Diversification — How Much Is Enough?
What diversification really protects you from — and where it stops helping
What Diversification Does
Diversification reduces idiosyncratic risk — the risk that any single company-specific event destroys a meaningful portion of your portfolio. It does not reduce market risk, currency risk, or systemic risk; those affect all stocks together and require different tools.
The academic finding is that most of the diversification benefit is captured by the first 15–20 well-chosen stocks. Beyond that, additional names reduce idiosyncratic risk only marginally while making the portfolio increasingly difficult to monitor.
The Concentration Argument
Investors with deep knowledge of a small number of businesses sometimes hold concentrated portfolios — five to ten positions — accepting higher volatility in exchange for the ability to invest only in their highest-conviction ideas.
This approach requires real expertise, real time, and real psychological tolerance for individual position swings. It is not for most investors. But for those who can do the work, focused portfolios have historically produced strong long-term outcomes.
Diversification Within an EGX Portfolio
Within a focused Egyptian equity portfolio, diversification across sectors matters as much as diversification across names. Holding five Egyptian banks is much less diversified than holding one bank, one consumer staple, one industrial, one real estate, and one telecom.
Sector diversification on the EGX is constrained by the market's natural bias toward financials, real estate, and consumer goods. A sensibly diversified portfolio reflects this — there is little point in forcing exposure to sectors that are barely represented locally.
Over-Diversification
Owning 50 or 100 individual stocks rarely improves expected returns and almost always degrades the quality of monitoring. At that level, an investor would be better served by an index fund — which provides full market exposure at much lower cost and with no monitoring burden.
The right question is not 'how many names' but 'how much true conviction'. A focused portfolio of researched names can outperform a sprawling portfolio of half-understood ones over long periods.
FAQ
How many stocks should I hold?
For most active investors, 10–25 well-chosen names provide the bulk of diversification benefit while remaining monitorable. Below 10 requires unusual expertise and conviction. Above 30 typically dilutes results without proportionally reducing risk.
Should I diversify across countries as well as sectors?
International diversification reduces single-country risk — including currency and political risk — and is sensible for any portfolio with a long horizon. The right balance depends on your overall financial situation and where your other assets and income are located.
Is an index fund 'too much' diversification?
Not necessarily. An index fund provides instant, low-cost diversification and is the right answer for many investors. It is only 'too much' for investors who have the time, knowledge, and discipline to research and hold a focused portfolio of higher-conviction individual names.