Track 04 · Risk & Portfolio Building
Volatility, beta and drawdowns
Volatility is not the same as risk, but it decides whether you can hold a plan long enough for it to work.
Volatility is swing; risk is permanent loss. The depth of the fall is what decides whether your plan survives it.
Illustrative. The maths of recovery: a 50% loss needs a 100% gain to get back to even.
Volatility is movement
Volatility measures how widely a price swings. By itself it is discomfort rather than permanent loss: a share that doubles and halves has been volatile while leaving you where you started.
Real, permanent risk comes from leverage, from needing the money at the wrong time, and from businesses that fail. Volatility becomes dangerous mainly when it forces you out of a position.
Beta in plain terms
Beta compares a stock’s movement to the market: 1.0 moves with it, 1.5 swings about half again as hard, 0.7 less. It is measured from history, so it is a description rather than a promise.
Low-beta stocks have historically fallen less in downturns and are useful for defensive allocations, while high-beta names amplify both directions.
- Beta above 1: amplifies market moves, up and down.
- Beta below 1: steadier, often slower-growing businesses.
- Beta can change: a young company’s beta is noisy and short-lived.
Drawdown: the real test
A drawdown is the peak-to-trough decline of an investment. The number that matters is the largest you have personally lived through and still held, because your future plan is only as good as that behaviour.
Knowing a position could fall 40% before it recovers lets you size it so that outcome is survivable, which is the next lesson.
Three things to remember
- 01Volatility is swing; risk is permanent loss. Volatility can still force bad decisions.
- 02Beta describes relative movement from history rather than a guarantee.
- 03Size positions so the plausible drawdown is one you can hold through.
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