Home Learn What is the Stock Market Index & How Does it Work?

What is the Stock Market Index & How Does it Work?

What is the Stock Market Index & How Does it Work?
Reading Time: 8 minutes

Have you ever heard of the term “stock market index”? 

Well, it’s like a weather report for the financial world, giving you a snapshot of how the market is doing at any given time. However, it’s not just a number to keep an eye on because when it comes to investing, understanding stock market indices can help you make better decisions. 

In this blog, we’ll take a closer look at what stock market indices are, how they work, and why they matter to you as an investor.

What is Stock Market Index?

Stock Market Index meaning is a measure of the performance of a group of stocks representing a particular market or sector. They are a statistical composite of the underlying stocks that comprise them, and they provide a benchmark against which the performance of individual stocks or portfolios can be compared. Now that we know what is stock market indices, let us also learn the importance of stock market indices.

What is the Usage of Stock Market Indices?

Stock market indices are used to track the overall performance of a particular market or a specific segment of the market. They provide investors with a benchmark against which they can measure the performance of their portfolio. 

For example, the Nifty 50 index in India tracks the performance of the top 50 companies listed on the National Stock Exchange (NSE), while the S&P 500 global stock market index in the US tracks the performance of 500 large-cap companies listed on the New York Stock Exchange (NYSE) or the Nasdaq.

How Do They Work?

Stock market indices work by aggregating the prices of a group of stocks and calculating a single number that represents the performance of that group. This calculation can be done using different methods such as price-weighted, market capitalization-weighted, equal-weighted, or fundamental-weighted indices. 

The value of the index changes in real time throughout the trading day as stock trading involves the prices of the underlying stocks fluctuating. You can use indices as a tool to track the overall performance of the market or a particular sector and make investment in share market basics and decisions based on the trends they observe.

How are Stock Market Indices Created?

Creating a stock market index involves grouping similar stocks based on market capitalization, company size, or industry. The index value is then computed, taking into account the selected stocks. However, since each stock has a different price and price change, a straightforward sum of stock prices doesn’t determine the index value. To address this, stocks are assigned weights based on factors like market price or market capitalization.

These weights signify the impact of stock price changes on the index value. The two most common types of stock market indices are:

Market-Cap Weightage

Market capitalization is the total market value of a company in the stock exchange, calculated by multiplying outstanding stocks by the share price. Stocks are selected based on their market capitalization relative to the total index market capitalization. Investors should note that a stock’s market capitalization fluctuates with its daily price changes, leading to daily changes in stock weightage.

Some indices in India employ Free-float market capitalization, where the total shares listed are not used. Instead, the number of shares available for public trading is considered.

Price Weightage

This method measures the index value based on market capitalization rather than stock prices. Higher-priced stocks receive more weightage than lower-priced ones.

Why are They Useful for You?

Indices help investors to understand the overall trend of the market, whether it is bullish or bearish. They provide a broad view of the overall market performance and trends. And help investors like you gauge the market sentiment and direction, allowing you to make informed investment decisions. 

By tracking a benchmark index, you can also measure their portfolio’s performance and compare it against the market. Therefore, investors can use the stock market indices as a reference point to assess the performance of their portfolio. They can also make adjustments as needed.
Moreover, they are also used by traders to identify potential trading in stock market opportunities. By analysts, to forecast market trends and make investment recommendations. Indices are also used as a basis for creating financial products such as index funds and exchange-traded funds (ETFs).

Types of Stock Market Indices in India

Stock market indices can be classified into different types based on the methodology used to calculate the index. Here are some common types of stock market indices:

Price Weighted Index

This type of index gives more weightage to stocks with higher prices. The stock with the highest price gets the highest weightage, and its price movements have a greater impact on the index. Examples of price-weighted indices include the Dow Jones Industrial Average (DJIA).

Market Capitalization Weighted Index

In this type of index, the weightage of each stock is based on its market capitalization. The larger the market capitalization of a stock, the higher its weightage in the index. Examples of market capitalization-weighted indices include the NIFTY 50, BSE Sensex, and S&P 500.

Equal Weighted Index

This type of index gives equal weightage to all the stocks in the index. It does not consider the market capitalization or price of the stocks. Examples of equal-weighted indices include the S&P 500. It’s a global stock market index. 

Fundamental Weighted Index

In this type of index, the weightage of each stock is based on its stock fundamentals factors such as earnings, dividends, book value, and cash flow. The stocks with higher fundamentals have a higher weightage in the index. Examples of fundamental-weighted indices include the Russell Fundamental Index (a global stock market index).

Major Stock Market Indices in India

Now that we know what are stock market indices, let’s look at the major stock market indices in India. 


NIFTY 50 is a market capitalization-weighted index of 50 companies listed on the National Stock Exchange (NSE) in India. It is considered as the benchmark index for the Indian equity market.

BSE Sensex

BSE Sensex is a market-capitalization-weighted index of 30 well-established and financially sound companies listed on the Bombay Stock Exchange (BSE) in India. It is the oldest index in India and is widely followed as a barometer of the Indian equity market.


The NIFTY 500 is a broad-based index of 500 companies listed on the National Stock Exchange in India. It represents around 96% of the total market capitalization of the companies listed on the NSE.

NIFTY Next 50

NIFTY Next 50 is a market-capitalization-weighted index of the 50 companies listed after the top 50 companies on the National Stock Exchange in India. It is considered a potential source of future market leaders and is also referred to as the junior NIFTY.

Some of the global market indices are as follows: 

  • NIKKEI 225
  • Hang Seng Index
  • CAC 40
  • VIX
  • FTSE 100 Index
  • Dow Jones Industrial Average

Let us now learn how to invest in share market online and explore a few important share market tips for beginners.

How to Invest in Stock Market via smallcase?

smallcase is a platform that offers ready-made diversified portfolios of stocks or exchange-traded funds (ETFs). These portfolios are designed and managed by professional portfolio managers, and investors can buy and sell them just like individual stocks.

How Investing via smallcase Is Better Than Traditional Investing?

smallcase offers several advantages over traditional ways of investing in the stock market for beginners. A few of them are as follows: 

  • Firstly, it offers a diversified portfolio of stocks or ETFs based on a specific theme or strategy, reducing the risk of investing in individual stocks. 
  • Secondly, smallcase offers transparency and flexibility, as investors can see the stocks or ETFs included in the portfolio and make changes as per their preferences. 
  • Finally, smallcase charges a low fee for managing the portfolios, making it affordable for retail investors.

Isn’t it amazing? Let us now learn how to trade stocks via smallcase. We know you are nodding your head. So, now let’s just understand the step-by-step process to start investing in stocks via smallcases.

1: Create an account on smallcase

2: Choose a portfolio 

3: Check the portfolio details 

4: Add funds to your smallcase account 

5: Invest in the portfolio

6: Monitor your portfolio

That’s all you need to invest via smallcase and watch your wealth grow!

Now that we know how to invest in stocks market Indices, let’s explore a few factors that affect stock market indices. 

What Factors Affect Stock Market Indices?

The factors that can affect stock market indices include:

  • Economic conditions: The state of the economy, including factors like inflation, interest rates, GDP growth, and employment levels, can have a significant impact on stock market indices.
  • Corporate earnings: The earnings of individual companies can impact the stock market indices, as investors often use earnings reports to assess the overall health of a company and make investment decisions accordingly.
  • Political events: Political events such as elections, changes in government policies, and geopolitical tensions can have a significant impact on stock market indices.
  • Global market trends: The stock market indices can also be influenced by global market trends, such as the performance of other stock markets around the world, currency exchange rates, and commodity prices.

Now that we know what is market index and the factors that influence these indices, let’s take a look at the the benefits and drawbacks of of investing in stock market indices.

What are the Advantages of Investing in the Stock Market Indices?

  • Diversification: Stock market indices are composed of many stocks, providing investors with diversification across various sectors and industries. This diversification can help reduce overall portfolio risk. As losses in one trading stock can be offset by gains in another.
  • Low Cost: Stock market investing for beginners in stock market indices is typically less expensive than investing in individual stocks. As index funds and exchange-traded funds (ETFs) have lower fees and expenses. This can help investors keep more of their investment returns.
  • Market Performance: Stock market indices generally reflect the trading information. They also reflect the performance of the overall market, which tends to increase over time. As a result, investing in indices can provide investors with exposure to the growth potential of the stock market basics of trading as a whole, rather than relying on the performance of individual stocks.

What is the Importance of Stock Market Indices?

Stock market indices stand as paramount metrics within the realm of finance and investing. These figures, widely recognized and extensively followed, hold immense significance in the global financial landscape. Investors leverage these indices as fundamental tools for monitoring and managing their investment portfolios. The pervasive use of market indices in the investment management sector underscores their deep integration into the fabric of financial decision-making.

Beyond mere tracking, these indices serve a pivotal role in performance evaluation. Investment funds routinely employ them as benchmarks, facilitating comprehensive comparisons to gauge their own financial standing and effectiveness. The symbiotic relationship between investors, market indices, and investment portfolios underscores the interconnected nature of the financial world, where these indices play a vital role in shaping strategies and determining success.

Are There Any Disadvantages of Investing in the Stock Market Indices?

Yes, investing in stock market indices comes with its own set of disadvantages. Some of them are as follows:

  • Limited flexibility: Stock market indices have a pre-determined composition of stocks, which means that investors have limited control over the individual stocks in their portfolio. This lack of flexibility can be a disadvantage for investors who prefer a more active approach to investing or are new to investing.
  • Overexposure to certain sectors: Certain sectors may have a larger representation in a particular stock market index. This can lead to overexposure to those sectors. For example, if a particular index has a large weighting towards the technology sector, then investors in that index may be overly exposed to the performance of tech companies.
  • Market volatility: Investing basics in stock market indices can be subject to market volatility and fluctuations. While the long-term trend of the market has historically been upward, short-term fluctuations can be unsettling for investors who are not comfortable with the inherent risk of stock investing in the stock market.

Why are Stock Market Indices Required?

Stock market indices play a vital role in quickly tracking stock or market performance. They serve multiple purposes:

  • Benchmarking: Investors use stock market indices as benchmarks to assess their investment or mutual fund performance. Comparing returns to relevant indices helps identify areas for improvement.
  • Market analysis: Financial analysts and traders rely on indices to gauge the market’s health and identify trends. Changes in an index over time inform whether the market is bullish or bearish, guiding informed investment decisions.
  • Diversification: Stock market indices simplify portfolio diversification. Investing in an index fund or ETF tracking a specific index provides exposure to various stocks with minimal effort and low fees.
  • News and media: Widely covered, stock market indices serve as essential tools for investors to stay informed about market developments. They offer a convenient shorthand for journalists and analysts to report on economic changes and market movements.

Formation of Stock Market Index

A stock market index s is typically formed by selecting a basket of stocks that represent a particular segment of the market, such as large-cap stocks, small-cap stocks, or a specific industry or sector. The stocks are selected based on various criteria, such as market capitalization, liquidity, trading volume, and sector classification. 

The selected stocks are then weighted based on a certain methodology, such as market capitalization weighting or equal weighting. The index is calculated by taking the weighted average of the stock prices and tracking the changes in the index over time. The stocks within the index are periodically reviewed and updated to ensure that the index remains representative of the market segment it is intended to track.

What are Sectoral Indices?

Sectoral indices are stock market indices that track the performance of specific sectors or industries within an economy. In other words, they measure the performance of a group of companies operating in a particular sector or industry. 

Some of the sectoral indices in India are as follows: 

  • NIFTY Bank Index / FINNIFTY
  • NIFTY Pharma Index
  • NIFTY IT Index

Sectoral indices are useful for investors who want to invest in a specific sector or industry. This is because they provide a way to track the performance of that particular sector. They also provide a way for investors to diversify their portfolios across multiple sectors and industries.

What is World Stock Market Index? 

The world stock market index refers to the compilation of a basket of stocks from multiple countries across the globe. It represents the overall performance of the global stock market. Thereby allowing investors to gauge the trend and direction of the market on a global scale. 

Examples of world stock market indices include MSCI World Index, FTSE All-World Index, and S&P Global 100 Index. These indices are the answer to how to invest in the US stock market as well as worldwide. 

What are Stock Index Futures?

Stock index futures are contracts that allow investors to buy or sell a specific stock market index at a future date and at a predetermined price. These world major indices futures contracts are based on an underlying stock market index. Such as the S&P 500 or the NASDAQ, and are traded on futures exchanges. 

The value of the stock index futures contract is derived from the performance of the underlying stock market index. Investors can use stock index futures to speculate on the direction of the market. They can also be used to hedge against potential losses in their portfolios.

To Wrap It Up…

The stock market indices play a crucial role in tracking the overall performance of the stock market. Understanding the different types of indices and the factors that affect them can help you make informed investment decisions and achieve your financial goals. 

Moreover, investing via smallcase can be an efficient and convenient way to build a diversified portfolio with low cost and effort. So, what are you waiting for? Download the smallcase app today and begin your investment journey and learn about investing with smallcase today!


1. What is index in stock market?

An index comprises stocks, derivatives, or financial instruments. Thereby serving to gauge and reflect the performance of a specific market, asset class, sector, or investment approach. They essential metrics when it comes to understanding market fluctuations and such.

2. What does a market index indicate?

Stock market indexes enable investors to track market or sector performance, aiding in well-informed investment decisions rooted in market trends and historical data.

3. What is the index of NSE?

NSE Indices Limited, formerly known as India Index Services & Products Limited, owns and operates the Nifty 50. It is a specialized Indian company with a primary focus on index management.

4. Which are the major stock market indices in India?

In India, the BSE Sensex and NSE Nifty serve as key indicators for trading for beginners, reflecting overall market performance. Additionally, sectoral indices like the BSE Bankex and CNX IT provide insights into specific industries. Experts see further categorization in indices like BSE Smallcap and BSE Midcap, based on market capitalization.

5. What is Nifty full form?

NIFTY is short for National Stock Exchange FIFTY.

6. How are stock market indices calculated?

Benchmark indices gauge market performance by monitoring specific stock prices, often the top 30 or 50 in terms of value. Calculated through predetermined criteria like price-weighted or market-cap weighted averages, these indices provide a snapshot of overall market trends.

All About Investment Concepts on smallcase –

smallcase offers you a quick view to the different finance related concepts to help you on your investment journey to achieve the financial freedom you have always dreamt of –