Commodity investing contains a trap that catches almost every newcomer: the price on the news is not the return in your fund, and the gap can be enormous.

You are not buying oil

Nobody delivers barrels to your broker. Commodity funds buy futures contracts — agreements to buy at a set price on a set date. As each contract nears expiry, the fund sells it and buys the next one out. This is called rolling, and it happens continuously.

Contango: the silent leak

Usually, longer-dated contracts cost more than near-dated ones — a shape called contango, reflecting the cost of storing and financing the physical goods. So every roll sells low and buys high, by a little, forever.

The result: a commodity fund can lose money over years while the spot price is flat, purely from rolling. This is not a fee and it is not incompetence — it is the structure of the market. It is also why long-term buy-and-hold in a single-commodity fund is usually a poor idea.

The reverse shape, backwardation, means near contracts cost more than distant ones — typically when there is a shortage right now. Then rolling earns you a return. It happens; it is not the default.

No cash flow, again

Like gold, commodities pay nothing. A barrel of oil produces no dividend. Over the very long run, real commodity prices have tended to be roughly flat to declining, because humans keep getting better at extracting and substituting. The long-run case for commodities is diversification, not growth.

Where they genuinely help

  • Unexpected inflation. This is commodities' strongest suit — energy and food spikes hurt stocks and bonds at exactly the moment commodities rise. Few assets do that.
  • Supply shocks. Wars, embargoes and crop failures move commodities independently of the business cycle.

If you want exposure

Prefer a broad, diversified commodity index over a single commodity, and look at funds using optimised or laddered rolling rather than naive front-month rolling — the difference over years is substantial. And keep the position small; this is a satellite.

Summary

Commodity funds track futures, not the headline price. Contango quietly erodes returns, there is no income, and the real reason to hold them is protection against inflation surprises — not the expectation of long-run growth.