If capital is the lifeblood of capitalism, then its overabundance is its cholesterol. For all the hand-wringing over scarcity, most investment busts are caused by excess: money poured hastily into sectors where previous profits were high, and future ones soon aren’t.
Consider the mining boom of the early 2000s. Following the dotcom crash, investors flushed with liquidity and starved of returns turned to metal. China, the world’s newest workshop, obliged. Between 2002 and 2008 commodity prices rocketed, doubling twice. Mining firms saw returns on capital jump from a modest 7.5% to a brawny 35%. What followed was predictable, if not preventable: a flood of investment, soaring output, new entrants (some reputable, others less so) and then—inevitably—collapse. By 2015 iron ore prices had plunged 70%. The machines were still humming but the margins had vanished.
This boom-bust cycle was no aberration. It was a textbook illustration of the capital cycle, a concept so old it feels new. When returns in a sector jump, capital rushes in, capacity expands, competition intensifies and profits erode. The more capital is deployed, the lower the return on capital becomes. Like an overwatered plant, the sector wilts not for lack of nutrients but from excess.
That makes intuitive sense. In a world of constrained demand, adding more supply—whether iron ore, electricity or boutique hotels—does not add proportionate value. Marginal productivity falls. At some point each additional dollar invested yields less than the last. This is not mere theory. It is how real-world capital allocation often works—and fails.
Take HydroCo, a fictional but painfully plausible hydropower developer. Riding the green energy wave, it expands rapidly, buoyed by subsidies, investor praise and climate credentials. Its CEO is no longer ignored at dinner parties (and his wife no longer finds him boring, to borrow from a capital-cycle primer). But as more HydroCos pile in, competition intensifies, demand plateaus and prices tank. Returns on capital dip below the cost of capital. What follows is familiar: restructuring, fire sales and a new round of solemn conference panels on “sustainable growth”.
The pattern is older than HydroCo, and cleverer than any spreadsheet. It reflects a broader economic truth: capital is a herd. Once a sector proves lucrative, investors stampede toward it, extrapolating past performance far into the future. And it is in this very act of copying success that they destroy it.
Behavioural economists have tried to explain this self-defeating logic. Daniel Kahneman, who won a Nobel prize for his troubles, coined the term “inside view”: our tendency to judge a decision based on immediate factors rather than wider patterns. Investors extrapolate from recent gains and underestimate competition. They also place blind faith in management projections. They anchor on today’s trends and forget yesterday’s lessons.
Even when the data screams caution, incentives say otherwise. CEOs are rewarded for growth not restraint. Investment bankers pocket fees on capital raised rather than capital returned. Fund managers chase quarterly gains not decade-long returns. The fallout is a system geared towards overcapitalisation, followed by disappointment and then eventually rebalancing. It resembles Schumpeter’s “creative destruction”, though with more PowerPoint and less poetry.
This cycle plays out across industries. In tech cheap money has fuelled hundreds of nearly indistinguishable startups. In real estate speculative overbuilding is followed by vacancies and rent corrections. In renewables well-meaning oversupply can produce grid congestion and falling power prices. Each cycle ends the same way: with sobered investors wondering why nobody saw it coming.
Not all investment is bad, of course. But investment without discipline is. The capital cycle does not argue against boldness: it cautions against blindness. A project that looks profitable at a 10% return may look far less so when five other firms build the same thing. Worse still, those returns may vanish long before the last cement dries.
So what can be done? Investors can start by watching capacity (and earnings). They can ask what a firm plans to build, but also what others are building. They can factor in time—the lag between capital commitment and project completion—during which market dynamics may change entirely. Above all, they can remember not every boom needs their money.
Capitalism’s strength is adaptability. But its Achilles heel is repetition. The laws of supply and demand may be inviolable, but human memory is not. That is why the real question is not whether capital will overreach—it will—but how many lessons must be relearned before it stops.
The answer is for now: probably one more. ■
