A successful stock investment can gradually become a financial risk when it accounts for too much of an investor’s portfolio. A share that doubles in value, employee stock awards or inherited investments can increase exposure to a single company without the investor making any additional purchases.
According to Hemant Sood, Founder and Managing Director of Findoc Group, the key consideration is not simply whether a company is performing well, but how much damage its failure could cause to an investor’s overall financial position.
How Concentrated Stock Holdings Can Affect Your Wealth
Consider an illustrative portfolio worth ₹1 crore, with 30% invested in a single stock. If that stock loses half its value, the investor would face a loss of ₹15 lakh, reducing the overall portfolio by 15%, assuming all other investments remain unchanged. Recovering from that decline would require a gain of approximately 17.6% on the remaining portfolio value.
Market history provides examples of how quickly individual stocks can fall. HDFC Bank shares declined 8.44% on January 17, 2024, following its quarterly results, while the Nifty 50 fell 2.09%, according to a report. One97 Communications, the listed parent of Paytm, lost around 42% over three trading sessions through February 5, 2024, after the Reserve Bank of India imposed restrictions on Paytm Payments Bank.
These cases involved different circumstances, but they illustrate how company-specific developments can affect individual holdings more sharply than the wider market.
Concentration can also limit an investor’s chances of benefiting from exceptional long-term performers. Research by Hendrik Bessembinder covering US stocks from 1926 to 2016 found that approximately 4% of companies generated the market’s entire net wealth creation above Treasury bills. Investors holding only a small number of stocks risk missing some of the companies responsible for these gains.
How Much Should You Invest in One Company?
Professional investment management follows diversification requirements. SEBI rules do not allow a diversified mutual fund to invest more than 10% of its net assets in the shares of a single company.
For individual investors, Sood suggests using 5% of the total financial investment portfolio as an initial reference point for exposure to one company. Holdings exceeding 10% warrant a formal review, while exposure above 20% calls for a planned assessment of whether the position should be reduced. The appropriate limits depend on financial goals, liquidity requirements and the investor’s ability to tolerate losses.
Investors can also calculate their limits based on the potential loss they are willing to accept. For example, if a 50% decline in a stock should reduce the overall portfolio by no more than 3%, the maximum allocation would be 6%. This is calculated by dividing the acceptable portfolio loss of 3% by the assumed stock decline of 50%.
The 50% fall is a stress-test assumption, not a limit on how far a stock can decline. Investments in financially fragile or illiquid businesses may require even smaller allocations.
Hidden Overlap Across Stocks and Mutual Funds
Assessing concentration requires more than checking the percentage invested in each direct stock holding. Investors should calculate exposure using the current market value of their financial investments, including direct shares, mutual funds, exchange-traded funds (ETFs) and managed portfolios. Their homes and operating businesses can be assessed separately when considering broader financial risks.
For example, an investor holding 8% of a portfolio directly in a company and another 20% through a fund that allocates 5% of its assets to the same company has an effective exposure of 9%, assuming the percentages are measured against the same total portfolio.
Investors should also examine exposure to common sectors and economic risks. Holding shares in five different banks, for instance, may still leave a portfolio vulnerable to the same credit cycle.
Employees who own substantial shares in their employer face another risk: their salary and investments could both suffer if the company encounters difficulties. Entrepreneurs should similarly consider whether their listed investments duplicate the risks already associated with their own businesses.
How to Monitor and Reduce Portfolio Concentration
Concentration can increase even when investors do not purchase additional shares. If a stock initially represents 10% of a portfolio and doubles in value while all other holdings remain unchanged, its portfolio weight rises to approximately 18.2%.
Sood recommends reviewing portfolio allocations every quarter, after significant market movements and whenever concerns about a company’s governance emerge. Investors can direct new savings towards other assets and gradually reduce oversized holdings to bring them closer to predetermined allocation limits.
Any decision to sell should account for applicable taxes and liquidity. Stop-loss orders can help investors manage risk, but they cannot guarantee an exit at the intended price, particularly when prices move sharply or trading is thin.
Ultimately, managing concentration is about ensuring that the performance of a single company does not have an outsized impact on long-term financial security. Regular reviews, clear allocation limits and an understanding of overlapping risks can help investors build a more balanced portfolio.
Disclaimer: This article is intended for educational and informational purposes only and does not constitute investment advice or a recommendation to buy or sell any security. Portfolio allocation decisions should reflect individual financial goals, risk tolerance, liquidity needs and tax considerations. Consult a SEBI-registered investment adviser before making investment decisions.