Industry Size, Growth, Profitability, and Market Share Trends

Estimating Industry Size

The top-down approach starts with an aggregate figure, often published by a government statistical agency or a third-party research firm, that measures total revenue across the entire industry. This works well when the industry contains many small or private participants whose individual figures are unavailable, but the data can lack the granularity needed to isolate closely related sub-segments.

Bottom-up approach sums the revenue reported by individual industry participants. This is more precise when the industry is dominated by large, transparent, publicly listed firms with clear segment reporting. It becomes unreliable when a large share of participants are private (and therefore undisclosed) or when major players operate across multiple industries, since including their total revenue overstates the size of the specific industry being measured.

Industry Growth Characteristics

Because the sum of all industry growth rates equals overall economic growth, a mature industry, one that has largely saturated its addressable market, grows near or below the broader economy’s growth rate. Analysts monitoring mature industries focus on disruptive threats and the pace of eventual decline.

Growth industries, by contrast, expand faster than the economy and remain largely insensitive to the business cycle because they have not yet reached full market penetration. The key uncertainty here is how long above-trend growth can be sustained and where the eventual saturation point lies.

Structural shocks, regulatory shifts, technological disruption, or macroeconomic shocks cause sharp, permanent changes in an industry’s growth trajectory, separate from its underlying business-cycle sensitivity.

Industry Profitability Measures

Profitability is most reliably measured using:

• \(\text{Operating margin} = \text{Operating income} \div \text{Total revenue} \)
• \(\text{Return on invested capital (ROIC)} = \text{NOPAT} \div \text{Average invested capital} \)

Comparing ROIC to the industry’s weighted average cost of capital (WACC) indicates whether the industry as a whole creates economic value. A positive ROIC–WACC spread indicates the industry earns returns in excess of its capital costs; a negative spread indicates the reverse. When private-company data is scarce, analysts either assume private firms share the profitability profile of comparable public peers or rely on government or third-party survey data.

Market Share Trends and Industry Concentration

Market share is calculated by dividing a participant’s revenue by total industry revenue, and, given the challenges of estimating industry size, this figure is best treated as a range rather than a precise point estimate.

The Herfindahl–Hirschman Index (HHI) measures concentration:

$$HHI=\sum_{i=1}^{n} s_i^2$$

where each market share \(s_i\) is expressed as a whole number (e.g., 25% share = 25, not 0.25). A higher HHI signals greater concentration, which corresponds to lower competitive intensity and, all else equal, higher industry profitability. A monopoly produces the maximum possible HHI of \(10,000 (100^2)\).

Example

Consider the fictional Continental Bottling industry, comprising four competitors with market shares of 40%, 30%, 20%, and 10%.

$$ \begin{align*}
HHI & =\sum_{i=1}^{n} s_i^2 \\
&=40^2+30^2+20^2+10^2 \\
& =1,600+900+400+100=3,000
\end{align*} $$

Suppose the two smallest competitors (20% and 10%) merge, creating a combined entity with a 30% share, alongside the existing 40% and 30% firms:

$$ \begin{align*}
HHI_\text{(new)} &=40^2+30^2+30^2 \\
&=1,600+900+900=3,400 \end{align*} $$

The 400-point increase in HHI following the merger illustrates why regulators scrutinize consolidation in already-concentrated industries — the combination measurably reduces the number of independent competitors and raises the concentration score.

Question

An industry consists of five firms with market shares of 35%, 25%, 20%, 12%, and 8%. The Herfindahl–Hirschman Index for this industry is closest to:

1. 100
2. 2,458
3. 10,000

Solution

The correct answer is B.

$$ \begin{align*}
HHI & =\sum_{i=1}^{n} s_i^2 \\
& =35^2+25^2+20^2+12^2+8^2 \\
& =1,225+625+400+144+64=2,458 \end{align*} $$

This is the sum of the squares of each firm’s market share stated as a whole number, which is the correct application of the HHI methodology.

A is incorrect. A value of 100 corresponds to the sum of the market shares themselves.

$$HHI=35+25+20+12+8=100$$

Rather than the sum of their squares. This confuses the HHI calculation with a simple summation of shares.

C is incorrect. A value of 10,000 represents the maximum possible HHI, which occurs only in a pure monopoly with a single firm holding 100% market share \((100^2 = 10,000)\). This industry has five competitors, so its concentration score falls well short of this ceiling.