Summary:
SEBI has proposed a new framework to align stock price bands and reference prices across NSE and BSE. The move aims to reduce pricing discrepancies in illiquid and small-cap stocks, improve market efficiency, and enhance investor protection. If implemented, the proposal could create a more transparent trading environment for retail investors.
The Securities and Exchange Board of India (SEBI) has proposed a significant market structure reform aimed at eliminating price discrepancies between stocks traded on the National Stock Exchange (NSE) and the Bombay Stock Exchange (BSE). While the proposal may appear technical, its impact could be substantial, particularly for retail investors active in small-cap and illiquid stocks.
Under the proposal, if a stock remains untraded on one exchange during a session but trades actively on the other, the inactive exchange will adopt the active exchange’s closing price as the reference point for the next day’s pre-open session and price band calculations. This would ensure that both exchanges begin the trading day with a common baseline.
Why the Issue Exists
India’s market structure is unique, with NSE and BSE maintaining separate order books for thousands of overlapping stocks. While price differences in large-cap stocks are usually corrected within seconds through arbitrage, the same is not true for illiquid small-cap and SME stocks.
More than 5,000 stocks are listed on BSE, with over 3,200 also listed on NSE. A significant portion of these stocks trade with low volumes, often resulting in one exchange reflecting stale prices while the other continues active price discovery.
According to SEBI’s estimates, several hundred small-cap and micro-cap stocks show price differences of more than 2% between NSE and BSE on any active trading day. In extreme cases, the gap can reach 5%. For a ₹200 stock, that translates into a ₹10 difference between exchanges.
Impact on Retail Investors
These pricing gaps can directly affect retail investors. For example, if a stock closes at ₹100 on NSE but remains largely inactive on BSE, the latter may continue using an outdated reference price of ₹98 from previous sessions. Investors trading on BSE could unknowingly execute orders at prices disconnected from the broader market consensus.
Such inefficiencies create opportunities for high-frequency traders and arbitrage desks to exploit price differences across exchanges. While the practice is legal, it often results in value shifting away from retail participants.
What Changes Under SEBI’s Proposal?
The reform does not merge NSE and BSE order books or interfere with live trading. Instead, it synchronises the reference price used for pre-open sessions and circuit limits. SEBI has also sought feedback on whether the rule should apply only to stocks with zero trades or be extended to stocks with extremely low trading activity.
Broader Benefits for the Market
The proposal is expected to improve execution quality for retail investors, reduce tracking errors for small-cap ETFs, enhance price discovery, and create a more efficient trading environment. It could also improve confidence among domestic and foreign institutional investors in India’s smaller companies.
The move follows a series of market reforms by SEBI, including T+1 settlement, SME IPO regulations, and derivatives market changes. As India’s demat account base has grown from 4 crore in 2020 to over 17 crore today, improving market infrastructure has become increasingly important.
Bottom Line
SEBI’s price band harmonisation proposal may not grab headlines, but it addresses a long-standing structural inefficiency. By aligning reference prices across NSE and BSE, the regulator aims to eliminate avoidable price distortions, improve fairness, and strengthen investor confidence, especially in the small-cap segment where such discrepancies are most common.
