How to fill in the BCG Matrix
Sort a portfolio by market growth and market share, then decide where cash goes. This guide walks every block in the recommended order — what belongs there, the questions that unlock it, and patterns from real canvases.
The BCG matrix plots each product, business unit, or product line on two axes: how fast its market is growing, and how much share you hold relative to the largest competitor. Four quadrants follow — stars, cash cows, question marks, and dogs.
It is a cash allocation tool above all. The logic is that cash cows fund the question marks worth backing, some of which become stars, which mature into the next generation of cash cows. Read that way, the matrix answers a question annual planning usually dodges: which of our products is being subsidised by which, and is that deliberate?
Created by Bruce Henderson at the Boston Consulting Group in 1970. It remains the best-known portfolio management framework, and the most frequently criticised for reducing strategy to two variables.
Stars — High Growth, High Share
What is winning in a fast-growing market?
Market leaders in growing markets. They generate substantial revenue and consume just as much cash to defend position, so they are frequently cash-neutral despite looking like the best thing you own. The strategy is invest to hold: when growth eventually slows, a defended star becomes a cash cow, and an under-invested one becomes a dog.
Ask yourself
- Which products lead a market that is still growing?
- What would it cost to hold this position?
- Is anyone gaining on us here?
- What happens to this when growth slows?
Patterns that work
- Invest to hold share — under-investment here is expensive later
- Often cash-neutral: high revenue, high reinvestment
- Today's stars are the only source of tomorrow's cash cows
Question Marks — High Growth, Low Share
What could become a star, with money?
Products in attractive growing markets where you do not lead. They consume cash and return little, and every one of them is a decision rather than a position: invest heavily enough to contend for leadership, or exit. The expensive mistake is the middle path — funding several question marks at a level sufficient to keep them alive and insufficient to make any of them win.
Ask yourself
- Which of these could realistically reach leadership?
- What would it cost to get there, honestly?
- Which are we funding out of habit rather than conviction?
- If we can only back one, which one?
Patterns that work
- Each one needs an explicit invest-or-exit decision
- Backing all of them equally is the classic portfolio error
- Under-funded question marks become dogs when growth slows
Cash Cows — Low Growth, High Share
What generates the cash everything else spends?
Leaders in mature markets. They need relatively little investment and throw off cash that funds the rest of the portfolio. The strategy is to milk them efficiently — protect the position, keep costs down, and resist both over-investing in a market that will not grow and neglecting them until the position erodes.
Ask yourself
- Which products fund everything else?
- How much cash does each actually produce, net?
- What is the minimum needed to defend this?
- How exposed are we if this declines?
Patterns that work
- Milk efficiently: defend position, minimise investment
- Over-investing in a flat market is a common and quiet waste
- Dependence on a single cash cow is a concentration risk worth naming
Dogs — Low Growth, Low Share
What is tying up resources for little return?
Low share in a market that is not growing. Usually candidates for divestment or discontinuation, though not always: some dogs are strategically necessary because they complete a product line, serve an important customer, or feed a cash cow. The requirement is that keeping one is a stated decision with a reason, rather than an oversight.
Ask yourself
- What would happen if we discontinued this?
- Is it profitable, or merely still selling?
- Does it support something else in the portfolio?
- What is the real cost of keeping it, including attention?
Patterns that work
- Divest, discontinue, or state explicitly why you are keeping it
- Management attention is the hidden cost, not just the P&L line
- Some dogs earn their place — but only by argument, never by default
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