Can You Be Too Diversified?

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Diversification is one of the most widely recommended rules in investing; the concept is simple: Don’t put all your eggs in one basket.

A family can manage a portfolio across multiple wealth managers, Portfolio Management Services (PMSes), Alternative Investment Funds (AIFs), and individual equities is common when allocating capital. Spreading wealth across different assets aims to manage risk. However, holding too many investments leads to over-diversification. After a specific point, adding positions fails to lower volatility while adding expenses like fees, duplicate holdings, tax complications, etc.

1. Diminishing Marginal Risk Reduction

A portfolio consists of two kinds of risks: Systematic Risk (Broad market) and unsystematic risk (Company-specific).

Company-specific risk involves operational, management, or regulatory issues unique to an individual firm. By diversifying the portfolio and spreading capital across different stocks, a lower return in one company/sector can be balanced by better performance in another. In contrast, Systematic or broad market risk reflects general macroeconomic factors like interest rate changes and inflation, which impact multiple stocks and may not be eliminated by diversifying the portfolio and by adding more holdings.

Research has shown that holding 20 to 30 well-chosen securities removes 80% to 90% of company-specific risk. Whereas expanding the portfolio beyond 20 to 30 individual holdings yields minimal further risk reduction. Beyond this range, remaining volatility comes from overall market movements, which means that adding extra positions may not provide additional downside protection.

2. Return Dilution Rate

While risk reduction flattens out, adding excess holdings dilutes overall gains. When capital is split into many small micro-allocations, strong performance from a single investment makes little difference to total net worth. And this process is known as “Diworsification“.

To understand how return dilution impacts wealth accumulation, consider two investors who start with the same capital of ₹5 Crores. Both investors happen to select the same stock that grows by 500%. However, because of how they structured their portfolios, their final returns tell two completely different stories.

When position sizes become too small, even an exceptional stock choice loses its ability to meaningfully impact overall net worth.

3. Holding Overlap & Portfolio Duplication (“Phantom Diversification”)

Holding multiple active funds, PMS strategies, or sector products often results in Phantom Diversification. This situation occurs when different managers buy the exact same underlying companies. Since many managers select holdings from the same universe, owning multiple funds of the same category might create repeated exposure to a few dominant companies.

Using analysis tools shows that combining broad equity funds with specialized strategies may sometimes still result in overlapping exposure to the same companies. Investors end up paying management fees across multiple accounts while carrying a stock concentration like a single broad index fund.

4. Total Cost Burden (Fee Friction)

Having multiple active strategies, PMS setups, and specialized funds increases the ongoing costs for investors. Broad market index funds charge expense ratios of around 0.03% to 0.10% p.a. whilst specialized active strategies and thematic solutions often charge management fees ranging from 1% p.a. to 2.50% p.a. or more, alongside potential profit-sharing terms.

5. Administrative Drag & Additional Charges

Managing dozens of positions across multiple funds, demat accounts, and wealth managers exposes capital to hidden operational charges and administrative friction:

• Layered Account & Platform Fees: Maintaining multiple active accounts, Portfolio Management Services (PMS) mandates, and specialized funds incurs recurring custodian fees, account maintenance charges, and platform costs across different entities.
• Cumulative Transaction Charges: Frequent buying and selling across multiple managers accumulate statutory expenses like Securities Transaction Tax (STT), stamp duty, brokerage fees, and GST on management charges that directly reduce net capital growth.
• Administrative Overhead: Consolidating statements, tracking dividend receipts, reviewing performance reports, and organizing documentation across dozens of holdings increases administrative complexity without adding financial value

6. Portfolio Efficiency & Structural Optimization

Instead of using complex mathematical formulas, portfolio efficiency can be evaluated by comparing actual net returns against total ongoing costs. Holding dozens of overlapping funds or stocks often leads to market-average returns reduced by management fees, transaction expenses, and tax liabilities.

A structured approach to maintaining portfolio efficiency is the Core-and-Satellite model:

• The Core (60%–70% of Capital): Capital allocated to lower-cost, index and actively managed diversified funds to participate in general economic growth while keeping fee friction low.
• The Satellite (30%–40% of Capital): Limited to a small number of specific stocks or targeted strategies, where each position weighs 5% to 10% of total capital, which is large enough to influence total portfolio returns.

Restructuring an Over-Diversified Portfolio

Over a period, it is not uncommon to see an inadvertently created over-diversified portfolio. However, pruning it back into shape requires a careful, systematic approach. It can be done by making sure to get rid of similar investments after comparing investment objectives and transaction costs, while ensuring you don’t lose or sell well-performing assets, stocks, or funds in the process. Be mindful of taxes in the process.

An objective process brings analytical clarity to compare expense ratios, identify duplicate stock exposures across accounts, and evaluate transaction costs without emotional bias. It is also crucial to ensure that core, high-performing assets are preserved while redundant or sub-scale holdings are eliminated.

As Harry Markowitz famously remarked, “Diversification is the only free lunch in investing”

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