Risk and volatility

In investing, "risk" usually means something more specific than "the chance of losing everything". It mostly means uncertainty: how widely an investment's value might swing around before you need the money. The usual name for those swings is volatility.

This week was a good live example. On Wednesday Microsoft jumped 6.7% in a single day and Nvidia fell 3.2%. Brent crude, the oil price, dropped 8.7%. Meanwhile a broad global fund like Vanguard's ESG Global All Cap moved about 1.4%. Same day, same news, very different sizes of move.

Why the difference? A single company's price reacts to everything about that one business: its results, one big customer, one political decision. A fund holding thousands of companies averages those surprises out, so its daily moves are usually smaller. Single shares, themed funds and commodities are generally more volatile than broad funds.

Two useful ideas follow. First, a drawdown (how far something falls from its peak) is the number that tests your nerve. A share that is volatile can easily fall 30% or more from its high at some point, as ITM Power and Enphase have over the past year. Second, volatility is not the same as permanent loss. A fund that drops 10% and then recovers has cost you nothing unless you sold at the bottom.

That is why investors talk about risk tolerance: how much up-and-down you can sit through without panicking. Your time horizon matters a lot here. Money you need in a year should not be riding on volatile shares; money for twenty years from now can usually ride out several bad patches.

The VIX, often called the "fear gauge", measures how much volatility traders expect in US shares over the next month. It fell 20% on Wednesday to 16.6 as the election uncertainty cleared, a sign that the market's nerves had calmed. A VIX around 12-20 is ordinary; above 30 usually means real fear.

The practical lesson: expect swings, size them to your time horizon, and judge an investment over years rather than days.