A commodity cycle is an irregular sequence of expansion and contraction in a commodity market, most visibly expressed through price booms and slumps and often accompanied by changes in inventories, production, demand and investment. The word cycle does not imply a fixed or reliably repeating timetable. Turning points emerge from shocks and delayed responses whose timing and importance differ across commodities.
The delay is central to the mechanism. Strong demand or a supply disruption can tighten availability and raise prices faster than production capacity can respond. Higher prices may encourage additional output, investment, substitution or recycling, but mines, wells, processing capacity, acreage and other sources of supply can adjust on very different timescales. If new supply arrives after demand has cooled, the response that relieved scarcity can contribute to excess. Weak prices may then discourage investment or close high-cost capacity, reducing the buffer available against a later shock. Inventories can amplify or cushion this process, but an Inventory Cycle is not synonymous with the broader Commodity Cycle.
Several clocks can run at once
A Commodity Cycle can overlap with the Business Cycle without being identical to it. Industrial commodities are often sensitive to global economic activity, while agricultural markets can be dominated by weather and commodity-specific supply shocks. Longer investment responses may also sit on top of shorter macroeconomic fluctuations. A World Bank decomposition distinguished conventional 2–8-year business-cycle movements from 8–20-year medium-term movements associated with investment and found that the medium-term component explained roughly twice as much commodity-price variability on average as the business-cycle component. The mix nevertheless differed substantially across commodity groups, so the result is not a universal timing rule.
Cycle dating is method-dependent
Commodity price cycles do not have a single standardized dating convention. Researchers can identify different turning points depending on the price series, sample, frequency, inflation adjustment, filtering technique and rules used to qualify a movement as a cycle. One World Bank study published in 2025, for example, imposed a minimum 12-month phase, a minimum 36-month full cycle and a 15% amplitude threshold before classifying suitable price movements as cycles. Those parameters are research choices, not laws of commodity markets. Seasonality is different again: it describes tendencies linked to recurring calendar effects, whereas Commodity Cycle phases can have irregular lengths. For research, the useful question is therefore not simply “where are we in the cycle?” but which mechanism is producing the observed phase and what evidence would show that it is changing.