What is Market Share?
Market share is the proportion of a defined market’s total sales that a company holds over a period, expressed as a percentage. It can be measured by revenue or by units, and the two can tell different stories.
The figure is entirely dependent on how the market is defined. Narrow the definition and share rises; widen it and share falls. This makes market share both a genuinely useful competitive measure and one of the easiest to present favourably.
Key Takeaways
- The market definition determines the number, so it must be stated alongside it.
- Revenue share and unit share diverge when price positions differ.
- Share can rise while revenue falls if the whole market is contracting.
- Relative share against the largest competitor is often more informative than absolute share.
Understanding Market Share
The calculation is straightforward: the company’s sales divided by total market sales for the same period and definition. The difficulty is the denominator. Total market sales must come from a consistent source, and the boundary of the market must be defensible rather than chosen to flatter.
Revenue and unit share answer different questions. A premium brand may hold a large revenue share on modest volume; a value brand the reverse. Reporting only one hides the position. Reading them together indicates whether share is being bought with price.
Direction matters more than level. Share is a zero-sum measure, so a gain must come from somewhere, and tracking where it came from says more about competitive position than the headline percentage. Share gained while the market shrinks is a different situation from share gained while it grows.
Formula
Market Share = (Company Sales / Total Market Sales) x 100
Both figures must cover the same period and the same market definition. Substituting units for revenue gives unit share, which can differ substantially where price positions vary.
Real-World Example
A brand reports its share rising from twelve to fourteen per cent and treats it as a win. The market contracted eleven per cent that year, so its actual revenue fell. It gained share because two competitors withdrew, not because it performed better. The share figure was accurate and the conclusion drawn from it was wrong.
Importance in Business or Economics
Share is one of the few measures that is inherently competitive: it cannot improve without someone else’s declining. That makes it a check on internal measures such as revenue growth, which can look healthy while a business loses ground in a market growing faster than it is.
Types or Variations
- Revenue market share: Share of total market value, weighting by price.
- Unit market share: Share of total volume sold, ignoring price.
- Relative market share: The company’s share divided by that of its largest competitor.
- Served market share: Share of only the segment the company actually addresses.
Related Terms
- Market Penetration
- Strategic Planning
- Marketing Analytics
- Marketing Mix
- Digital Marketing
- Business Intelligence
Quick Reference
- Formula: (Company sales / total market sales) x 100
- Bases: Revenue or units
- Critical caveat: The market definition drives the result
- Property: Zero-sum: gains come from competitors
Frequently Asked Questions
How is market share calculated?
Divide the company’s sales by total sales in the defined market for the same period, then multiply by one hundred. Both figures must use the same basis, either revenue or units, and the same market boundary.
What is the difference between market share and market penetration?
Market share compares you to competitors within a market. Market penetration compares actual sales to the total potential of that market, including people not currently buying from anyone. A category can have high share concentration and low penetration at the same time.
Can market share rise while a business declines?
Yes, and it commonly does in contracting markets. If the market shrinks faster than the company does, share rises while revenue falls. This is why share should be read alongside absolute figures.