Capital in the Twenty-First Century

by Thomas Piketty

the eighteenth century, per capita income grew very slowly. In Great Britain, the average income was on the order of 30 pounds a year in the early 1800s, when Jane Austen wrote her novels.30 The same average income could have been observed in 1720 or 1770. Hence these were very stable reference points, with which Austen had grown up. She knew that to live comfortably and elegantly, secure proper transportation and clothing, eat well, and find amusement and a necessary minimum of domestic servants, one needed—by her lights—at least twenty to thirty times that much. The characters in her novels consider themselves free from need only if they dispose of incomes of 500 to 1,000 pounds a year.

Between 1913 and 1950, inflation in France exceeded 13 percent per year (so that prices rose by a factor of 100), and inflation in Germany was 17 percent per year (so that prices rose by a factor of more than 300). In Britain and the United States, which suffered less damage and less political destabilization from the two wars, the rate of inflation was significantly lower: barely 3 percent per year in the period 1913–1950. Yet this still means that prices were multiplied by three, following two centuries in which prices had barely moved at all. In all countries the shocks of the period 1914–1945 disrupted the monetary certitudes of the prewar world, not least because the inflationary process unleashed by war has never really ended.

this stage, I merely want to stress the fact that the loss of stable monetary reference points in the twentieth century marks a significant rupture with previous centuries, not only in the realms of economics and politics but also in regard to social, cultural, and literary matters. It is surely no accident that money—at least in the form of specific amounts—virtually disappeared from literature after the shocks of 1914–1945. Specific references to wealth and income were omnipresent in the literature of all countries before 1914; these references gradually dropped out of sight between 1914 and 1945 and never truly reemerged. This is true not only of European and American novels but also of the literature of other continents.

Capital is never quiet: it is always risk-oriented and entrepreneurial, at least at its inception, yet it always tends to transform itself into rents as it accumulates in large enough amounts—that is its vocation, its logical destination.

terms of asset structure, twenty-first-century capital has little in common with eighteenth-century capital. The evolutions we see are again quite close to what we find happening in Britain and France. To put it simply, we can see that over the very long run, agricultural land has gradually been replaced by buildings, business capital, and financial capital invested in firms and government organizations. Yet the overall value of capital, measured in years of national income, has not really changed.

To be sure, the distinction between public and private capital changes neither the total amount nor the composition of national capital, whose evolution I have just traced. Nevertheless, the division of property rights between the government and private individuals is of considerable political, economic, and social importance.

non-financial) is estimated to be almost one year’s national income in Britain and a little less than 1 1/2 times that amount in France. Since the public debt of both countries amounts to about one year’s national income, net public wealth (or capital) is close to zero. According to the most recent official estimates by the statistical services and central banks of both countries, Britain’s net public capital is almost exactly zero and France’s is slightly less than 30 percent of national income (or one-twentieth of total national capital: see Table 3.1).10 In other words, if the governments of both countries decided to sell off all their assets in order to immediately pay off their debts, nothing would be left in Britain and very little in France.

This historical record is fundamental for a number of reasons. First, it enables us to understand why nineteenth-century socialists, beginning with Marx, were so wary of public debt, which they saw—not without a certain perspicacity—as a tool of private capital.

the nineteenth century, lenders were handsomely reimbursed, thereby increasing private wealth; in the twentieth century, debt was drowned by inflation and repaid with money of decreasing value. In practice, this allowed deficits to be financed by those who had lent money to the state, and taxes did not have to be raised by an equivalent amount. This “progressive” view of public debt retains its hold on many minds today, even though inflation has long since declined to a rate not much above the nineteenth century’s, and the distributional effects are relatively obscure.

Only with the inflation of the 1950s (more than 4 percent a year) and above all of the 1970s (nearly 15 percent a year) did Britain’s debt fall to around 50 percent of GDP (see Figure 3.3). The mechanism of redistribution via inflation is extremely powerful, and it played a crucial historical role in both Britain and France in the twentieth century.

was in the late 1970s—a decade marked by a mix of inflation, rising unemployment, and relative economic stagnation (“stagflation”)—that a new consensus formed around the idea of low inflation. I will return to this issue later.

For example, when David Ricardo formulated in 1817 the hypothesis known today as “Ricardian equivalence,” according to which, under certain conditions, public debt has no effect on the accumulation of national capital, he was obviously strongly influenced by what he witnessed around him. At the moment he wrote, British public debt was close to 200 percent of GDP, yet it seemed not to have dried up the flow of private investment or the accumulation of capital. The much feared “crowding out” phenomenon had not occurred, and the increase in public debt seemed to have been financed by an increase in private saving. To be sure, it does not follow from this that Ricardian equivalence is a universal law, valid in all times and places. Everything of course depended on the prosperity of the social group involved (in Ricardo’s day, a minority of Britons with enough wealth to generate the additional savings required), on the rate of interest that was offered, and of course on confidence in the government. But it is a fact worth noting that Ricardo, who had no access to historical time series or measurements of the type indicated in Figure 3.3 but who had intimate knowledge of the British capitalism of his time, clearly recognized that Britain’s gigantic public debt had no apparent impact on national wealth and simply constituted a claim of one portion of the population on another.15

the case of public debt, representative agent models can lead to the conclusion that government debt is completely neutral, in regard not only to the total amount of national capital but also to the distribution of the fiscal burden. This radical reinterpretation of Ricardian equivalence, which was first proposed by the American economist Robert Barro,16 fails to take account of the fact that the bulk of the public debt is in practice owned by a minority of the population (as in nineteenth-century Britain but not only there), so that the debt is the vehicle of important internal redistributions when it is repaid as well as when it is not. In view of the high degree of concentration that has always been characteristic of the wealth distribution, to study these questions without asking about inequalities between social groups is in fact to say nothing about significant aspects of the subject and what is really at stake.

Furthermore, the fact that the Soviet Union joined the victorious Allies in World War II enhanced the prestige of the statist economic system the Bolsheviks had put in place. Had not that system allowed the Soviets to lead a notoriously backward country, which in 1917 had only just emerged from serfdom, on a forced march to industrialization? In 1942, Joseph Schumpeter believed that socialism would inevitably triumph over capitalism. In 1970, when Paul Samuelson published the eighth edition of his famous textbook, he was still predicting that the GDP of the Soviet Union might outstrip that of the United States sometime between 1990 and 2000.17 In France,

In the Belle Époque capital was king. In the years after World War II many people thought capitalism had been almost eradicated. Yet at the beginning of the twenty-first century Europe seems to be in the avant-garde of the new patrimonial capitalism, with private fortunes once again surpassing US levels. This is fairly well explained by the lower rate of economic and especially demographic growth in Europe compared with the United States, leading automatically to increased influence of wealth accumulated in the past, as we will see in Chapter

In other words, the United States is more than 95 percent American owned and less than 5 percent foreign owned.

Canada is thus more than 98 percent Canadian owned and less than 2 percent foreign owned.

What one finds is that the total market value of slaves represented nearly a year and a half of US national income in the late eighteenth century and the first half of the nineteenth century, which is roughly equal to the total value of farmland. If we include slaves along with other components of wealth, we find that total American wealth has remained relatively stable from the colonial era to the present, at around four and a half years of national income (see Figure 4.10

If one adds the market value of slaves to other components of wealth, the value of southern capital exceeds six years of the southern states’ income, or nearly as much as the total value of capital in Britain and France.

Over the long run, the nature of wealth was totally transformed: capital in the form of agricultural land was gradually replaced by industrial and financial capital and urban real estate. Yet the most striking fact was surely that in spite of these transformations, the total value of the capital stock, measured in years of national income—the ratio that measures the overall importance of capital in the economy and society—appears not to have changed very much over a very long period of time.

In the long run, the capital/income ratio β is related in a simple and transparent way to the savings rate s and the growth rate g according to the following formula: β = s / g For example, if s = 12% and g = 2%, then β = s / g = 600%.2 In other words, if a country saves 12 percent of its national income every year, and the rate of growth of its national income is 2 percent per year, then in the long run the capital/income ratio will be equal to 600 percent: the country will have accumulated capital worth six years of national income. This formula, which can be regarded as the second fundamental law of capitalism, reflects an obvious but important point: a country that saves a lot and grows slowly will over the long run accumulate an enormous stock of capital (relative to its income), which can in turn have a significant effect on the social structure and distribution of wealth.

Let me put it another way: in a quasi-stagnant society, wealth accumulated in the past will inevitably acquire disproportionate importance. The return to a structurally high capital/income ratio in the twenty-first century, close to the levels observed in the eighteenth and nineteenth centuries, can therefore be explained by the return to a slow-growth regime. Decreased growth—especially demographic growth—is thus responsible for capital’s comeback.

society twice as capital intensive as when the growth rate was 2 percent. In one respect, this is good news: capital is potentially useful to everyone, and provided that things are properly organized, everyone can benefit from it. In another respect, however, what this means is that the owners of capital—for a given distribution of wealth—potentially control a larger share of total economic resources. In any event, the economic, social, and political repercussions of such a change are considerable.

countries with similar growth rates of income per capita can end up with very different capital/income ratios simply because their demographic growth rates are not the same.

The first principle to bear in mind is, therefore, that the accumulation of wealth takes time: it will take several decades for the law β = s / g to become true. Now we can understand why it took so much time for the shocks of 1914–1945 to fade away, and why it is so important to take a very long historical view when studying these questions.

The most important factor in the long run is slower growth, especially demographic growth, which, together with a high rate of saving, automatically gives rise to a structural increase in the long-run capital/income ratio, owing to the law β = s / g.

But if one takes averages over longer periods, the fact is that all the rich countries are growing at approximately the same rate. Between 1970 and 2010, the average annual rate of growth of per capita national income ranged from 1.6 to 2.0 percent in the eight most developed countries and more often than not remained between 1.7 and 1.9 percent.

Turning now to average savings rates in the period 1970–2010, again one finds large variations between countries: the private savings rate generally ranges between 10 and 12 percent of national income, but it is as low as 7 to 8 percent in the United States and Britain and as high as 14–15 percent in Japan and Italy (see Table 5.1).

One particularly clear case is that of Japan: with a savings rate close to 15 percent a year and a growth rate barely above 2 percent, it is hardly surprising that Japan has over the long run accumulated a capital stock worth six to seven years of national income. This is an automatic consequence of the dynamic law of accumulation, β = s / g. Similarly, it is not surprising that the United States, which saves much less than Japan and is growing faster, has a significantly lower capital/income ratio.

The decline we see in the period 1910–1950 is consistent with low national savings and wartime destruction, and the fact that the capital/income ratio rose more rapidly between 1980 and 2010 than between 1950 and 1980 is well explained by the decrease in the growth rate between these two periods.

we need to add the fact that the price of real estate and stocks fell to historically low levels in the aftermath of World War II for any number of reasons

According to my estimates, this historical catch-up process is now complete: leaving aside erratic short-term price movements, the increase in asset prices between 1950 and 2010 seems broadly speaking to have compensated for the decline between 1910 and 1950.

The market value of the firm, that is, its stock market capitalization, may be significantly lower or higher, depending on whether financial markets have suddenly become more optimistic or pessimistic about the firm’s ability to use its investments to generate new business and profits. That is why, in practice, one always observes enormous variations in the ratio of the market value to the book value of individual firms.

If certain immaterial investments (such as expenditures to increase the value of a brand or for research and development) are not counted on the balance sheet, then it is logical for the market value to be structurally greater than the book value.

Leaving aside these interesting international variations, which reflect the fact that the price of capital always depends on national rules and institutions, one can note a general tendency for Tobin’s Q to increase in the rich countries since 1970. This is a consequence of the historic rebound of asset prices. All told, if we take account of both higher stock prices and higher real estate prices, we can say that the rebound in asset prices accounts for one-quarter to one-third of the increase in the ratio of national capital to national income in the rich countries between 1970 and 2010 (with large variations between countries).24

Broadly speaking, the 1970s and 1980s witnessed an extensive “financialization” of the global economy, which altered the structure of wealth in the sense that the total amount of financial assets and liabilities held by various sectors (households, corporations, government agencies) increased more rapidly than net wealth. In most countries, the total amount of financial assets and liabilities in the early 1970s did not exceed four to five years of national income. By 2010, this amount had increased to ten to fifteen years of national income (in the United States, Japan, Germany, and France in particular) and to twenty years of national income in Britain, which set an absolute historical record.28 This reflects the unprecedented development of cross-investments involving financial and nonfinancial corporations in the same country (and, in particular, a significant inflation of bank balance sheets, completely out of proportion with the growth of the banks’ own capital), as well as cross-investments between countries.

Here I have used the demographic and economic growth predictions presented in Chapter 2, according to which global output will gradually decline from the current 3 percent a year to just 1.5 percent in the second half of the twenty-first century. I also assume that the savings rate will stabilize at about 10 percent in the long run. With these assumptions, the dynamic law β = s / g implies that the global capital/income ratio will quite logically continue to rise and could approach 700 percent before the end of the twenty-first century, or approximately the level observed in Europe from the eighteenth century to the Belle Époque. In other words, by 2100, the entire planet could look like Europe at the turn of the twentieth century, at least in terms of capital intensity.

On the books of these individually owned firms, it is generally impossible to distinguish the remuneration of capital: for example, the profits of a radiologist remunerate both her labor and the equipment she uses, which can be costly. The same is true of the hotel owner or small farmer. We therefore say that the income of nonwage workers is “mixed,” because it combines income from labor with income from capital. This is also referred to as “entrepreneurial income.”

The reason is simple and was touched on earlier: the lion’s share of household wealth consists of “real assets” (that is, assets directly related to a real economic activity, such as a house or shares in a corporation, the price of which therefore evolves as the related activity evolves) rather than “nominal assets” (that is, assets whose value is fixed at a nominal initial value, such as a sum of money deposited in a checking or savings account or invested in a government bond that is not indexed to inflation).

Make no mistake: I am obviously not denying that inflation can in some cases have real effects on wealth, the return on wealth, and the distribution of wealth. The effect, however, is largely one of redistributing wealth among asset categories rather than a long-term structural effect. For example, I showed earlier that inflation played a central role in virtually wiping out the value of public debt in the rich countries in the wake of the two world wars. But when inflation remains high for a considerable period of time, investors will try to protect themselves by investing in real assets. There is every reason to believe that the largest fortunes are often those that are best indexed and most diversified over the long run, while smaller fortunes—typically checking or savings accounts—are the most seriously affected by inflation.

The case of an elasticity of substitution exactly equal to one corresponds to the so-called Cobb-Douglas production function, named for the economists Charles Cobb and Paul Douglas, who first proposed it in 1928. With a Cobb-Douglas production function, no matter what happens, and in particular no matter what quantities of capital and labor are available, the capital share of income is always equal to the fixed coefficient α, which can be taken as a purely technological parameter.17 For example, if α = 30 percent, then no matter what the capital/income ratio is, income from capital will account for 30 percent of national income (and income from labor for 70 percent). If the savings rate and growth rate are such that the long-term capital/income ratio β = s / g corresponds to six years of national income, then the rate of return on capital will be 5 percent, so that the capital share of income will be 30 percent. If the long-term capital stock is only three years of national income, then the return on capital will rise to 10 percent. And if the savings and growth rates are such that the capital stock represents ten years of national income, then the return on capital will fall to 3 percent. In all cases, the capital share of income will be 30 percent.

The point I want to emphasize, however, is that historical reality is more complex than the idea of a completely stable capital-labor split suggests. The Cobb-Douglas hypothesis is sometimes a good approximation for certain subperiods or sectors and, in any case, is a useful point of departure for further reflection. But this hypothesis does not satisfactorily explain the diversity of the historical patterns we observe over the long, short, or medium run, as the data I have collected show.

I begin by examining the inadequacy of the Cobb-Douglas model for studying evolutions over the very long run. Over a very long period of time, the elasticity of substitution between capital and labor seems to have been greater than one: an increase in the capital/income ratio β seems to have led to a slight increase in α, capital’s share of national income, and vice versa. Intuitively, this corresponds to a situation in which there are many different uses for capital in the long run.

I have just shown that an important characteristic of contemporary economies is the existence of many opportunities to substitute capital for labor. It is interesting that this was not at all the case in traditional economies based on agriculture, where capital existed mainly in the form of land. The available historical data suggest very clearly that the elasticity of substitution was significantly less than one in traditional agricultural societies.

elasticity of substitution of capital for labor is apparently greater than one. This is perhaps the most important lesson of this study thus far: modern technology still uses a great deal of capital, and even more important, because capital has many uses, one can accumulate enormous amounts of it without reducing its return to zero. Under these conditions, there is no reason why capital’s share must decrease over the very long run, even if technology changes in a way that is relatively favorable to labor.

The most important case, which I discussed briefly in the Introduction, is no doubt the increase in capital’s share of income during the early phases of the Industrial Revolution, from 1800 to 1860. In Britain, for which we have the most complete data, the available historical studies, in particular those of Robert Allen (who gave the name “Engels’ pause” to the long stagnation of wages), suggest that capital’s share increased by something like 10 percent of national income, from 35–40 percent in the late eighteenth and early nineteenth centuries to around 45–50 percent in the middle of the nineteenth century, when Marx wrote The Communist Manifesto and set to work on Capital.

the capital share was probably not very different around the turn of the twentieth century from what it was during the French Revolution and Napoleonic era

Recall that g measures the long-term structural growth rate, which is the sum of productivity growth and population growth. In Marx’s mind, as in the minds of all nineteenth- and early twentieth-century economists before Robert Solow did his work on growth in the 1950s, the very idea of structural growth, driven by permanent and durable growth of productivity, was not clearly identified or formulated.31 In those days, the implicit hypothesis was that growth of production, and especially of manufacturing output, was explained mainly by the accumulation of industrial capital. In other words, output increased solely because every worker was backed by more machinery and equipment and not because productivity as such (for a given quantity of labor and capital) increased. Today we know that long-term structural growth is possible only because of productivity growth. But this was not obvious in Marx’s time, owing to lack of historical perspective and good data.

Where there is no structural growth, and the productivity and population growth rate g is zero, we run up against a logical contradiction very close to what Marx described. If the savings rate s is positive, meaning the capitalists insist on accumulating more and more capital every year in order to increase their power and perpetuate their advantages or simply because their standard of living is already so high, then the capital/income ratio will increase indefinitely. More generally, if g is close to zero, the long-term capital/income ratio β = s / g tends toward infinity. And if β is extremely large, then the return on capital r must get smaller and smaller and closer and closer to zero, or else capital’s share of income, α = r × β, will ultimately devour all of national income.

The dynamic inconsistency that Marx pointed out thus corresponds to a real difficulty, from which the only logical exit is structural growth, which is the only way of balancing the process of capital accumulation (to a certain extent). Only permanent growth of productivity and population can compensate for the permanent addition of new units of capital, as the law β = s / g makes clear. Otherwise, capitalists do indeed dig their own grave: either they tear each other apart in a desperate attempt to combat the falling rate of profit (for instance, by waging war over the best colonial investments, as Germany and France did in the Moroccan crises of 1905 and 1911), or they force labor to accept a smaller and smaller share of national income, which ultimately leads to a proletarian revolution and general expropriation. In any event, capital is undermined by its internal contradictions.