What counts as different
Two assets are only diversifying if they tend to move for different reasons. A portfolio split evenly between ten bank shares is not diversified in any meaningful sense: all ten respond to the same interest rate and credit cycles. Genuine diversification comes from combining assets with different return drivers: listed equities, private credit, property and cash each respond to different parts of the economic cycle, and often at different times.
Correlation is not fixed. Assets that behave independently in calm markets can move together in a shock, when investors sell whatever can be sold rather than what they planned to sell. This is why a sound portfolio is built for a range of conditions, not just the one the market happens to be in today.
The cost, and the limit
Diversification also has a cost. Spreading capital across more assets can smooth returns, but it can also dilute the effect of a strong individual holding. The right level of diversification depends on an investor's time horizon, liquidity needs and tolerance for variation in outcomes, which is why it is assessed per investor rather than applied as a single rule.
None of this is a guarantee against loss. Diversification manages risk; it does not remove it, and no combination of assets can promise a particular return. What it does is reduce the chance that a single event determines the outcome of an entire portfolio.
The useful question
For investors building or reviewing a portfolio, the useful question is not "how many assets do I hold" but "how many genuinely different things am I exposed to, and have I checked that assumption recently." Markets change, and a mix that was well diversified two years ago may not be today.
This article is general information only. It does not take into account any person's objectives, financial situation or needs, and is not personal financial product advice.
