Natural resources: risk, return, inflation hedging and diversification

How do the risks and returns compare?

Commodities, farmland and timberland differ first in how they are priced. Commodities trade second by second on public exchanges, so their price reflects the latest information. Farmland and timberland trade rarely, in private markets, so their values rest on infrequent transactions and appraisal-based pricing with imprecise estimates.

Natural resource investmentsdifferent pricing, drivers and risks

• Commodities Memorize priced continuously on exchanges; high return and very high volatility
  • Return drivers Use it supply and demand, global growth, inventories
  • Key risks Use it demand shocks, geopolitics, weather, leverage in futures strategies
  • Supply response Memorize slow: production lead times
• Farmland Memorize priced by infrequent appraisals; low reported volatility
  • Return drivers Use it crop prices, yields, land values
  • Key risks Memorize weather, disease, global trade and competition, illiquidity, high fixed costs
• Timberland Memorize priced by infrequent appraisals; low reported volatility
  • Return drivers Use it biological growth, lumber prices, land values
  • Key risks Memorize weather, fire, pests, global trade, illiquidity
• Raw land Know the idea riskiest land type: no income, depends on future use

	Commodities	Farmland and timberland
Pricing	continuous, on exchanges	infrequent appraisals (smoothed)
Return drivers	supply and demand, global growth, inventories	crop or lumber prices, yields or growth, land values
Volatility	high	low as reported (partly smoothing)
Key risks	demand shocks, geopolitics, weather, leverage in futures strategies	weather, disease, global trade and competition, illiquidity, fixed costs
Supply response	slow (production lead times)	slow (growing cycles)

Commodities

Supply comes from production and inventories, and demand from end users, with investors a secondary force on both sides. Gold is a special case: investors and central banks hold it as a store of value, so it often acts as a safe haven. The key feature is the slow supply response : producers cannot change output quickly. Farmers need at least a growing season, and new mines or oil infrastructure can take years. Supply is therefore too low in booms and too high in slowdowns, and prices take the strain. Weather, which producers cannot control, adds more swings.

These commodity return drivers help explain the history: over long samples, commodities have beaten global stocks and bonds on average but with much higher volatility. They had their worst year in the 2007–2009 crisis, then their best year as economies recovered. Commodity strategies also often use leverage, and commodity prices react strongly to geopolitical risk and the weather.

Farmland and timberland

Their returns come from multiple growing seasons (farmland) or the long forest growth cycle and the demand for lumber (timberland). Reported figures look attractive, with low volatility, but several risks are real:

• Liquidity is very low.
• Fixed costs are high (land care, seed, fertilizer), so cash flow can go negative.
• Revenue varies with weather risk : drought and flooding can wipe out a harvest. Weather is a unique and largely outside risk for these assets, unlike commercial buildings.
• Global trade risk : they produce commodities that are traded and consumed worldwide, so trade interruptions and growing competition can cut prices. Past returns may be hard to repeat.

Vacant or raw land that has not been prepared for use carries more risk than farmland or timberland.

Exam tip Low reported volatility on land is partly a product of appraisals. Do not read it as low risk.

Are commodities an inflation hedge?

Memorize

An inflation hedge is an asset whose returns rise with inflation, so it protects purchasing power. The argument for commodities is direct: energy and food are components of consumer prices, so commodity price changes are partly the inflation being measured.

Commodity prices are far more volatile than reported inflation. Consumer inflation covers many items whose prices move slowly, such as housing, and uses statistical smoothing, while commodity prices move in real time. That is why commodities lead and exaggerate inflation moves.

The evidence is consistent with this:

• Higher or rising inflation: commodity returns are strong.
• Lower or falling inflation: commodity returns are weak and often negative.
• Stable inflation: commodity returns have tended to be low but positive.
• Farmland and timberland: little evidence of a pattern. They do not suffer in low-inflation periods and also do not track rising inflation, so their correlation with inflation is near zero.

A hedge needs a high correlation with the exposure being hedged. Commodities have by far the highest correlation with inflation; farmland and timberland have near-zero or slightly negative correlation, which is why they are the weaker hedges even though their returns hold up in every regime.

How much do they diversify?

Diversification potential is measured by correlation with stocks and bonds , not by return or volatility. Lower correlation, closer to zero, means more diversification.

Portfolio roleall three diversify; only commodities track inflation

• Inflation Memorize commodities rise with inflation, fall when it eases
  • Commodities Memorize best inflation hedge; strong when rising, weak when falling
  • Farmland and timberland Memorize little link to inflation; returns hold up in all regimes
• Correlation with global stocks Memorize from lowest to highest
  • Timberland about zero
  • Farmland low
  • Commodities moderate, around 0.4; all tied to the business cycle
• Correlation with global bonds Memorize about zero for all three

• Bonds: about zero correlation for all three.
• Stocks: timberland the lowest (about zero), farmland low (about 0.1), commodities moderate (about 0.4). All three are tied to the business cycle, so some positive correlation is expected.
• Among themselves: farmland and timberland are fairly correlated with each other (about 0.4) and slightly negatively correlated with commodities.

Commodity indexes differ in how heavily they weight energy, so the commodity index chosen changes exposure to specific sectors, but the low correlation with traditional assets holds across indexes.

$$\sigma_p = \sqrt{w_1^2\sigma_1^2 + w_2^2\sigma_2^2 + 2\,w_1 w_2\,\rho\,\sigma_1\sigma_2}$$

This is the standard two-asset formula from portfolio mathematics. Here is how correlation drives the diversification benefit.

Two cautions. First, appraisal smoothing flatters farmland and timberland: their reported standard deviations and correlations are lower than their true economic values, so the calculation above would overstate the benefit if reported figures were used without adjustment. Second, correlations with stocks are positive for all three because they share the global business cycle.

Go deeper Why commodity indexes differ

Some commodity indexes are heavy in energy, while others are more balanced across energy, metals and agriculture. Index returns therefore depend on which sectors dominate, and so does their behavior in inflation shocks (an oil-led surge versus a food-led one). The conclusions on inflation and diversification refer to broad commodity indexes.

Go deeper Raw land as the riskiest land type

Raw land earns no operating income, so its return rests on price change alone and on finding a better use for the land. Its value depends on future development, zoning and the best alternative use. That is why it carries more risk than farmland or timberland, which at least produce crops or timber while the investor waits.