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BCG Growth-Share Matrix BCG 成長-市佔矩陣
Released已發布 methodology methodology
Apply BCG Growth-Share Matrix to analyze a product or business unit portfolio for resource allocation decisions. Use this skill when the user needs to prioritize investments across multiple products, decide which products to grow vs harvest vs divest, or evaluate a portfolio's balance — even if they say 'which products should we invest in' or 'portfolio strategy' without naming BCG.
商業方法論技能：BCG Growth-Share Matrix 分析與應用。
Overview概述
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使用時機
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
Methodology 方法論
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輸出格式
# BCG Matrix Analysis: {Company/Portfolio}
Examples範例
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注意事項
- 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參考資料
- 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
Tags標籤
business-strategybcg-matrixportfolio-management