Explain the significance of settlement price methodology in derivatives markets and the risks associated with expiry-day volatility.

The settlement price is the reference price at which futures and options contracts are finally squared off on expiry. Because payoffs of crores worth of contracts hinge on a single number, its computation method is a core pillar of market integrity.

Significance of settlement price methodology

• Determines final payoffs: In cash-settled index derivatives, profit or loss depends wholly on the closing reference price, so the averaging window chosen decides who gains and who loses.
• Manipulation resistance: A Volume-Weighted Average Price (VWAP) over a window, rather than a last-traded price, makes it costly to distort the close. SEBI's new Closing Auction Session (CAS), introduced in the equity cash segment in January 2026, was designed precisely to strengthen closing-price discovery [2].
• Hedging and index-tracking accuracy: Passive funds and hedgers rebalance at the close; an unreliable settlement price raises tracking error and hedging cost.
• Design must match market structure: SEBI now proposes a blended VWAP combining the last 30 minutes of continuous trading with the 10-minute CAS window, or a temporary reversion to the pre-CAS method [1][3].

Risks associated with expiry-day volatility

• Concentrated speculative activity: SEBI observed "hyperactivity" in expiring index options and in Indicative Equilibrium Price (IEP)-based trading during CAS, prompting the review [1][3].
• Price distortion and gaming: Thin, time-compressed windows allow small order flows to move settlement values; hence the proposal to stop displaying the indicative index value during CAS [1].
• Retail investor losses: SEBI's index-derivatives framework review flagged investor-protection and market-stability concerns from heavy expiry-day options turnover [4].
• Systemic and operational stress: Expiry-day surges strain margining and clearing, which is why expiry days were standardised in 2025 [5].

Thus, settlement price methodology is not a technicality but the anchor of fair derivative settlement. SEBI's consultative course-correction within months of CAS go-live — with comments open till October 2026 — shows adaptive, transparent regulation that balances efficient price discovery with investor protection.