Diversification

Diversification combines exposures to reduce dependence on particular sources of loss. In portfolio theory, risk depends on asset weights, individual variability, and covariance. Assets need not be uncorrelated for diversification to help, and combining holdings does not guarantee superior returns or protection from all losses.

Diversification changes the combination of exposures so one source of loss has less influence on the whole. For financial portfolios, both individual volatility and the way returns move together matter. Perfect independence is unnecessary: imperfect positive correlation can still provide a diversification benefit. Counting holdings without examining their shared drivers can hide concentration.

The practical question is which shock would affect several components at once. Customers from different industries may still depend on the same funding source; backups may still rely on the same electricity supply. Diversification can reduce particular risks, but it brings costs and does not guarantee gains or protection against every common shock. The desired mix depends on the objective and constraints.

When to use it

When a single exposure or common driver could produce an unacceptable loss, or when a collection appears varied but may share important dependencies.

How it can help

Identify shared drivers and examine the whole combination rather than counting assets, customers, or sources. Compare potential risk reduction with costs, complexity, and the requirements of the objective.