ATCOR

The Theorem

ATCOR — All Taxes Come Out of Rent — is a theorem in Georgist economics associated particularly with Mason Gaffney. It holds that in a competitive economy, any tax levied on labour, capital, trade, or production ultimately reduces wages and returns to capital down to their marginal (opportunity cost) level, and the difference shows up as a reduction in land rent.

Put another way: because land rent is the residual surplus after all factors of production receive their market-clearing returns, taxes that reduce those returns ultimately show up as lower land rents. Under the theorem, the incidence of nearly every tax is, in the final analysis, land rent.

Implications

If ATCOR holds, it has a striking implication: taxing land rent directly is not simply more efficient than other taxes — it is the only tax base that does not distort the economy. All other taxes reduce output, employment, or investment compared to a counterfactual in which only land is taxed. The social cost of not adopting LVT is not merely the deadweight loss of existing taxes, but the full inefficiency of the current tax system — all of which, ATCOR implies, is ultimately borne by landowners anyway through lower rents.

Fred Harrison's Version

Fred Harrison's Ricardo's Law (2006) argues a closely related point: existing taxes on incomes and wages are "clawed back" by landowners through the rent mechanism. Workers who receive higher wages after a tax cut find that rising rents absorb the gain. This is not just a theoretical result but an empirically testable prediction about the incidence of tax cuts.

Relationship to Deadweight Loss

ATCOR is the stronger version of the standard efficiency argument for LVT. The standard argument holds that LVT has zero deadweight loss because the supply of land is inelastic. ATCOR adds that all other taxes create deadweight loss and that this loss ultimately falls on land rents — making the case for LVT not just efficiency-neutral but actively superior to all alternatives. The efficiency face of this claim has been quantified independently of Gaffney: Tideman, Akobundu, Johns & Wutthicharoen (2002) build a dynamic general-equilibrium model of the U.S. economy and estimate the avoidable excess burden from shifting five broad-based taxes onto land — a net welfare gain on the order of 14% of net domestic product in 2002, rising over time as the untaxed economy grows. Their companion proposition, that the deadweight loss itself comes out of rent, is developed on the EBCOR page.

Gaffney's "Negative Shifting" — the ATCOR Precursor

The term "ATCOR" does not appear in Gaffney's 1994 The Corruption of Economics, but the conceptual foundation is already present there. Gaffney describes what he calls "negative shifting" (Ch. 2): taxing land rent does not raise prices to consumers but instead lowers them, because the supply-side effects of taxing rent "will raise supplies of goods and services, and raise the demand for labor." Feder's postscript states the converse: "when these taxes are reduced, the primary result of tax un-shifting is an increase in the gross rent of land" (Gaffney & Harrison, The Corruption of Economics, 1994, Ch. 2, Postscript). See The Corruption of Economics (book page).

Dating correction (2026-07-16): this section previously stated the acronym itself was coined in the widely-cited 2005 working paper (WP096, "The Physiocratic Concept of ATCOR"). Reading Gaffney's 1998 book chapter, "The Philosophy of Public Finance" — Chapter 7 of Fred Harrison (ed.), The Losses of Nations (Othila Press, 1998) — found a section headed "4. The concept of ATCOR," closing "This is what is meant by the ATCOR concept: All Taxes Come Out of Rent," seven years before WP096. That 1998 chapter is now the earliest confirmed dated use of the named acronym; WP096 (2005) remains the fuller, freestanding statement of the argument and the primary citation for the theorem itself.

A still-earlier mechanism precursor (2026-07-18): Gaffney's 1970-71 AJES series "Tax-Induced Slow Turnover of Capital" derives, 24 years before the "negative shifting" language above, a formal version of the underlying mechanism: because land cannot legally be expensed (written off as a current cost) while capital investment can, universal expensing of capital investment "tends to convert the corporate income tax, which exempts wages, into a tax on land income" — the tax base left, once capital's return is fully sheltered, is land rent. This is narrower than the general ATCOR claim (Gaffney derives it specifically for capital-expensing under one tax, not as a theorem about all taxes shifting onto rent), so it is recorded here as an early precursor mechanism rather than an earlier statement of ATCOR itself or a change to the acronym's dating above.

Doucet's Modern Exposition

Lars Doucet provides the most accessible modern explanation of ATCOR in Land is a Big Deal (Ch. 15): any reduction in taxes on income and capital causes a proportionate increase in land rental values, because workers and investors bid up land prices with their after-tax gains. If ATCOR holds, a single-tax policy is self-financing — abolishing income and capital taxes shifts revenue to land rents, which 100% LVT then captures. Doucet cautions that ATCOR remains a hypothesis requiring empirical testing, not a proven theorem (Land is a Big Deal, Ch. 15). See Land is a Big Deal (book page).

Book Findings

Burgess: ATCOR from the Physiocratic Tradition

Ronald Burgess presents a version of the ATCOR argument in Public Revenue Without Taxation (1993), framed through the Physiocratic tradition. Burgess argues that "the Physiocrats rightly emphasised the true source of injustice to be the burden of taxation. General taxation, they argued, was a deviation from the 'natural order' which must result also in a contraction of future output" (Burgess 1993, Ch. 7, p. 75). This is the ATCOR logic stated from the Physiocratic side: taxes on production contract output, and the resulting reduction in economic activity ultimately reduces land rent — the converse being that removing taxes would raise rent. (C-claim; theoretical)

Burgess's formulation of the single-tax argument — that abolishing taxation and replacing it with land rent collection is "a prerequisite for solving the major social and economic problems, including inflation and unemployment" (Burgess 1993, Ch. 10, p. 109) — implicitly depends on an ATCOR-like mechanism: if taxes suppress production, their removal raises economic activity and thus land rent, making the transition self-financing. Burgess does not use the term "ATCOR" (coined by Gaffney in 2005) but the conceptual logic is present: taxation comes out of rent, so collecting rent directly is non-distortionary in a way that taxation is not. (D-claim; interpretive)

Caveats

ATCOR, like many claims in economic theory, depends on assumptions about market completeness and competitive conditions that may not hold in all real-world contexts. Critics argue that not every tax is fully shifted onto land rent, particularly in the short run or in internationally open economies. Gaffney and Harrison argue the mechanism operates over the medium-to-long term. The premise that the burden settles on land rent as a pure residual also has a direct mainstream theoretical challenger — Feldstein (1977), who argues that in a general-equilibrium growth model a tax on pure rent is "at least partly shifted" onto capital via a savings-portfolio channel (though that result is itself contested by Calvo-Kotlikoff-Rodriguez and Fane; see the linked page).

Gaffney invokes the term again, in passing, in his later 2016 essay on European tax policy — "Many of us now hew to the Physiocratic doctrine that All Taxes Come Out of Rents (ATCOR)" — but that essay's substantive argument is about VAT and sales-tax excess burden specifically, not a further development of the theorem itself; see Gaffney (2016), Europe's Fatal Affair with VAT for that argument, and the 2005 paper above for ATCOR's primary statement.

See Also

• Monaco — near-zero personal taxation fully capitalised into the world's highest land prices, an extreme real-world case of the ATCOR mechanism
• Gaffney (2005): The Physiocratic Concept of ATCOR — the fuller, freestanding working-paper statement of the thesis
• Gaffney (1998): The Philosophy of Public Finance — the book chapter now confirmed as the earliest dated use of the "ATCOR" name, with a formal algebraic derivation
• Gaffney (2016): Europe's Fatal Affair with VAT — a later essay that invokes ATCOR in passing while arguing the separate case against VAT
• EBCOR
• Land Value Tax
• Deadweight Loss — the efficiency argument
• Mason Gaffney — primary developer of ATCOR
• Fred Harrison — Ricardo's Law
• Economic Rent
• Public Revenue Without Taxation — Burgess on ATCOR from the Physiocratic tradition
• Tideman et al. (2002), The Avoidable Excess Burden of Broad-Based U.S. Taxes — independent CGE quantification of the efficiency gain
• Feldstein (1977), The Surprising Incidence of a Tax on Pure Rent — the mainstream challenge to the residual-incidence premise

Sources

1. Mason Gaffney — collected work on ATCOR and land's taxable capacity. Free archive — used for the general ATCOR framework and Gaffney's theoretical contributions to the concept.
2. Fred Harrison (2006), Ricardo's Law: House Prices and the Great Tax Clawback Scam. Share The Rents — used for the tax clawback mechanism and Harrison's version of ATCOR (§ "Fred Harrison's Version").
3. Related: The Hidden Taxable Capacity of Land — wiki summary — companion wiki page holding the quantified version of the claim (Gaffney 2009); see it for the figures.
4. Henry George (1886), Protection or Free Trade — wiki summary, used for George's own early statement of the logic later called ATCOR.
5. Mason Gaffney & Fred Harrison, The Corruption of Economics, Shepheard-Walwyn, 1994, Ch. 2 — used for "negative shifting" and the ATCOR precursor concept (A-claim). See The Corruption of Economics (book page).
6. Lars A. Doucet, Land is a Big Deal, Shack Simple Press, 2022, Ch. 15 — used for the modern exposition of ATCOR and the Single Tax self-financing argument (A-claim). See Land is a Big Deal (book page).
7. Ronald Burgess, Public Revenue Without Taxation (London: Shepheard-Walwyn, 1993) — used for the Physiocratic version of the ATCOR logic (C/D-claims). Book page
8. Mason Gaffney (1998), "The Philosophy of Public Finance," Ch. 7 in Fred Harrison (ed.), The Losses of Nations (Othila Press, 1998) — used for the dating correction on when the named acronym "ATCOR" is first attested (A-claim). Wiki summary