Definition
Expiry Day Trading
Expiry day trading is short-term option trading on the day a contract expires, dominated by rapid theta burn and high gamma.
On expiry day, options have hours to live, so out-of-the-money premiums collapse through theta burn while at-the-money options carry extreme gamma — small index moves cause outsized premium swings. Sellers try to capture the fast decay; buyers chase explosive, low-cost moves.
Indian Nifty and Bank Nifty expiry days see massive volume and very thin, cheap options, making it the busiest and riskiest session of the week. Strategies range from selling far OTM strikes for the burn to lottery-style buying, but the gamma and pin risk make tight stops and discipline essential.
Related terms
- GammaGamma measures how fast an option's delta changes as the underlying moves — the rate of change of delta.
- Max PainMax pain is the strike price at which the largest number of option buyers would lose money on expiry.
- Theta Burn (Expiry Day)Theta burn is the extreme, rapid loss of option time value on expiry day, when remaining premium collapses toward zero.
Plain-English explainer from The Dispatch Investors Encyclopedia. General information, not financial advice.