approximately one-third of disposable income, up from one-quarter in the 1990s [10]. The proportion is higher in major metropolitan areas: in London, Sydney, Toronto and the major US coastal cities, median renter households spend 40–50% of gross income on rent. The arithmetic is direct: a renter household spending 40% of income on rent saves at roughly one-third the rate of an owner household with a paid-down mortgage. Over thirty years, this differential alone accounts for hundreds of thousands of dollars in lifetime wealth divergence, before any change in property values.

UK data underline the generational dimension. Resolution Foundation analysis of the Office for National Statistics' Wealth and Assets Survey found that the median wealth of UK 60-somethings fell 16% between 2018 and 2024 — from £470,000 to £390,000 — while UK 30-somethings' median wealth rose 17% over the same period [15]. The pattern is partly the result of falling absolute house prices in the south of England between 2022 and 2024, partly the result of accelerating inheritance receipts as the parents of late-millennials begin to die. The K has a generational arc that is just beginning to flip — for those with parents who own.

The international comparison is instructive. Germany's homeownership rate is 50% — the lowest in Western Europe — supported by a mature regulated rental market that produces tenure security at sub-market rents. The German Mietpreisbremse (rent brake) and the long-standing institution of indefinite leases mean German renters experience housing as a relatively stable cost rather than an asset they have failed to acquire. Compared to the Anglo-American model, German wealth inequality is comparable but the felt experience of inequality differs markedly. The lesson is that "ownership" and "tenure security" are separable: a renter with a thirty-year lease at predictable cost is in a different economic situation from a renter with a one-year lease and a 10% annual rent review.

The property border explains a feature of contemporary politics that puzzles many observers: the strong correlation between homeownership and political preference for incumbent parties, asset-protection policies, and restrictive zoning. Homeowners in the OECD have rationally organised to defend the value of their largest asset. ⚖ Contested The political economy literature attributes the housing supply restrictions of Anglo-American cities — and the resulting price escalation — to this defensive coalition, though the causal claim remains contested by housing economists who emphasise broader supply-and-demand fundamentals.

The Lifetime Differential

A renter household spending 40% of income on rent saves at roughly one-third the rate of a comparable owner household with a paid-down mortgage. Over thirty years, this single differential — independent of any change in house prices — produces hundreds of thousands of dollars of wealth divergence. The K-shape, in practice, is largely built out of rent.

05

The Great Wealth Transfer
$124 trillion and the coming inheritocracy

Between 2024 and 2048, an estimated $124 trillion will pass between generations in the United States alone. ✓ Established Roughly half of that flow — $62 trillion — will originate with the 2% of households at the top, meaning the dominant economic event of the next quarter-century is a one-time consolidation of inherited capital [4].

Cerulli Associates, the wealth-industry's principal data provider, publishes the most rigorously updated estimate of the US intergenerational wealth transfer. The December 2024 release puts the figure at $124 trillion to be transferred between 2024 and 2048: $105 trillion to heirs and $18 trillion to charity [4]. The figure has been revised upward six times since Cerulli first published a $59 trillion estimate in 2017 — each revision reflecting both asset-price appreciation and the addition of cohorts that were not previously dying in measurable numbers.

The distributional structure of the transfer matters more than the total. Cerulli's data show that 81% of the transferred wealth — approximately $100 trillion — comes from Baby Boomers and the smaller cohort above them. More than half — $62 trillion — comes from high-net-worth and ultra-high-net-worth households, defined as those with at least $5 million in investable assets. These households constitute roughly 2% of the US population. The arithmetic is direct: the dominant inheritance flow of the next quarter-century is a transfer from the top 2% of the older generation to a similarly concentrated cohort of younger heirs [4].

◈ Strong Evidence The $124 trillion intergenerational transfer is the largest hereditary wealth concentration event in modern history

Cerulli Associates estimates $124 trillion will transfer between generations in the United States from 2024 to 2048 [4]. By comparison, the entire global GDP in 2024 was approximately $110 trillion. More than half the flow ($62T) originates with the 2% of households at the top. The transfer is occurring in a tax environment in which the US federal estate-tax exemption is $13.99 million per person in 2025 — meaning the great majority of large estates pass without federal estate taxation [4].

The pattern echoes one Piketty and Zucman quantified for nineteenth-century France. Until 1910, inheritance accounted for 70–80% of new wealth in European economies. It collapsed to 30–40% during the 1950–1980 Great Compression, and has been climbing back since the 1980s to a current 50–60% — now rising. The 2024–2048 US transfer is the latest entry in a long historical sequence in which inheritance, suppressed for one or two generations after major shocks, returns as the dominant mechanism of wealth allocation. The mechanism is not new. The scale is.

The consequence is the consolidation of an inheritocracy — a society in which life outcomes are determined by what one's parents owned more than by what one does. The economist Branko Milanovic has measured this as the "homogeneity of capital and labour income," noting that since 2000 the United States has been the first advanced economy in which the same households appear in the top decile of both capital income and labour income. The Industrial Revolution's separation of capitalists from workers is being reversed: the top of the labour market and the top of the capital market are now the same people [2]. The middle class, which once provided most of both labour and consumer demand, is sandwiched between them.

The opportunity-mobility data corroborate. Raj Chetty's Opportunity Insights team has shown that the probability an American child earns more than their parents fell from approximately 90% for the 1940 birth cohort to 50% for the 1980s cohort [13]. Chetty has noted that the chance of achieving the American Dream — out-earning one's parents — is now almost two times higher in Canada than in the United States. The mobility decline is a direct mathematical consequence of slow median income growth combined with a heavy-tailed distribution: when the top is taking a larger share, fewer people at any given starting point can climb past their parents' standing.

Until 1910 the inheritance share was very high in Europe — 70 to 80 percent of total wealth was inherited. It fell abruptly following the 1914–1945 shocks, down to about 30 to 40 percent during 1950–1980, and is back to 50–60 percent — and rising — since 2010.

— Thomas Piketty & Gabriel Zucman, "Wealth and Inheritance in the Long Run," 2015

The political-economy consequence is what political scientists call the "lock-in" phase of the inequality cycle. Wealth that is hereditary tends to be politically self-protecting: inheritors form coalitions to preserve the tax and regulatory frameworks that maintain their position, and these coalitions are sticky because the wealth they defend is durable. The first phase of inequality — the build-up — can be reversed by progressive taxation, labour-market reform, and asset-price corrections. The second phase — the lock-in — is harder to unwind, because the assets and the political coalition reinforce each other. The closing window for reformist intervention, in the historical pattern, is the moment before the lock-in phase consolidates. ◈ Strong Evidence The 2024 data suggest that moment is approximately now.

The Inheritocracy Begins

$62 trillion of inherited capital flowing into the heirs of the top 2% over the next two decades will produce a generation of wealthy young adults whose position is determined by parental wealth, not market performance. The political coalition this creates will be more durable than the wealth itself.

06

The Methodological War
What Auten-Splinter and Piketty-Saez-Zucman actually disagree about

The most consequential academic dispute in inequality measurement turns on the treatment of untaxed business income, government transfers, and imputed consumption. ⚖ Contested Auten and Splinter find US top-1% income share approximately flat since the 1960s; Piketty, Saez and Zucman find it nearly doubled. Both teams use the same underlying tax data [7][9].

For two decades the Piketty-Saez series — the top-1% income share — has been the headline statistic of the inequality debate. It shows the US top-1% pre-tax income share rising from about 10% in 1980 to over 20% by the 2010s, the same level last reached in the late 1920s. Piketty's Capital in the Twenty-First Century (2014) built much of its argument on this series. In December 2023, Treasury economist Gerald Auten and Joint Committee on Taxation economist David Splinter published an alternative series that reached the opposite conclusion: once they had reallocated untaxed business income, government transfers, employer-provided health insurance, and imputed government services, they found the post-tax top-1% share approximately flat since the 1960s [9].

Piketty, Saez and Zucman replied in September 2024 with a 100-page technical document [7]. Their argument is methodological: they contend that the Auten-Splinter approach assumes a particular distribution of the untaxed components — government deficits, employer health insurance, untaxed Medicare benefits — that mechanically narrows the top-bottom gap. ⚖ Contested The dispute is not about the underlying tax data, which are shared. It is about who is assumed to receive the components that are not directly measured by the tax system.

Auten-Splinter: Stable Inequality

Top 1% share roughly flat since 1960s
Post-tax post-transfer top-1% share approximately constant at 8–10%, rising modestly to 11–12% recently.
Government transfers reduce the gap
Medicare, Medicaid, EITC and other transfers are assigned to bottom-half households, raising their measured income.
Underreported income is concentrated
Treasury research finds underreported business income concentrated at the top, but with patterns that suggest stability over time.
Imputed services matter
Employer-provided health insurance, public goods, and government services are imputed to recipients, raising bottom incomes.
Tax-unit methodology
The series uses tax units (rather than households) and adjusts for changes in family structure over time.

Piketty-Saez-Zucman: Rising Inequality

Top 1% share nearly doubled since 1980
Pre-tax top-1% income share rose from ~10% in 1980 to over 20% by 2010s.
Imputation assumptions are decisive
The Auten-Splinter approach assumes that untaxed components disproportionately benefit the bottom — an assumption that drives the entire result.
Wealth data corroborate income trends
SCF and estate-tax data show top-decile wealth share rising in parallel with the PSZ income series, suggesting the income trend is real.
The 19-household jump in 2024
The 0.6 pp one-year gain in the share held by the top 19 households cannot be explained by Auten-Splinter's flat-share thesis.
Untaxed corporate retained earnings
If retained earnings are assigned to shareholders, who are concentrated, top-share series rise. Auten-Splinter assign differently.

The most rigorous independent review of the dispute, conducted by the Washington Center for Equitable Growth in late 2024, concluded that both series capture real features of the data, but that the Auten-Splinter approach over-allocates imputed government consumption to the bottom of the distribution in ways that are not empirically justified. The Equitable Growth review found that, after correcting the most contested imputations, the top-1% income share has risen substantially since 1980 — though by less than the original Piketty-Saez headline figure. The consensus among inequality economists, as of late 2025, leans toward the PSZ approach but acknowledges that Auten-Splinter has narrowed — without overturning — the established picture.

◈ Strong Evidence The wealth-share series is less contested. Saez and Zucman's wealth estimates, which use capitalised income flows to estimate wealth holdings, are corroborated by the Federal Reserve's Survey of Consumer Finances, by Forbes' billionaire list, and by estate-tax filings. All three independent series show the top-decile wealth share rising from approximately 65% in 1980 to over 75% today [7][8]. The end-2024 reading of 13.8% for the top 0.1% is consistent across methods. The methodological war is mostly about income, not wealth — though the income debate has political importance because tax policy operates primarily on income.

The deeper question the dispute raises is what "inequality" measures. The Auten-Splinter view implicitly defines inequality as the post-tax post-transfer position of households, including imputed government services and employer-provided benefits. The PSZ view defines it as market-generated outcomes, with transfers and imputations measured separately. ⚖ Contested Both definitions are defensible. The political question — whether to celebrate or worry about current US inequality — depends partly on which definition one applies. The shared underlying fact is that pre-tax market inequality has risen dramatically and is being partially offset by transfer programs whose long-term political durability cannot be assumed.

The dispute matters operationally because policy is set against measurement. If inequality is roughly flat since 1980, the case for a billionaire tax weakens; if it has nearly doubled, the case is strong. The September 2024 PSZ reply was timed, not coincidentally, to coincide with the Brazilian G20 presidency's commissioning of the Zucman billionaire-tax blueprint. The technical academic dispute and the policy debate are running in parallel, with the technical disagreement being unusually sharp in part because the policy stakes are unusually high [12].

07

The Historical Frame
Gilded Age, Great Compression, Second Gilded Age

The current concentration episode is the second of its kind in measured economic history. ◈ Strong Evidence The first ran from approximately 1890 to 1929 and ended in the Great Compression of 1945–1980. The pattern, the mechanisms, and the eventual reversal are documented in the work of Goldin, Margo, Lindert and Piketty [2].

The first Gilded Age, dated by US economic historians from approximately 1890 to 1929, was a period in which industrial fortunes — Carnegie steel, Rockefeller oil, Vanderbilt railroads, Mellon banking — accumulated to levels that have no analogue in the post-war period until very recently. At its peak in 1928, the US top-1% income share reached approximately 24%, a level not reapproached until the late 2010s [2]. Wealth inequality moved in parallel: the top 1% held approximately 45% of US wealth in 1929, against a low of 22% by the mid-1970s.

The reversal was abrupt, fully documented, and is now understood as the Great Compression. Two periods of macro shock — 1914–1918 and 1939–1945 — destroyed inherited capital across Europe; the inter-war monetary instability and the 1929 crash erased large fortunes in the United States. The 1930s policy response, particularly the New Deal's expansion of the federal government and the 1942 introduction of wage controls by the National War Labor Board, set the institutional template that endured into the 1970s. Top marginal income tax rates exceeded 90% from 1944 to 1963 in the United States and remained at 70% until 1981. Inheritance taxes were materially higher than they are today. The middle class expanded both demographically and as a share of national income.

1890
US Gilded Age peaks — Carnegie, Rockefeller and Vanderbilt fortunes each approach 1.5% of GDP. Top-1% income share exceeds 18%.
1913
16th Amendment ratified — Federal income tax begins. Top marginal rate set at 7%. The legal infrastructure for redistribution is established.
1928
US top-1% income share peaks at 24% — Wall Street crashes one year later. The Gilded Age ends with the Depression.
1942
National War Labor Board imposes wage controls — The Great Compression (Goldin-Margo) begins. Top marginal tax rates exceed 90% from 1944.
1965
Post-war zenith — US CEO-to-worker pay ratio = 21:1. Middle-class share of US adults peaks above 60%. Top marginal tax rate still 70%.
1980
Reagan and Thatcher elected — The reversal begins. Top US marginal rate cut from 70% to 50% (1981) and 28% (1986). Financial deregulation accelerates.
2008
Global Financial Crisis — Federal Reserve balance-sheet expansion begins the modern asset-price era. QE inflates equity and housing values.
2014
Piketty publishes Capital in the Twenty-First Centuryr > g enters mainstream debate. The first comprehensive account of the second concentration.
2020
COVID crash and monetary response — Unprecedented fiscal and monetary intervention. The K-shaped recovery is diagnosed in real time.
2021
Pillar Two agreed — OECD/G20 ratify a 15% global minimum corporate tax. Implementation begins 2024 in EU and other adopters.
2024
Brazilian G20 commissions Zucman blueprint — Top-19 US household share jumps from 1.2% to 1.8% in one year. The second-phase inflection registers.
2026
World Inequality Report 2026 calls inequality "an emergency" — Global billionaire wealth reaches $18.3T. The political question becomes whether reformist intervention is still possible.

What distinguished the Great Compression was that it was driven by multiple forces simultaneously: capital destruction by war, regulatory expansion under the New Deal, the unionisation wave of 1935–1955 (which raised labour's share of national income), and a high-tax fiscal regime. None of these forces operated alone. The reversal beginning in 1980 was similarly multi-causal: financial deregulation, the decline of unionisation (US private-sector union density fell from 24% in 1973 to 6% in 2024), globalisation of capital but not labour, top-rate tax cuts in the Reagan and Bush administrations, and the rise of executive compensation tied to equity rather than performance.

The historical record provides two important warnings. ⚖ Contested First, the Great Compression was produced largely by external shocks — wars and depressions — not by deliberate policy alone. Whether a Great Compression can be produced in the absence of such shocks is the open question of contemporary political economy. Second, the lock-in phase that follows a concentration episode is historically more durable than the build-up phase. Once wealth becomes hereditary, the political coalition defending it is larger than the cohort that originally accumulated it. The window for reformist intervention narrows as the lock-in proceeds.

The historian Walter Scheidel, in The Great Leveler (2017), argued that all four historical mechanisms of large-scale inequality reversal — mass-mobilisation warfare, transformative revolution, state collapse, and catastrophic plague — were exogenous and violent. Scheidel's view is the pessimistic counterpoint to Piketty's call for democratic tax reform: he argues that the historical record contains no example of a major concentration of wealth being reversed by purely democratic means. ⚖ Contested Other historians, including Lindert and Williamson, dispute Scheidel's claim and point to the New Deal and the post-war social democracies as partial democratic levelings. The dispute is genuine and matters: it determines whether one views the present policy window as narrow but real, or essentially closed.

Either way, the precedent is sobering. The first Gilded Age produced 50 years of concentration before reversing. The second has now produced 45 years of concentration with no reversal yet visible. The 2024 data suggest the concentration is accelerating into its hereditary phase. The historical clock for reformist intervention is ticking against the lock-in. The next decade — roughly to 2035 — will determine whether the second concentration is ended by deliberate policy or by the kinds of catastrophic shock that ended the first.

08

The Policy Window
Zucman's 2%, Pillar Two, and the limits of national action

A 2% global minimum tax on the world's roughly 3,000 billionaires would raise $200–250 billion per year — a fraction of what they currently pay nothing on [12]. ◈ Strong Evidence Whether the political coalitions to enact such a tax exist before the lock-in phase consolidates is the central policy question of the next decade.

The most concrete contemporary policy response to the second concentration is the Brazilian G20 presidency's commissioning of Gabriel Zucman, in June 2024, to design a coordinated minimum effective tax on ultra-high-net-worth individuals. Zucman's blueprint, published as a G20 working paper, proposes a 2% annual minimum tax on the wealth of individuals holding more than $1 billion in assets. The estimated revenue is $200–250 billion per year on approximately 3,000 individuals. Extension to those with more than $100 million (approximately 90,000 individuals globally) would raise an additional $100–140 billion [12].

The arithmetic of Zucman's proposal is striking. Billionaires' current effective tax rate — measured as their total tax payments as a share of their wealth — averages approximately 0.3% globally. The 2% floor would raise that by a factor of roughly seven, but would still leave billionaires paying a smaller fraction of their wealth in tax than the average middle-class household pays in property tax alone. ⚖ Contested Critics, including the Auten-Splinter team, argue that measuring tax as a share of wealth rather than income is conceptually inappropriate: wealth is a stock, and tax is typically measured against the flows the stock generates. Zucman's response is that current tax systems systematically fail to capture the flows billionaires actually receive — primarily through unrealised capital gains and shielded business income — so a wealth-based minimum is necessary to restore a baseline contribution [12][9].

◈ Strong Evidence A coordinated 2% minimum tax on billionaires would raise $200–250 billion per year on approximately 3,000 individuals

Gabriel Zucman's June 2024 G20 blueprint estimates that a 2% annual minimum effective tax on individuals holding more than $1 billion would raise $200–250B per year [12]. Extending the floor to centimillionaires (~90,000 individuals globally) would add $100–140B. Current billionaire effective tax rates average ~0.3% of wealth — below the property-tax burden faced by typical middle-class homeowners.

The international precedent for Zucman's proposal is the OECD/G20 Pillar Two minimum corporate tax, agreed in October 2021 and beginning implementation in EU jurisdictions in 2024. Pillar Two imposes a 15% effective minimum tax rate on multinational corporate profits, regardless of where they are booked. Early estimates suggest it will raise approximately $200 billion per year in additional global revenue and substantially reduce profit-shifting to low-tax jurisdictions. The Pillar Two precedent is important politically because it demonstrates that internationally coordinated minimum taxes are feasible — the principal objection to wealth taxes (capital flight) is partially answered by coordination. Whether the same coordination can be achieved for individuals is the open question.

Norway, Spain and Switzerland already operate functioning wealth taxes at the national level. Norway's wealth tax raises approximately 1.1% of GDP from a tax rate of 1.1% on net wealth above NOK 1.7 million. Spain's "solidarity wealth tax" (2023) raised over €600 million in its first year from approximately 12,000 households. Switzerland's cantonal wealth taxes have operated continuously for over a century. These national experiences contradict the argument that wealth taxes are administratively infeasible. They do however illustrate that capital flight is real: Norway's 2022 tax-rate increase produced visible emigration of high-net-worth individuals to Switzerland, with the Norwegian Statistics Bureau documenting an outflow of approximately NOK 600 billion in declared wealth in the year following the rate increase. International coordination, in Zucman's framework, is what allows the wealth-tax-administration problem to be separated from the capital-flight problem.

RiskSeverityAssessment
Hereditary lock-in completes before reform window closes
Critical
$124T inheritance flow over 2024–2048 will produce a politically self-protecting heir class long before any reformist coalition consolidates.
Capital flight defeats unilateral wealth taxes
High
Norway and Spain experience documented HNW emigration after wealth-tax rate increases. International coordination (Zucman model) required to neutralise the risk.
Asset-price collapse erases middle-class wealth before policy responds
High
Middle-class wealth is 60% in housing; a major housing correction would crater middle-class balance sheets while leaving top-decile diversified portfolios largely intact.
Methodological dispute (Auten-Splinter vs PSZ) delays political action
Medium
Genuine academic uncertainty about the magnitude of income inequality is being used in policy debates to argue against intervention even where wealth data are unambiguous.
Mass-mobilisation moment (Scheidel scenario) replaces reformist path
Medium
Historical precedent suggests sustained concentrations of this magnitude reverse by violent shock rather than by deliberate policy. The political-stability cost of inaction is non-trivial.

The national-policy menu beyond wealth tax includes inheritance taxation (currently at historical lows in the United States, with a $13.99 million per-person federal exemption in 2025), labour-market reforms (raising the minimum wage and strengthening collective bargaining), housing-supply reform (zoning liberalisation, public-housing construction), and what Piketty has called "participatory socialism" — a combination of high progressive taxation, employee co-determination in corporate governance, and education-system reform aimed at reducing the inherited-credential premium. None of these is politically uncontroversial; all have functioning analogues in at least one major advanced economy.

◈ Strong Evidence The window for reformist intervention is narrowing but not closed. The Pillar Two precedent shows that international tax coordination is feasible. The Norwegian, Spanish and Swiss wealth taxes show that national wealth taxes function. The Brazilian G20 process has put a coordinated billionaire tax on the active multilateral agenda. The OECD's Under Pressure report, the World Inequality Report 2026, and Pew's middle-class audit have built a consensus measurement infrastructure that did not exist a generation ago. The economic and statistical preconditions for a Great Compression-style reversal are present.

What is uncertain is the political coalition. The middle class that produced the New Deal in the 1930s was 60%+ of the population and acted as a unified bloc on tax and labour-market policy. The middle class that exists today is 51% of the population, more demographically fragmented, and decreasingly identified with the labour-share interest that animated mid-twentieth-century redistribution politics. ⚖ Contested Whether a 51% middle class can produce the coalition that a 61% middle class produced is the central political question of the second concentration. The next decade will answer it. The historical alternative — Scheidel's catastrophic shock — is not one any rational political system should prefer.

Billionaires today pay a lower effective tax rate than the average middle-class worker. A 2% minimum tax on roughly 3,000 individuals would raise $200 to $250 billion a year — and would simply restore basic tax-system fairness.

— Gabriel Zucman, G20 report commissioned by the Brazilian presidency, June 2024
What the Evidence Tells Us

The second concentration is now visible in every measure: wealth shares, income shares, consumption shares, homeownership rates, intergenerational mobility, inheritance flows. The economic question is resolved. The political question — whether a 51% middle class can produce the New Deal coalition that a 61% middle class did — remains open. The 2024 inflection is the deadline.

SRC

Primary Sources

All factual claims in this report are sourced to specific, verifiable publications. Projections are clearly distinguished from empirical findings.

Cite This Report

APA
OsakaWire Intelligence. (2026, May 20). Top 0.1% at 13.8% — How Wealth Locks In (2026 Data). Retrieved from https://osakawire.com/en/wealth-inequality-second-phase-middle-class-disappears/
CHICAGO
OsakaWire Intelligence. "Top 0.1% at 13.8% — How Wealth Locks In (2026 Data)." OsakaWire. May 20, 2026. https://osakawire.com/en/wealth-inequality-second-phase-middle-class-disappears/
PLAIN
"Top 0.1% at 13.8% — How Wealth Locks In (2026 Data)" — OsakaWire Intelligence, 20 May 2026. osakawire.com/en/wealth-inequality-second-phase-middle-class-disappears/

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