What is market cap? Market capitalisation is the total value the stock market places on a company’s shares. You calculate it by multiplying the current share price by the number of shares outstanding. Therefore, it tells you how big a company is in the eyes of investors.
However, market cap does not equal profit, revenue or book value. This guide explains the formula, the SEBI-based categories, the free float version and the traps. Related explainers live in our Shareholding & Fundamentals category.
Quick answer: Market capitalisation equals the current share price multiplied by the total number of outstanding shares. A company with 100 crore shares trading at Rs 200 has a market cap of Rs 20,000 crore. In India, the top 100 listed companies by market cap are large caps.
Key Takeaways
- Market cap = share price × shares outstanding.
- SEBI defines large caps as ranks 1 to 100, mid caps as 101 to 250 and small caps as 251 onwards.
- AMFI publishes the classification list twice a year, in January and July.
- Free float market cap counts only shares available for public trading.
- Market cap shows size, not quality or value.
What Is Market Cap? A Simple Definition
A company issues shares to raise money. Investors buy and sell those shares every day. The market cap adds up the value of all the shares at the current price.
For example, if a company has 50 crore shares and each trades at Rs 400, the market cap is Rs 20,000 crore. If the price rises to Rs 440, the market cap rises to Rs 22,000 crore. Consequently, market cap changes every second the market is open.
Market Cap Formula and Example
| Item | Value |
|---|---|
| Shares outstanding | 80 crore |
| Share price | Rs 250 |
| Market cap | 80 crore × Rs 250 = Rs 20,000 crore |
| After a 10 percent price rise | Rs 22,000 crore |
The numbers above are examples only. Moreover, shares outstanding exclude treasury shares and include all classes that trade. After a split or bonus, the share count changes, but the market cap stays the same because the price adjusts.
Large Cap, Mid Cap and Small Cap in India
| Category | Rank by full market cap | General profile |
|---|---|---|
| Large cap | 1 to 100 | Established, liquid companies |
| Mid cap | 101 to 250 | Growing companies with more risk |
| Small cap | 251 and below | Smaller, less liquid, more volatile |
SEBI introduced uniform definitions in 2017 so that every equity fund uses the same yardstick. The split depends on rank, not a fixed rupee amount. Therefore, the rupee cut-offs move as the market rises and falls. AMFI publishes the list in January and July, based on average market cap over the previous six months. Check the latest list on the AMFI website.
Full Market Cap vs Free Float Market Cap
Promoters and strategic holders often keep their shares for the long term. Those shares rarely trade. Free float market cap removes them and counts only shares available to the public.
| Measure | Shares counted | Used for |
|---|---|---|
| Full market cap | All outstanding shares | Mutual fund categorisation by SEBI and AMFI |
| Free float market cap | Shares available for public trading | Index weights such as the Nifty 50 |
Our shareholding pattern guide shows how to find promoter and public holdings. Additionally, the FII and DII page explains who the large institutional holders are.
Why Market Cap Matters to Investors
- Risk profile: Large caps tend to be more stable, while small caps swing more.
- Liquidity: Large caps trade in high volumes, so you can enter and exit easily.
- Index inclusion: Index funds buy members of indices like the Nifty 50.
- Portfolio balance: Mixing sizes spreads risk across the market.
Market Cap vs Other Measures
| Measure | What it shows | Limitation |
|---|---|---|
| Market cap | Total market value of equity | Ignores debt and profit |
| Enterprise value | Market cap plus net debt | Needs balance sheet data |
| Book value | Net assets on the balance sheet | Based on accounting, not market views |
| Revenue | Sales earned | Says nothing about profit or price |
Market cap says what the market thinks, whereas book value says what the books show. Similarly, the PE ratio links price to profit. Read our PE ratio meaning guide to combine them.
How to Find a Company’s Market Cap
- Open the company page on the NSE or BSE website or a reliable data provider.
- Look for market capitalisation in the key statistics section.
- Check the date, because the value changes daily.
- Compare with peers in the same sector.
- Cross-check the share count in the latest shareholding pattern filing.
Free sites sometimes display stale figures. Therefore, always verify with the exchange. You can check data on the NSE and BSE.
How Corporate Actions Change the Numbers
| Action | Share count | Share price | Market cap |
|---|---|---|---|
| Stock split (1:5) | Rises five times | Falls to one fifth | Unchanged |
| Bonus issue (1:1) | Doubles | Adjusts to about half | Unchanged |
| Buyback | Falls | Often supported | Falls by the cash returned |
| Fresh share issue | Rises | May dip on dilution | Rises by money raised |
| Rights issue | Rises | Adjusts for the discount | Rises by money raised |
Notice that only actions involving cash change the market cap. Splits and bonus issues only relabel the pie. Therefore, a lower post-split price never means a smaller company. Our guide on the Adani Power stock split shows a split in action.
Mega Cap, Micro Cap and Other Labels
Beyond the SEBI categories, analysts use informal labels. Mega cap describes the very largest companies in an index. Micro cap describes tiny listed companies, often with thin trading. Neither term has an official definition in India, so treat them as loose descriptions.
Micro caps deserve extra caution. Low volumes make prices easy to move, and information is sparse. Consequently, many advisers suggest keeping exposure small and diversified.
How Mutual Funds Use Market Cap Categories
| Fund type | Minimum equity exposure to its category (SEBI norm) |
|---|---|
| Large cap fund | At least 80 percent in large cap stocks |
| Mid cap fund | At least 65 percent in mid cap stocks |
| Small cap fund | At least 65 percent in small cap stocks |
| Flexi cap fund | At least 65 percent in equity, with no size restriction |
These thresholds explain why fund portfolios shift when AMFI updates its list. A stock that drops from large to mid cap forces large cap funds to sell it. Likewise, a stock that rises into the large cap list gains new buyers. Always check the latest SEBI circular for exact limits.
Expert Insights: Using Market Cap in Real Decisions
First, treat market cap as a size label, not a quality label. A large company can still be overvalued, and a small company can be a quality business. Second, use market cap to set position sizes. Many investors keep small caps to a limited share of their portfolio because they swing harder.
Third, watch for share count changes. A buyback shrinks the count, while new issues expand it. For a real-world example, read our Infosys buyback record date guide.
Common Mistakes About Market Cap
- Assuming a high share price means a large market cap.
- Comparing share prices across companies instead of market caps.
- Ignoring that classification lists change twice a year.
- Treating a large cap as risk-free.
- Using an outdated market cap figure in valuation work.
Frequently Asked Questions
What is market cap in simple words?
Market cap is the total value of all a company’s shares at the current price. It equals share price multiplied by shares outstanding.
How is market cap calculated?
Multiply the current market price of one share by the total number of outstanding shares. For example, 100 crore shares at Rs 200 gives Rs 20,000 crore.
What are large, mid and small caps in India?
SEBI ranks listed companies by full market cap. The top 100 are large caps, ranks 101 to 250 are mid caps and the rest are small caps.
Who updates the market cap classification?
AMFI publishes the list in consultation with SEBI and the exchanges, usually in January and July, using average market cap over six months.
What is free float market cap?
It counts only shares available for public trading and excludes promoter and strategic holdings. Index providers use it to set index weights.
Does a higher share price mean a bigger company?
No. Company size depends on price times share count. A company with a low price and many shares can be larger than one with a high price and few shares.
Does a stock split change market cap?
No. A split raises the share count and lowers the price proportionally, so the market cap stays the same.
Applying What Is Market Cap Knowledge to Your Portfolio
Now that you know what is market cap, use it to understand size, risk and fund categories, not to judge value alone. Check the latest AMFI list, compare companies by market cap and keep valuation tools like the PE ratio beside it. Explore more guides on Investor Weekly News. This article is educational and not investment advice.
Trending Now
- Government Shareholding in SBI: Full Breakdown 2026
- Titan Company Promoter Shareholding Analysis June 2026 — Pledged Shares and Insider Signals
- Maruti Suzuki Promoter Shareholding Analysis May 2026 — Pledged Shares and Insider Signals
- Best NBFC Stocks India June 2026 — Bajaj Finance vs Peers Complete Comparison
- 15 Highest Dividend Paying Stocks in India (2026 List)
Disclaimer: Investor Weekly News is an independent, informational website. We are not affiliated with any company, broker, stock exchange, or regulator named in this article. Nothing here is investment, tax, or legal advice. Always confirm dates and terms in the official NSE, BSE, or company announcement before you act.
Written by
Sarita is a Senior Analyst and Lead Contributor at InvestorWeeklyNews. As a commerce postgraduate, she specializes in deep-dive analysis of financial instruments, including the Nifty 50, Gold ETFs, and RBI bonds. Sarita combines her academic expertise with a passion for wealth management to provide practical, everyday-use financial insights for modern investors.