Capital in the Twenty-First Century

by Thomas Piketty

In particular, the return on agricultural land in traditional societies, like the return on real estate in today’s societies—these being the most common and least risky forms of investment in each case—is generally around 4–5 percent, with perhaps a slight downward trend over the very long run (to 3–4 percent rather than 4–5). The economic model generally used to explain this relative stability of the return on capital at around 4–5 percent (as well as the fact that it never falls below 2–3 percent) is based on the notion of “time preference” in favor of the present. In other words, economic actors are characterized by a rate of time preference (usually denoted θ) that measures how impatient they are and how they take the future into account.