Asset Classes: Stocks, Bonds, and Cash

Before building a portfolio you need to know what you actually hold. "The market" is not one thing but a few asset classes that behave in reliably different ways. Confusing them is how people expose next year's rent to steep swings, or leave decades-away savings eroding in a bank account. This lesson is educational, not personalised advice: it describes general behaviour, names no product, and treats every figure as illustration, not a promise. Knowing how each class behaves is what lets you match what you own to when you will need it.

Stocks: owning a piece of a business

A share is fractional ownership of a company. When it prospers, owners gain through rising prices and sometimes dividends; when it struggles, owners absorb the losses. That ownership is why stocks have historically carried the highest expected long-run return of the three classes — and the largest swings. A stock can fall by a third in a year, and nothing forbids it. Ownership means sharing the full range of a business's fortunes, good and bad.

Bonds: lending at interest

A bond is a loan to a government or company, repaid with interest and the return of principal on a set date. As a lender rather than an owner you face a narrower range of outcomes: steadier income, lower expected return. The main hazard is interest-rate risk — when prevailing rates rise, existing bonds paying less become worth less, so their market price falls. Bonds are generally calmer than stocks, not risk-free.

Cash and cash equivalents: safe but eroding

Cash — savings accounts, money-market instruments, short deposits — offers stability and instant access. The balance never swings. Its quiet danger is inflation: if prices rise faster than the interest earned, the money buys less each year even as the number holds. Cash preserves a nominal amount and slowly loses purchasing power.

The spectrum and the clock

The three form a spectrum: cash (low risk, low return), bonds (moderate), stocks (higher expected return, higher volatility). Your mix should follow time horizon — how long until you need the money. A long horizon can ride out volatility; a short one cannot. The same holding can be prudent for a thirty-year goal and reckless for a two-year one.

Illustratively, imagine that over a long period stocks average about 7% a year after inflation, bonds about 3%, and cash near 0%. A £10,000 stake compounding for thirty years would then reach roughly £76,000, £24,000, and £10,000. The gap is the reward for tolerating the stock's swings along the way. These figures are illustration only, not a forecast — real returns vary, and some decades disappoint.

Now shorten the clock. You are buying a home in eighteen months but hold the deposit in stocks because they "return more." A routine 30% drawdown arrives two months before completion, with no time to recover, so you sell at the bottom and lock in the loss. Here the higher expected return was irrelevant; the horizon was too short to survive the volatility. For that money, cash was the correct choice, not the timid one.

Long-run studies of markets spanning more than a century and dozens of countries — such as those compiled in the Global Investment Returns Yearbook by Dimson, Marsh and Staunton — have found a consistent pattern: over long horizons, equities tended to outperform bonds, and bonds outperformed cash, in nearly every market examined. This is a historical tendency, not a law. The outperformance came with far larger swings, including multi-year declines, and was never guaranteed in any single period. Past performance does not predict future returns; the pattern describes what happened, not what must happen next.

• "Stocks are just gambling." — Gambling has a negative expected value; owning productive businesses has historically had a positive one. The volatility is real, but the two are not the same.
• "Bonds are completely safe." — They are steadier than stocks, but rising interest rates can lower their price and inflation can erode their fixed payments.
• "Cash carries no risk." — It carries inflation risk. A balance that never falls can still lose much of its purchasing power over a couple of decades.
• "More risk always means more return." — Risk widens the range of outcomes; it does not guarantee a better one.

You will be given several goals with different time horizons and asked to place each on the risk-return spectrum, then justify which asset class fits and why.

Think Like a Maester: Do not ask which asset class is best. Ask which one matches the clock — the right answer changes entirely with when you will need the money.

1. What is the fundamental difference between owning a stock and owning a bond?
2. Why is cash, despite never falling in nominal value, still exposed to a serious risk?
3. What is interest-rate risk, and which asset class does it most affect?
4. Why should time horizon influence how much volatility you accept?
5. Why is the long-run historical outperformance of stocks a tendency rather than a guarantee?

Stocks, bonds, and cash occupy different points on the risk-return spectrum: ownership with high expected return and high volatility, lending with steadier and lower returns, and cash that is stable in name but eroded by inflation. History shows a long-run tendency for stocks to outperform, always with larger swings and never promised in any single stretch. The craft is not picking the "best" asset but matching each class to the time horizon of the money you are investing.

• Risk and Return
• Funds and Diversification