In 30 seconds
- Market capitalization is the share price multiplied by the number of shares outstanding.
- Coca-Cola's market cap was about $300.7 billion on December 31, 2025 ($69.91 × 4,300.7 million shares).
- A share price doesn't tell you size: Caterpillar had the most expensive share, and Nvidia was worth 17 times more.
- Market cap doesn't tell you whether a company is expensive, and it leaves out debt: that's what the P/E ratio and enterprise value are for.
Introduction
On December 31, 2025, a share of Caterpillar closed at $572.87 and a share of Nvidia at $186.50. Going by price alone, you'd say Caterpillar is the bigger company. It's the other way around: that day the stock market valued Nvidia at roughly 17 times more. A share price tells you nothing about how big a company is. Market capitalization does, and you can work it out in a minute.
Explanation
Market capitalization, or market cap, is the value the stock market puts on all of a company's shares at a given moment. In theory, it's what you'd pay to buy every single share at today's closing price.
Picture a building with 20 identical condos. If one sold yesterday for $200,000, the building is "worth" $4 million at market prices. Nobody has sold the whole building: you're stretching the last sale across every unit. The stock market does exactly that, every second, with every listed company. And if another condo sells tomorrow for $180,000, the building loses $400,000 in value without anyone touching a brick.
How to calculate it
Multiply the share price by the number of shares outstanding. The price is in any stock quote. The company reports its shares outstanding on the cover page of its annual report (Form 10-K, in the US) and on its balance sheet.
Notice the word "outstanding." Shares the company has bought back and holds as treasury stock don't count, because they don't belong to any shareholder. And if a company has several share classes, you add them all up: Alphabet has three (A, B and C), and its market cap covers all three together.
So what's it good for? It tells you the size of what you're looking at. A $2 billion company and a $2 trillion company behave very differently: the small one can double its sales with a couple of big contracts; the giant has to conquer half the world to do the same.
Formula
Market capitalization = Share price × Shares outstanding
Share price = latest closing price on the exchange
Shares outstanding = shares issued − treasury shares (10-K cover page or balance sheet)
Example
The table below compares the market cap of four companies that have nothing in common: a chipmaker (Nvidia), a bank (JPMorgan Chase), a soft-drink maker (Coca-Cola) and a heavy-equipment manufacturer (Caterpillar). Figures are in billions of dollars, so 1,000 in the table means a trillion.
Step by step: Coca-Cola on December 31, 2025
1. Closing price that day: $69.91.
2. Shares outstanding, from the cover page of its 10-K for fiscal 2025: 4,300.7 million as of February 18, 2026. The number barely moves from one month to the next.
3. Multiply: $69.91 × 4,300.7 million = $300,662 million.
4. Rounded: about $300.7 billion.
Run the same math, using the share count each 10-K reports at fiscal year-end, and you get the other three as of December 31, 2025:
Nvidia: $186.50 × 24,304 million shares = about $4.53 trillion.
JPMorgan Chase: $322.22 × 2,696.2 million = about $868.8 billion.
Caterpillar: $572.87 × 465.3 million = about $266.6 billion.
Caterpillar has the most expensive share of the four and is the smallest company. Nvidia, with a share that costs a third as much, is 17 times bigger. So when the question is size, ignore the price per share.
Before you check the table: do you think Nvidia is still worth more than JPMorgan, Coca-Cola and Caterpillar combined? At the end of 2025 those three added up to about $1.44 trillion. Check it against today's numbers.
Real-data example
| Company | Ticker | Market cap ($ billion) |
|---|---|---|
| NVIDIA Corporation | NVDA | 5,591.7 |
| JPMorgan Chase & Co. | JPM | 890.6 |
| The Coca-Cola Company | KO | 377.8 |
| Caterpillar Inc. | CAT | 373.5 |
How to read it
How to read it
Market cap sorts companies by size. These are the bands used by the size filter in Kaplio's screener:
| Size | Market cap | What it usually means |
|---|---|---|
| Mega cap | more than $100,000 million | established business, closely followed by analysts; doubling in size takes a lot |
| Large cap | $10,000-100,000 million | a leader in its niche or its home country |
| Mid cap | $2,000-10,000 million | more room to grow and a bumpier ride in the market |
| Small cap | less than $2,000 million | less analyst coverage, more risk and more mispriced stocks |
Benjamin Graham told the defensive investor to stick to companies of adequate size; Jason Zweig, in his commentary on "The Intelligent Investor," puts that floor at about $2 billion. Size also reads differently from sector to sector: for banks and insurers, market cap is compared with book value, because the balance sheet is the business; for tech and consumer companies, it's compared with earnings and cash flow.
Pitfalls and limitations
1. Watch the zeros. A billion is a thousand millions and a trillion is a thousand billions. Spanish and most European languages call a trillion a "billón," so Nvidia's $4.53 trillion shows up in Spanish-language coverage as 4.53 billones. If you ever see "$4,530 trillion," someone has mixed up the two scales and is off by a factor of a thousand.
2. Big doesn't mean expensive, or cheap. Market cap tells you how much you're paying for the whole company, not whether that's a lot or a little. For that you have to compare it with earnings, which is exactly what the P/E ratio does.
3. It can't see debt. Whoever bought the whole company would also take on its debt and its cash. That fuller number is enterprise value.
4. It changes every day. If the stock drops 10%, the market cap drops 10%, even though the business is the same one it was yesterday. It's a snapshot, not intrinsic value.
Case in point: Nvidia, where market cap followed earnings
In fiscal 2023 (which ended in January of that year), Nvidia had revenue of $26,974 million and net income of $4,368 million. In fiscal 2026, which ended on January 25, 2026, revenue was $215,938 million, and 120,067 of those millions were net income. Earnings grew 27-fold in three years, and the market made it the largest company in the world by the end of 2025. Over the long run, market cap chases earnings. In the short run, it chases whatever the market thinks is coming next.
Practice on Kaplio
Frequently asked questions
What is the meaning of market cap?
Market cap is short for market capitalization, the total value the stock market puts on a company at a given moment: the share price times the number of shares outstanding. It measures size and lets you compare companies. It isn't what the business is really worth or what it would cost to buy, since it ignores debt and cash.
How is market capitalization calculated?
Multiply the latest share price by the number of shares outstanding, which the company reports on the cover of its 10-K. Coca-Cola closed 2025 at $69.91 with 4,300.7 million shares outstanding, for a market cap of about $300.7 billion. Leave out treasury shares, and if there are several share classes, add them all up.
Is a higher market cap better?
Not by itself. A higher market cap means a bigger company, not a better investment. Giants tend to be established and closely followed, but they need enormous growth to double in size. Smaller companies carry more risk and more mispricing. Whether a stock is cheap depends on comparing its price with earnings, not on its size.
What are the 5 largest companies by market cap?
The ranking shifts with prices every day. Using December 31, 2025 closing prices and the share counts in their annual reports, Nvidia led with about $4.53 trillion, ahead of Apple (about $4.02 trillion) and Alphabet (about $3.78 trillion). For today's figures and the rest of the top five, check each company's page on Kaplio.