Free float is the portion of a company's shares that is actually available for public trading, after excluding promoter holdings, government stakes, and other locked-in shares. Indian indices such as the Nifty 50 and Sensex weight each company by its free-float market capitalisation, not its total market cap, so a company's influence on the index reflects tradable shares, not shares held tightly by insiders.
Key takeaways
- Free float is total shares minus locked-in shares such as promoter, government, and strategic holdings.
- Free-float market cap equals share price multiplied by only the freely tradable shares.
- The Nifty 50 and Sensex are free-float weighted, so index weight reflects tradable value, not total company size.
- A company with a large promoter stake carries less index weight than its total market cap alone would suggest.
What is free float, in plain terms?
Free float is the slice of a company's shares that is genuinely available for the public to buy and sell. Not every share a company has issued trades freely. Promoters (the founding owners), the government in state-run firms, and strategic investors often hold large blocks they do not sell, and some shares are contractually locked for a period.
Free float removes those tightly held shares from the count. If a company has issued one billion shares but promoters hold 600 million that never come to market, only the remaining 400 million make up its free float. That 40 percent is the portion that actually sets the price through supply and demand.
How is free-float market cap calculated?
Ordinary Market Cap is the share price multiplied by the total number of shares outstanding. Free-float market cap uses the same price but multiplies it by only the freely tradable shares.
The exchange applies an investable weight factor (IWF), a number between zero and one that represents the proportion of shares in free float. A company with 40 percent free float has an IWF of 0.40, so its free-float market cap is its full market cap multiplied by 0.40. For a company priced at 1,000 rupees with one billion shares, the total market cap is 1,000 billion rupees, but if only 40 percent is free float, its free-float market cap is 400 billion rupees.
Explore index and fund data on Artha Terminal to see how free-float weighting shapes the Nifty 50, the Sensex, and the funds that track them.
Why do indices use free float instead of total market cap?
An Index such as the Nifty 50 or the Sensex is meant to represent the value that investors can actually access in the market. Weighting by total market cap would overstate the importance of companies with large, immovable promoter stakes, because most of those shares never trade and so cannot influence real supply and demand.
By weighting each company by free-float market cap, the index reflects tradable value. A company with a 75 percent promoter holding contributes far less weight than a company of the same total size whose shares are widely dispersed. This makes the index a more honest gauge of the investable market and a fairer benchmark for an Index Fund that has to buy the shares in the same proportions.
How does free float change a company's index weight?
Two companies can have identical total market caps yet very different index weights. Suppose both are worth 500 billion rupees in total. One has 30 percent free float and the other has 70 percent. The first contributes 150 billion rupees of free-float market cap to the index; the second contributes 350 billion. The second company will therefore carry more than twice the index weight, despite the two being the same size overall.
This is why a widely held private-sector bank can outweigh a larger state-run company in the Sensex. Free float, not headline size, drives the weighting. It also means that when a promoter sells a block of shares and free float rises, a company's index weight can increase even if its price has not moved.
How can you see free float and its effect on Artha Terminal?
On Artha Terminal, index and stock pages let you see how companies are weighted and how the broad indices are built from their constituents, so the abstract idea of free-float weighting becomes concrete. You can compare a company's total size with the share of it that actually drives its index influence.
If a weighting looks surprising, Ask Warren can explain why a company's index weight differs from its total market cap, tying the number back to its free float. Reading this alongside Why market cap differs helps explain why different sources can quote different market-cap and weighting figures for the same company.