SEBI Restores 30-Minute VWAP for F&O Expiry Settlement and Tweaks Closing Auction Timings From December 7

Following intense market feedback and heightened closing-hour volatility, the Securities and Exchange Board of India (SEBI) has overhauled its Closing Auction Session (CAS) framework and revamped the settlement methodology for futures and options (F&O) contracts.

Under the revised circular, the capital markets regulator will restore the 30-minute Volume-Weighted Average Price (VWAP) calculation for expiry-day settlements and recalibrate end-of-day market timings. Most of the operational revisions will take effect from December 7, 2026, while technical rules governing the transition of unexecuted iceberg and limit orders will follow on February 8, 2027.

What Triggered the Regulatory Intervention

SEBI initially introduced the Closing Auction Session mechanism on August 3, 2026, with the objective of enhancing price discovery at the equity cash close. Under that earlier framework, the settlement of expiring equity derivatives was directly linked to the equilibrium closing prices established during the cash auction session.

However, tying derivatives settlement to an auction window triggered extreme erratic swings, illiquidity complaints, and spikes in slippage on expiry afternoons. Brokerages reported lower retail order activity and significant settlement uncertainty. Following a consultation paper released on September 12, 2026, SEBI moved to delink derivatives settlement from auction prices and resolve trader bottlenecks.

Key Changes Effective December 7

The market regulator has finalized a structured timeline that separates normal trading, closing auctions, and derivative expirations.

Settlement Methodology for Expiring Derivatives:

• Index Derivatives: On expiry days, the settlement price will once again be calculated using the VWAP of the index's underlying constituent stocks during the final 30 minutes of continuous trading (3:00 PM to 3:30 PM).
• Stock Derivatives: Clearing corporations will determine the final settlement price based on the VWAP of the underlying security across all stock exchanges during the 3:00 PM to 3:30 PM continuous trading window.

New Timings and Operational Rules for the Closing Auction:

• Continuous trading in the equity cash market for F&O-eligible securities will now run until 3:30 PM instead of closing at 3:15 PM.
• The Closing Auction Session will operate as a dedicated 10-minute window from 3:30 PM to 3:40 PM on all trading days.
• Between 3:30 PM and 3:31 PM, exchanges will conduct the transition and calculate reference prices.
• Between 3:31 PM and 3:36 PM, market participants may enter both limit and market orders.
• After 3:36 PM, only limit orders will be accepted, and market orders can no longer be modified or cancelled.
• The auction order-entry window will feature a system-driven random closure between 3:38 PM and 3:40 PM, followed immediately by order matching.
• The post-closing session in the cash market will run from 3:50 PM to 4:00 PM.

Trading Cut-Offs for Derivatives:

• Expiring Index Contracts: On their designated expiry day, trading in expiring index contracts will cease strictly at 3:30 PM.
• Non-Expiring Index Contracts: Index contracts that do not expire on that day will continue trading until 3:45 PM.
• Stock Derivatives: Trading in individual stock options and futures will continue until 3:45 PM on all trading days, including their expiry days.

Impact on Retail Traders and Market Intermediaries

The return to the 30-minute continuous VWAP eliminates the sudden "cliff-edge" risk where auction price spikes could throw in-the-money or out-of-the-money options into chaos right at 3:30 PM. Because the benchmark spans trades across an entire half-hour block across exchanges, settlement prices become significantly harder to game and far easier to model.

Global brokerage Jefferies noted that reverting to the VWAP methodology addresses primary market grievances and removes lingering uncertainty, which should lower expiry-day volatility and support broker order flows that had dipped below pre-CAS levels.

Indian market participants, automated execution desks, and retail traders will need to adjust algorithmic setups and margin monitoring to align with the staggered trading cut-offs ahead of the December 7 rollout.