Sector concentration risk in dividend portfolios
Why dividend portfolios drift into a few sectors, how holding, sector and income weights differ, and how to read the effective number of holdings (1/HHI).
- Yield-focused screens often lean toward a handful of sectors, so concentration creeps in.
- Holding weights, sector weights and income weights can tell three different stories.
- Higher-yielding holdings make up a bigger share of income than of value.
- Effective number of holdings = 1 ÷ the sum of squared weights.
Why do dividend portfolios drift into a few sectors?
- Screens favour certain business models. Mature, cash-generating industries such as utilities, telecommunications, financials, energy infrastructure and real estate tend to pay out more of their cash, so they dominate high-yield lists.
- Similar holdings look different. Five companies with different names may all depend on the same thing, such as interest rates, commodity prices or one regulator.
- Home bias. Investors often favour companies from their own country, and a home market may have fewer dividend payers in some sectors than others.
- Price drift. Holdings that rise grow into a larger share of the portfolio unless something changes.
- Yield chasing. Adding whatever currently yields most can pile more money into a sector that’s under pressure, since its prices have fallen and its yields have risen. See yield traps.
Holding, sector and income weights: a worked example
Imagine a hypothetical $100,000 portfolio split equally across five holdings. By value, it looks perfectly balanced. Now add each holding’s yield and sector.
| Holding | Sector | Value | Value weight | Yield | Annual income | Income weight |
|---|---|---|---|---|---|---|
| A | Energy infrastructure | $20,000 | 20% | 6% | $1,200 | 33.3% |
| B | Energy infrastructure | $20,000 | 20% | 5% | $1,000 | 27.8% |
| C | Utilities | $20,000 | 20% | 4% | $800 | 22.2% |
| D | Consumer staples | $20,000 | 20% | 2% | $400 | 11.1% |
| E | Technology | $20,000 | 20% | 1% | $200 | 5.6% |
| Total | n/a | $100,000 | 100% | 3.6% | $3,600 | 100% |
What the example shows
By value, energy infrastructure is 40% of the portfolio ($40,000 of $100,000). By income, it’s 61.1% ($2,200 of $3,600). Add utilities, which are often sensitive to similar forces such as interest rates, and 83.3% of the income ($3,000 of $3,600) comes from three holdings in two related sectors.
If holdings A and B each cut their dividends by half, income would fall by $1,100, from $3,600 to $2,500, a 30.6% drop, even though they’re only 40% of the portfolio’s value. Income concentration matters most to anyone relying on the cash.
Why can different sectors move together?
Sector labels don’t capture every shared risk. Holdings in different sectors can depend on the same outside forces, so a single change can hit several of them at once.
- Interest rates: businesses that carry a lot of debt or are valued mainly for steady income, such as some utilities, real estate and telecommunications companies, can share a sensitivity to borrowing costs.
- Commodity prices: energy producers, some pipelines and materials companies can all feel a swing in the same commodity.
- The credit cycle: banks, insurers and lenders can be affected together when borrowers struggle.
- One country or regulator: a rule change or a weak domestic economy can affect many holdings in the same market.
What is the effective number of holdings (1/HHI)?
The Herfindahl–Hirschman Index (HHI) is a simple concentration score: square each weight (as a decimal) and add them up. The effective number of holdings is 1 ÷ HHI. It answers: “This portfolio is as diversified as how many equal-sized holdings?”
- By value, each of the five holdings is 0.20. Squared: 0.04. Five of them: HHI = 0.20. Effective number = 1 ÷ 0.20 = 5.0. Equal weights give exactly the count of holdings.
- By income, the weights are 12/36, 10/36, 8/36, 4/36 and 2/36. Squared and added: (144 + 100 + 64 + 16 + 4) ÷ 1,296 = 328 ÷ 1,296 ≈ 0.253. Effective number = 1 ÷ 0.253 ≈ 3.95.
- By sector income, energy infrastructure is 22/36, utilities 8/36, staples 4/36 and technology 2/36. HHI = (484 + 64 + 16 + 4) ÷ 1,296 = 568 ÷ 1,296 ≈ 0.438. Effective number of sectors ≈ 2.28, even though four sectors are represented.
Concentration by value works the same way. A portfolio with one 50% holding and five 10% holdings has HHI = 0.25 + 5 × 0.01 = 0.30, so it behaves like about 3.3 equal holdings, not six.
Approaches investors use to manage concentration
There’s no single right method, and each comes with trade-offs. Some investors set a maximum weight for any one holding or sector, by value, by income, or both. Some direct new money or reinvested dividends toward underweight areas instead of selling. Some use broad funds alongside individual holdings to fill sector gaps. Each approach can lower income concentration, but it can also lower current yield or add costs, so the balance depends on your own goals.
How to check your own portfolio
The /portfolio checker does this arithmetic from numbers you enter. There’s no correct level of concentration; it’s a trade-off you can only judge against your own goals. See building a dividend income plan and dividend ETFs vs individual stocks.
- List each holding’s value, sector and annual dividend.
- Compute value weights and income weights separately.
- Group by sector and add up both kinds of weight.
- Compute 1 ÷ HHI for holdings and for sectors, by value and by income.
- Ask what a dividend cut in your largest income sector would do to your total income.
Frequently asked questions
How many dividend stocks make a diversified portfolio?
Why measure concentration by income instead of value?
Is sector concentration always bad?
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