Diversification
Diversification is the practice of spreading investments across different assets, sectors, or geographies to reduce risk. A diversified portfolio is less volatile than any single holding because losses in one area are offset by gains in others.
The core principle: don't put all your eggs in one basket. Owning 500 stocks (via an index fund) means one company going bankrupt barely affects your portfolio. Owning only that one company means a single bad earnings report can devastate your savings.
True diversification spans asset classes (stocks, bonds, real estate), geographies (US, international, emerging markets), and sectors (technology, healthcare, energy, etc.).
Modern Portfolio Theory (Markowitz, 1952) showed mathematically that a diversified portfolio delivers a higher return per unit of risk than any individual asset — what he called the "only free lunch in investing."
Related terms
- Asset Allocation
- Asset allocation is the percentage split of a portfolio among different asset classes — typically stocks, bonds, and cash. It is the primary driver of long-term portfolio risk and return.
- Index Fund
- An index fund is a portfolio of stocks or bonds designed to replicate the performance of a market index, such as the S&P 500. Index funds have lower fees than actively managed funds because no stock-picking is required.
- Portfolio Rebalancing
- Rebalancing is the process of realigning the weights of portfolio holdings back to a target asset allocation — selling assets that have grown above target and buying those that have fallen below.