The Securities and Exchange Board of India (SEBI) is set to overhaul the settlement process for derivatives after the Closing Auction Session (CAS) led to a significant drop in trading volumes and increased volatility.
- SEBI is reviewing the settlement price determination for derivative contracts due to industry pushback.
- A 10-minute mismatch between the Closing Auction Session (CAS) end time and derivatives trading end time is causing extreme uncertainty.
- Institutional investors, who drive 60-65% of turnover, are avoiding the market to mitigate hedging risks.
- NSE derivatives turnover hit its lowest level since November 2023 in August.
The Securities and Exchange Board of India (SEBI) has announced a potential shift in the methodology used to determine settlement prices for derivative contracts. This move comes as a direct response to the instability triggered by the implementation of the Closing Auction Session (CAS), which has left institutional traders struggling with price visibility and risk management.
The core of the problem lies in a critical timing mismatch. Currently, the CAS concludes at 3:30 PM, while trading in the derivatives segment continues for an additional 10 minutes. For institutional players—including mutual funds, foreign portfolio investors (FPIs), and algorithmic traders—this gap creates a dangerous window where they cannot effectively hedge their positions in the cash market against their bets in the derivatives market.
Why This Matters
BozokMedia analysis shows that the current structure breaks the fundamental symmetry required for arbitrage and hedging. When the cash market (CAS) closes first, traders are left exposed to price swings in the derivatives market without the ability to adjust their underlying holdings. This has led to a 'liquidity freeze' where big players simply exit both segments to avoid catastrophic losses, especially on expiry days for the Nifty 50 and Sensex.
The mismatch in session timings has transformed a tool for price discovery into a source of systemic volatility for institutional hedgers.
The impact is clearly visible in the data. The National Stock Exchange (NSE) reported that total derivatives turnover for August was ₹34.48 lakh crore, the lowest since late 2023. Market experts, including Shweta Rajani of Anand Rathi Wealth, note that the decline in average daily options turnover by 20% is a systemic reaction to the CAS introduction rather than a random market dip.
To resolve this, the industry is lobbying for two primary changes: aligning the closing times of both the CAS and derivatives sessions, and de-linking derivative settlement prices from CAS prices on expiry days. Many suggest returning to the Volume-Weighted Average Price (VWAP) method to ensure fairer price discovery.
| Feature | Pre-CAS Era | Current CAS System |
|---|---|---|
| Closing Time | Aligned (Cash & Derivatives) | 10-Minute Gap |
| Settlement Basis | VWAP (Volume Weighted) | CAS Closing Price |
| Volatility | Lower/Predictable | High (due to thin volumes) |
Frequently Asked Questions
Q1: Why are institutional investors avoiding the CAS?
They lack the ability to hedge their positions in real-time due to the 10-minute gap between the cash market closing and the derivatives market closing.
Q2: What is the proposed solution for expiry days?
Experts suggest using the traditional Volume-Weighted Average Price (VWAP) instead of the CAS price to reduce extreme volatility.
