Editor’s note: This is general educational information about how Indian market capitalisation categories are defined. It is not investment advice, it does not recommend any security or scheme, and it is based on the official sources listed at the end.
Analysis: what the design achieves and what it does not
The choice of a rank based definition over a rupee threshold solves a specific problem. A fixed cut-off, say a set number of crore rupees, drifts out of date as prices and the size of the market change, and would need periodic revision by the regulator, with every revision reclassifying a batch of companies by administrative decision. Ranking removes that discretion. The categories keep the same population sizes, one hundred large caps and one hundred and fifty mid caps, whatever the market does, and the boundary value adjusts by itself.
The cost of that design is that category membership is relative and therefore mechanically unstable at the edges. A company sitting near the 100th or 250th position can cross the line because of the performance of other companies rather than its own, and the six month averaging window is what limits how often that happens. It is also why the rebalancing rule exists: an update to the list can force schemes to buy or sell stocks for reasons unrelated to any view on those stocks, and the one month window sets how quickly that must happen.
Two consequences follow for anyone reading a scheme’s disclosures. First, the minimum allocations are floors, not descriptions. A Large Cap Fund holding 80% in large caps has the remaining fifth to place elsewhere, and a Flexi Cap Fund with a 65% equity minimum can look like a large cap fund in one period and a mid cap fund in another without breaching anything. Second, the segment labels describe a rank, not a risk level or a size in absolute terms. The 251st company in India by full market capitalisation is a small cap by this definition regardless of how large it would look in another market or in another year.
Anyone comparing a fund against an index should check which capitalisation measure the index uses, because a free float index and the AMFI list can disagree about where a company belongs. SEBI’s own investor education material on the basics of different asset classes puts stocks alongside real estate and precious metals as one of several avenues it expects a retail investor to understand before committing money, and in the case of a stock the classification doing most of the work behind the scenes is a list that is rewritten twice a year.
What the documents say
In India, large cap, mid cap and small cap are not adjectives. They are positions in a ranked list. The Securities and Exchange Board of India fixes the boundaries by rank rather than by rupee value, and the list that assigns each stock its rank is rebuilt twice a year. A company can move from one category to another without its business changing at all, simply because other companies moved past it.
The definition is a ranking, not a threshold
SEBI’s master circular for mutual funds sets out the definition for the investment universe of equity schemes. Large cap means the 1st to 100th entities in terms of full market capitalization. Mid cap means the 101st to 250th entities. Small cap means the 251st entity onwards. There is no rupee figure anywhere in the definition, which is why the boundary between mid and small cap moves with the market rather than with any decision by the regulator.
The list itself is prepared by the Association of Mutual Funds in India, and mutual funds are required to adopt it. The rules for building it are specified. Where a stock or REIT is listed on more than one recognised exchange, an average of the full market capitalisation across those exchanges is computed; where it is listed on only one, that exchange’s figure is used. The consolidated list uses the average full market capitalisation of the previous six months rather than a single day’s snapshot. It is uploaded on the AMFI website and updated every six months on data as at the end of June and December each year, and must be available within 5 calendar days of the end of each six month period. To accommodate newly listed stocks and listings arising from schemes of arrangement such as demergers between those cycles, AMFI prepares a list on a monthly basis.
Why the ranking has consequences
The categories matter because SEBI’s scheme categorisation rules are written in terms of them. A Large Cap Fund must hold a minimum of 80% of total assets in equity and equity related instruments of large cap companies. A Mid Cap Fund and a Small Cap Fund must each hold a minimum of 65% of total assets in their respective segments. A Large and Mid Cap Fund must hold at least 35% in each of the two. A Multi Cap Fund must hold a minimum of 75% of total assets in equity, made up of at least 25% each in large cap, mid cap and small cap companies.
A Flexi Cap Fund must hold a minimum of 65% in equity but is free to move across the three segments. A Focused Fund is limited to a maximum of 30 stocks and must state which segment it intends to focus on.
Because the mandates are written against the list, a change in the list is an instruction to trade. When the list is updated, mutual funds must rebalance their portfolios in line with the updated list within a period of one month. Only one scheme per category is permitted, with exceptions for index funds and exchange traded funds tracking different indices, funds of funds with different underlying schemes, and sectoral or thematic funds covering different sectors. A passive equity linked saving scheme, offered through an index fund, must be based on an index comprising equity shares from the top 250 companies by market capitalisation, which is the same boundary drawn a different way.
Full market capitalisation, not free float
The measure named in the definition is full market capitalisation, meaning the entire issued share capital at market price, rather than the free float capitalisation used by many index providers, which counts only shares available to the public. The distinction matters most for companies with concentrated promoter or government holdings. A company where promoters hold a large majority ranks higher on a full capitalisation basis than on a free float basis, so a stock can be a large cap for the purposes of a mutual fund mandate while carrying a much smaller weight, or none at all, in a free float weighted index.
Nothing in the SEBI (Mutual Funds) Regulations, 2026 leaves the classification to the asset management company. The scheme’s characteristics, including the segment it must invest in, are disclosed in the scheme information document and the statement of additional information, and it is the AMFI list that determines which companies satisfy them.
