Have you ever used Zerodha or Groww, checked a share price and found a slightly different figure on another platform or on the BSE website? Like, for instance, the price of Reliance at ₹2,845.10 on NSE and ₹2,845.60 on BSE at the same time?
Your app is not malfunctioning. Even, nobody is cheating you. It is completely normal to see different prices in stock markets. Let’s understand the reasons behind this.
First, the basics: NSE and BSE are two separate "shops"
Think of it like this, imagine the same brand of sneakers being sold in two different shops on the same street. Shop A (NSE) and Shop B (BSE) both sell the exact same sneakers. But:
- Shop A has way more customers walking in and out
- Shop B has fewer customers
- Each shop sets its price based on its own buyers and sellers, not what’s happening in the other shop
That’s basically NSE and BSE. They’re two completely separate exchanges with their own separate order books (order book = the list of everyone wanting to buy or sell at a given moment). A buy/sell order on NSE doesn’t “see” what’s happening on BSE, and vice versa. So the price on each one is decided independently, moment to moment, by whoever’s trading there.
That’s reason #1, right there: different buyers and sellers = slightly different prices.
Reason 2: NSE is just way bigger
The NSE is recognized as the leading exchange in India with the highest share of trading volume. The BSE accounts for only a small portion of the overall trading volume.
What are the implications of this?
There are numerous buy and sell orders at every price level on the NSE. This means that even large orders like those of individuals, institutions, or traders do not significantly move prices. Such orders do not have much weight in moving stocks significantly in any way.
In contrast, there are much fewer orders on the BSE, and this lets such orders move prices quite a lot.
As a result, we see that either for a large liquid stock like Reliance Industries ltd. or HDFC bank, the price difference between NSE and BSE is pretty small, about a few paise. On the other hand, for a small unknown stock, the price difference can be substantial, exceeding a rupee every now and then.
Reason 3: Arbitrage traders are basically "price police"
Okay so if NSE and BSE can have different prices, why doesn’t the gap just keep growing forever?
Because of arbitrage traders (often algo/HFT firms with super fast systems). Here’s the trick they pull:
- They notice Reliance is ₹2,845.60 on BSE but only ₹2,845.10 on NSE.
- They instantly buy on NSE (cheaper) and sell on BSE (pricier), pocketing the ₹0.50 difference.
- This buying pressure on NSE pushes its price up, and the selling pressure on BSE pushes its price down.
- The gap shrinks, fast.
This happens in milliseconds for big liquid stocks, which is why the gap rarely gets big or stays big for long on those. But it’s not instant, there’s a tiny delay, and arbitrage only happens if the gap is big enough to be worth the trading costs (brokerage, taxes, etc). So small gaps can just… sit there, because it’s not profitable for anyone to bother closing them.
Think of arbitrage traders as the market’s auto-correct feature, they don’t fix typos instantly, but they clean it up quick enough that most people never notice.
Reason 4: Index-related buying/selling
The Nifty 50 is the benchmark index of NSE. The benchmark index of BSE is the Sensex (of 30 stocks). Large investors in mutual funds and ETFs would trade stocks specifically in line with Nifty/Sensex index rules. This results in buying/selling of shares in just one place (NSE or BSE) based on inclusion/exclusion of the stock in one of the indices which creates a temporary disruption in prices.
Conclusion
NSE and BSE maintain their own separate order books. This explains why small discrepancies in prices of stocks listed simultaneously on both exchanges are commonplace and considered normal. The discrepancy remains very small for actively traded stocks, as these discrepancies are quickly taken care of by arbitrageurs. However, the discrepancies widen for all illiquid stocks, the stocks affected by index rebalancing and any stocks coming for their first listing on the exchange. Retail investors need not worry themselves about such discrepancies, as brokers have sophisticated order-routing systems that ensure investors always get the best available price. In this respect, the difference in prices on the NSE and BSE is merely a minor example of how “market price,” simply means the location of agreement between buyers and sellers on the market at any given moment in time, simply depending on which exchange the participants happen to be trading on.
Bibliography
- Bajaj Finserv. Arbitrage Trading – Definition, Working and Limitations. bajajfinserv.in
- IIFL Capital. Arbitrage Opportunities in Stocks & Derivatives. indiainfoline.com
- Multibagg Market Pulse. NSE-BSE Price Gap and Arbitrage. multibagg.ai
- 021 Trade. Can an Arbitrage Trade Be Carried Out Between Two Exchanges? 021.trade
- Shabbir Bhimani. Understanding Arbitrage Trading With NSE and BSE. shabbir.in
- International Journal of Multidisciplinary Research Review. Arbitrage Trade Analysis of Stock Prices Traded in BSE and NSE. ijmrr.com
- Business Standard. Sebi’s Uniform Charge Rule Faces BSE Test Amid Concerns Over Fee Structure. business-standard.com
- National Stock Exchange of India. Official website — nseindia.com
- BSE Ltd. Official website — bseindia.com
- Securities and Exchange Board of India (SEBI). Official website — sebi.gov.in
