Market capitalisation is the price of one share multiplied by the number of shares in issue. It is the figure that answers a question share prices cannot: how much is this whole company worth, according to the market, right now?
Once you work in market capitalisation rather than share price, a persistent beginner's error disappears — the belief that a GH₵2 share is cheap and a GH₵40 share is expensive.
The calculation
Market capitalisation = share price × number of shares in issue
A company with 500 million shares trading at GH₵4.00 has a market capitalisation of GH₵2 billion. The market is collectively saying the entire business is worth that.
Why the share price alone tells you nothing
Consider two companies, both valued by the market at GH₵2 billion:
| Company A | Company B | |
|---|---|---|
| Share price | GH₵2.00 | GH₵40.00 |
| Shares in issue | 1,000,000,000 | 50,000,000 |
| Market capitalisation | GH₵2bn | GH₵2bn |
Neither is cheaper. They are priced identically; they have simply divided ownership into different numbers of slices. A share price is a quotient, and on its own it is close to meaningless.
What market capitalisation is used for
Sizing a company
Market capitalisation is how companies are grouped into large, mid and small. The boundaries are relative to the market in question: a company that counts as mid-sized on the Johannesburg Stock Exchange would be among the largest on the Ghana Stock Exchange. Size matters because it correlates with liquidity, analyst coverage and how violently the price moves.
Weighting an index
Most headline indices are market-capitalisation weighted, which means the largest companies move the index most. The GSE Composite Index is built this way, as is the GSE Financial Stocks Index. A 2% move in the largest listing shifts the index more than a 10% move in a small one — so an index can rise on a day when most shares fell. We explain this in the GSE indices explained.
Comparing whole markets
Adding up the market capitalisation of every listed company gives a market's total size, which is how exchanges are ranked against one another. It is also compared with a country's GDP to gauge how much of the economy is actually listed. See Africa's largest exchanges.
Valuing the business, properly
This is the most useful application. Set market capitalisation against what the company produces:
- Price-to-earnings — market capitalisation ÷ annual profit. Roughly, how many years of current profit you are paying for.
- Price-to-book — market capitalisation ÷ net assets. Whether you are paying above or below the accounting value of what the company owns.
- Price-to-sales — useful for companies that are growing but not yet profitable.
These ratios are comparable between companies in a way share prices never are.
Enterprise value: the number market capitalisation leaves out
Market capitalisation is the value of the equity. It ignores debt — and if you were buying the whole company, you would inherit the debt.
Enterprise value = market capitalisation + total debt − cash
Two companies with identical market capitalisations are not equally priced if one carries heavy borrowings and the other holds net cash. For capital-intensive businesses, enterprise value is the more honest measure. Our guide to analysing financial statements covers finding the debt and cash figures.
Free float: the shares you can actually buy
This matters a great deal on African exchanges. Headline market capitalisation counts every share in issue, including those held by a founding family, a parent company or the state — shares that will never trade.
Free-float market capitalisation counts only the portion genuinely available to the public. A company with a GH₵5bn headline capitalisation and a 15% free float has only GH₵750m of tradeable stock. The consequences are practical:
- The price can move sharply on modest volume.
- Entering or exiting a position of any size is difficult.
- The company looks more significant in the market than its actual tradeable weight warrants.
Check the volume column on the live GSE board before assuming you can transact in a large listing. Size and liquidity are not the same thing.
What market capitalisation does not tell you
Whether the company is any good. It reflects what the market currently believes, and markets are sometimes wrong in both directions.
Whether it is cheap. A large capitalisation is not expensive and a small one is not a bargain. Only the relationship between capitalisation and the underlying business tells you about value.
What you would receive in a liquidation. That is closer to net asset value, and for most companies the two differ substantially.
How it will change. Capitalisation moves with price every second the market is open, and also changes when a company issues new shares or buys them back — which is why per-share figures deserve attention alongside company-level totals.
A worked example
Suppose a listed bank has 2.5 billion shares at GH₵3.20, annual profit of GH₵900 million, and net assets of GH₵4.5 billion.
- Market capitalisation: 2.5bn × GH₵3.20 = GH₵8.0bn
- Price-to-earnings: 8.0 ÷ 0.9 = 8.9×
- Price-to-book: 8.0 ÷ 4.5 = 1.78×
Now the figures mean something. You can compare that 8.9× against other listed banks, against the bank's own history, and against banks on the NGX or the JSE. The GH₵3.20 share price, by itself, permitted none of that.
Frequently asked questions
Where do I find a company's market capitalisation?
Multiply the current share price by the shares in issue, which appears in the annual report. Exchanges and data providers also publish it directly.
Does market capitalisation change when a company pays a dividend?
Indirectly. Cash leaves the business, and share prices typically adjust downward around the ex-dividend date, which reduces capitalisation. The shareholder has the cash instead.
Is a bigger company a safer investment?
Larger companies tend to be more diversified and more liquid, which reduces certain risks. They are not immune to permanent loss, and size has never prevented a business from being overpriced.
In short
Market capitalisation converts a share price into a company value, which is the unit in which comparison becomes possible. Add debt to get enterprise value, check the free float to see what is really tradeable, and then relate the figure to earnings and assets. The share price on its own is the least informative number on the screen.