The falling out between Donald Trump and Elon Musk is one of the more prominent news stories of 2025. We will probably never know the whole story. But at least one part of the argument was over the matter of the US national debt and what to do about it.

There’s something interesting in the world of finance called the FIRE movement. It stands for Financial Independence Retire Early. It has a big following online and a set of rules for achieving its headline goal, including one rule that’s described as extreme saving. The objective is to save enough money so that the passive income (interest, dividends etc) that derives from it is enough to cover one’s expenses. At that point, it’s retirement time. But the time horizon is not 30+ years. The objective of the FIRE bugs is to get there fast.

For decades, the CRB Index has tracked the price of a selection of “core” commodities. These are: Aluminium, Cocoa, Coffee, Copper, Corn, Cotton, Crude Oil, Gold, Heating Oil, Lean Hogs, Live Cattle, Natural Gas, Nickel, Orange Juice, RBOB Gasoline, Silver, Soybeans, Sugar, and Wheat. Like all price indexes, the index reflects the ups and downs in the price of this basket of commodities. Also like all price indexes, the weightings are important. The commodities in the CRB index are arranged in 4 groups, with different weightings: Energy: 39%, Agriculture: 41%, Precious Metals: 7%, Base/Industrial Metals: 13%. As such, the ups and downs in the index are most sensitive to changes in energy and agriculture prices predominantly.