BCG Growth-Share Matrix

Overview

The BCG Matrix classifies products or business units into four quadrants based on market growth rate (Y-axis) and relative market share (X-axis). It guides resource allocation: where to invest, where to harvest cash, and what to divest.

When to Use

Trigger conditions:

• User managing multiple products or business units and needs to prioritize
• User asks "which products should we invest in vs cut?"
• User needs a portfolio-level view of their business
• User mentions "cash cow", "star product", or "portfolio strategy"

When NOT to use:

• For single-product strategy → use SWOT or Blue Ocean
• For industry-level analysis → use Porter's Five Forces
• When detailed financial modeling is needed → use DCF or financial ratios

Framework

IRON LAW: Relative Market Share, Not Absolute

The X-axis is RELATIVE market share = your share / largest competitor's share.
A company with 20% share in a market where the leader has 40% = 0.5x (Low).
A company with 20% share where the next largest has 10% = 2.0x (High).

NEVER use absolute market share. A 30% share means nothing without knowing
the leader's share.

IRON LAW: Plot THEN Strategize

Place ALL products/units on the matrix BEFORE deciding strategy.
Portfolio balance matters — a company with only Stars has a cash crisis
(Stars consume cash). A company with only Cash Cows has no growth pipeline.

Step 1: Define the Portfolio Units

List all products, product lines, or business units to analyze. Each must be:

• A distinct unit with its own market and competitors
• Measurable in terms of revenue, market share, and market growth

Step 2: Gather Data for Each Unit

For each unit, determine:

• Market growth rate: Annual growth rate of the total market (not your revenue growth). Typically, >10% = High growth.
• Relative market share: Your market share ÷ largest competitor's market share. >1.0x = High.

Step 3: Plot on the Matrix

	High Relative Market Share	Low Relative Market Share
High Market Growth	⭐ Stars — High share in growing market. Generate revenue but consume cash to maintain position.	❓ Question Marks — Low share in growing market. Need heavy investment to gain share, or divest.
Low Market Growth	🐄 Cash Cows — High share in mature market. Generate surplus cash with low investment needed.	🐕 Dogs — Low share in slow market. Minimal cash generation, limited potential.

Step 4: Determine Strategy per Quadrant

Quadrant	Default Strategy	Nuance
Stars	Invest to maintain/grow share	Will become Cash Cows as market matures
Cash Cows	Harvest — maximize cash extraction with minimal investment	Fund Stars and selected Question Marks
Question Marks	Selective invest OR divest — pick winners, cut losers	Most critical decision — not all can become Stars
Dogs	Divest or reposition	May keep if synergies with other units exist

Step 5: Assess Portfolio Balance

Check the overall portfolio health:

• Healthy: Mix of Cash Cows (funding) + Stars (growth) + 1-2 Question Marks (pipeline)
• Unhealthy: All Cash Cows (no growth), all Stars (cash drain), all Dogs (declining)

Output Format

# BCG Matrix Analysis: {Company/Portfolio}

## Portfolio Units

| Unit | Revenue | Market Growth | Rel. Market Share | Quadrant |
|------|---------|--------------|-------------------|----------|
| {Product A} | {$X} | {X%} | {X.Xx} | Star/Cash Cow/QM/Dog |

## BCG Matrix Placement

| | High Share (>1.0x) | Low Share (<1.0x) |
|---|---|---|
| **High Growth (>10%)** | ⭐ {list Stars} | ❓ {list Question Marks} |
| **Low Growth (<10%)** | 🐄 {list Cash Cows} | 🐕 {list Dogs} |

## Strategic Recommendations

### Stars — Invest
- {Product}: {specific investment recommendation}

### Cash Cows — Harvest
- {Product}: {how to maximize cash extraction}

### Question Marks — Decide
- {Product}: Invest / Divest — {rationale}

### Dogs — Divest/Reposition
- {Product}: {recommendation}

## Portfolio Health Assessment
{Overall balance evaluation and rebalancing recommendations}

Examples

Correct Application

Scenario: BCG for a Taiwanese electronics company with 4 product lines

Unit	Market Growth	Rel. Share	Quadrant	Reasoning
Laptop line	3%	1.8x (leader)	Cash Cow ✓	Mature market, dominant position
Gaming peripherals	18%	0.4x	Question Mark ✓	Fast-growing but small player
Server components	12%	1.2x	Star ✓	Growing market, leading position
Feature phones	-2%	0.3x	Dog ✓	Declining market, minimal share

Strategy: Harvest Laptop cash → fund Server (maintain Star) + selective invest in Gaming (Question Mark with potential). Divest Feature phones.

Incorrect Application

Scenario: Same company

What went wrong:

• Used absolute market share (25%) instead of relative (25% / leader's 30% = 0.83x) → Would misclassify as High Share when it's actually Low. Violates Iron Law.
• Decided "invest in everything" without plotting first → No portfolio trade-off analysis. Violates Iron Law: plot then strategize.

Gotchas

• Market growth ≠ your revenue growth: A product growing 20% in a market growing 25% is losing share. Use market growth rate, not company revenue growth.
• Relative share threshold: The 1.0x cutoff is a guideline. In fragmented markets with no clear leader, adjust the threshold. Document your reasoning.
• BCG is a snapshot: Markets evolve. Stars become Cash Cows, Question Marks become Dogs. Reassess annually.
• BCG ignores synergies: A "Dog" that provides key components to a "Star" may be worth keeping. Factor in cross-unit dependencies.
• Not all Question Marks can be funded: The hardest decision. Use additional criteria (market fit, team capability, strategic importance) to choose which to invest in.

References

• For GE-McKinsey Matrix as an alternative (multi-factor version), see references/ge-mckinsey.md
• For comparison with other strategy frameworks, see references/framework-comparison.md