Bankex Put Option Surges 14,700 Percent Amid Sharp Expiry Day Decline
A Bankex put option experienced a massive intraday spike during Thursday's closing auction, highlighting the severe risks options sellers face during sudden expiry-day volatility.
A Bankex 65,000 put option expiring on Thursday surged from ₹6.65 to ₹987 within minutes, representing a gain of nearly 14,700 percent. This extraordinary price movement occurred as indicative closing levels during the market auction briefly signaled a decline of almost 3 percent in the Sensex.
Just before the closing auction session commenced, the broader index had been down by a modest 0.3 to 0.4 percent. The sudden steepening of the projected decline triggered a rapid cascade of buying in out-of-the-money put contracts.
Several other Bankex put options clustered around the 65,000 strike price experienced similar premium spikes, ranging from 500 to 4,500 percent. Market participants on social media reported that numerous options sellers incurred heavy losses as a result of this unexpected expiry-day volatility.
At the final close, the Sensex settled at 76,933.59, reflecting a drop of 539.35 points, or 0.70 percent. The Bankex index fared worse, ending the session at 64,313.15 after shedding 1,094.16 points, or 1.67 percent.
The downturn was notably more contained on the National Stock Exchange, highlighting a divergence in market behavior. The Nifty closed down 116.90 points, or 0.48 percent, at 24,090.85.
Similarly, the Bank Nifty index recorded a modest decline of 273.80 points, or 0.47 percent, finishing at 57,509.95. This contrast between the BSE and NSE banking indices underscores the localized nature of the auction-period pressure.
For institutional investors and derivatives traders, this episode serves as a stark reminder of the pricing risks inherent in expiry-day trading. Sudden shifts in indicative closing prices can rapidly transform seemingly safe short option positions into substantial financial liabilities.
Market professionals will likely scrutinize the auction mechanics that allowed such a dramatic, albeit brief, price dislocation. Managing directional exposure during these final trading minutes remains a critical operational challenge for volatility sellers in the Indian derivatives market.
