An asset class is a group of investments that behave similarly. Knowing the handful that matter is enough to build almost any portfolio.
The core classes
| Class | What it is | Role in a portfolio | Typical risk |
|---|---|---|---|
| Stocks (equities) | Ownership in companies | Long-term growth | High |
| Bonds (fixed income) | Loans to governments/companies | Income, stability | Low–medium |
| Cash & equivalents | Savings, money market, T-bills | Safety, liquidity | Very low |
| Real assets | Real estate, commodities | Inflation hedge | Varies |
| Crypto | Digital assets | Speculative growth | Very high |
Stocks
When you own a stock, you own a slice of a real business and share in its growth (and its losses). Over long periods, equities have produced the highest returns of the core classes — with the largest swings along the way.
Bonds
A bond pays interest and returns its face value at maturity. Bonds usually move more calmly than stocks and can rise when stocks fall, which is why they are used to steady a portfolio.
Funds wrap them up
You rarely buy these one at a time. ETFs and mutual funds bundle many holdings into a single purchase — see Understanding ETFs & Stocks.
Different classes do not move together. Holding several smooths the ride without giving up much long-term return — the closest thing investing has to a free lunch.
How they fit together
The mix you choose between these classes is your asset allocation — the single biggest driver of your results over time. That is the next page: Asset Allocation.