Stock MarketBeginner

Chapter 2 of 15

How Do BSE and NSE Work?

India's two stock exchanges — history, role, and trading.

10 min read Chapter 2

Ramesh, a retired schoolteacher in Chennai, often heard his son talk about "buying something on the NSE" and "checking the Sensex." For years he assumed Sensex and NSE were the same thing. When he finally sat down to learn the difference, he discovered that India has two major stock exchanges — each with its own benchmark index — and that understanding them is the first step to becoming a confident investor.

BSE — Bombay Stock Exchange

BSE (Bombay Stock Exchange):

Established in 1875, the BSE is Asia's oldest stock exchange, headquartered on Dalal Street in Mumbai. It lists over 5,000 companies and uses the Sensex as its benchmark index.

Asia's Oldest Stock Exchange

The BSE, founded in 1875 as the "Native Share and Stock Brokers' Association," predates India's independence by over 70 years. It was the first exchange in Asia to receive permanent recognition from the Government of India under the Securities Contracts Regulation Act, 1956.

The BSE's benchmark index is the Sensex (short for Sensitive Index), which tracks the performance of 30 large, well-established companies listed on BSE. Companies like Reliance Industries, TCS, HDFC Bank, and Infosys are part of the Sensex. When you hear "Sensex rose 600 points today," it means these 30 companies collectively became more valuable.

Sensex:

The Sensex is BSE's benchmark index comprising the 30 largest and most actively traded companies on BSE, representing various sectors of the Indian economy. It was launched on 1 January 1986.

NSE — National Stock Exchange

NSE (National Stock Exchange):

Established in 1994, the NSE was India's first fully electronic, screen-based stock exchange. It is headquartered in Mumbai and uses the Nifty 50 as its benchmark index. By trading volume, it is consistently among the world's top exchanges.

The NSE was set up specifically to address the inefficiencies of the older, floor-based BSE trading system. By introducing electronic trading, the NSE democratised stock market access — prices became transparent and uniform across the country, not just in Mumbai. Today, over 95% of India's equity trading by volume happens on the NSE.

Nifty 50:

The Nifty 50 is NSE's flagship benchmark index tracking the 50 largest and most liquid companies listed on NSE, across 13 sectors. "Nifty" is a portmanteau of "NSE" and "Fifty."

Index:

A stock market index is a statistical measure that tracks the performance of a select group of stocks, providing a snapshot of overall market or sector health. It cannot be directly bought or sold, but index funds and ETFs replicate its performance.

BSE vs NSE — A Detailed Comparison

Feature	BSE	NSE
Year Established	1875	1994
Listed Companies	5,000+	2,000+
Benchmark Index	Sensex (30 stocks)	Nifty 50 (50 stocks)
Trading System	Electronic (BOLT)	Electronic (NEAT)
Avg Daily Turnover	~₹4,000–6,000 crore (equity)	~₹60,000–90,000 crore (equity)
Derivatives Volume	Lower	World leader in F&O volume
Headquarters	Dalal Street, Mumbai	BKC, Mumbai

How Is the Nifty 50 Calculated?

The Nifty 50 uses a free-float market capitalisation weighted methodology. This means companies with higher free-float market caps have more influence on the index. The index base is 1,000, set as of November 3, 1995.

Example: How Nifty 50 Moves

Suppose the total free-float market cap of all 50 Nifty companies is ₹1,80,00,000 crore (₹180 lakh crore). If Reliance Industries — the largest Nifty constituent at ~10% weight — rises by 2%, it contributes approximately: 0.10 × 2% = 0.2% rise in Nifty 50

If Nifty is at 22,000, a 0.2% move = 44 points up. A small-cap stock at 0.1% weight rising 5% would move the Nifty by just 2.2 points. This is why Reliance news can move the Sensex or Nifty significantly while news about a smaller company barely budges the index.

SEBI — The Regulator of Indian Capital Markets

The Securities and Exchange Board of India (SEBI), established in 1988 and given statutory powers in 1992, regulates both BSE and NSE. SEBI's responsibilities include:

Protecting investor interests from fraud and manipulation
Regulating stockbrokers, mutual funds, and portfolio managers
Overseeing IPOs and ensuring fair disclosure by companies
Investigating market manipulation and insider trading

SEBI is to Indian stock markets what RBI is to banking — the ultimate authority ensuring the system functions fairly and transparently.

Trading Hours and Sessions

Indian stock markets operate on all weekdays (Monday–Friday) except national holidays. The normal equity trading session is:

Pre-open session: 9:00 AM – 9:15 AM (order collection and price discovery)
Normal trading session: 9:15 AM – 3:30 PM
Post-close session: 3:40 PM – 4:00 PM (at closing price)

Check the exchange holiday calendar

NSE and BSE publish their annual trading holiday calendars on their websites. In 2024, there were 14 trading holidays including Holi, Diwali (Muhurat Trading is a special evening session), and Republic Day.

Quick Quiz

At what time does the normal equity trading session begin on Indian stock exchanges?

Key Takeaways

BSE (est. 1875) and NSE (est. 1994) are India's two major stock exchanges — most stocks are listed on both, but NSE dominates trading volume.
Sensex tracks 30 stocks on BSE; Nifty 50 tracks 50 stocks on NSE — both are free-float market-cap weighted indices.
SEBI regulates both exchanges to protect investors and ensure market integrity.
Normal trading hours are 9:15 AM to 3:30 PM on weekdays, with a pre-open session from 9:00–9:15 AM.

Ch 1: What is the Stock Market?

Ch 3: How to Open a Demat Account