Their time value runs out by the close. Time value is the part of an option's price that pays for the time left. BANKNIFTY's monthly options expire at the close on the month's last Tuesday. If that is a holiday, they expire on the trading day before. An option in the money then pays the gap between the index and its strike. Every other option ends at zero. Take an at-the-money call, whose strike is closest to the index. If nothing moves, it keeps about 58% of its opening price at 13:30.
- Index
- NIFTY + BANKNIFTY
- Cycle
- NIFTY weekly · BANKNIFTY monthly
- Starts
- 09:15 IST
- Runs for
- 1 trading day · About 20 min at Normal speed
- Difficulty
- Intermediate
- Date
- 26 May 2026
- Expiry
- NIFTY 26 May 2026 · BANKNIFTY 26 May 2026
- IV
- NIFTY 13% · BANKNIFTY 14.43%
What is this market shaped like?
The market is a single BANKNIFTY monthly expiry day. Most versions start at the open. The From 13:30 version joins for the last part of the day. In this market an expiry day counts as a little more than a normal day, with a busier last hour. The Both indices expire version adds NIFTY. Its monthly options expire the same day.
What is left of an at-the-money call's price, if nothing moves
| When | Left of the day's opening price |
|---|---|
| Open | 100% |
| 12:00 | 70% |
| 13:30 | 58% |
| 14:30 | 48% |
| 15:00 | 39% |
Nothing moves means the index stays still and IV stays the same. IV (implied volatility) is the size of move option prices expect.
At the close, time value is gone. Only the in-the-money gap is left.
What will you see?
- Delta is how much an option moves for each point the index moves. Gamma is how fast delta changes. Near the money on expiry day, gamma is large, so small moves swing prices a lot.
- In the Choppy version the index keeps coming back to one level. Watch who that helps: option buyers or option sellers.
- The last hour moves more than a normal last hour. Watch what that does to the options near the money.
Which version do you want?
Each version is the same kind of market with 1 thing changed. Choose one to start it.
- Whole day · Choppy
- From 13:30
- Both indices expire
What should you try?
Try this with 1 lot of a call and 1 of a put. A lot is the smallest size you can trade.
- At 13:30, buy 1 lot of the at-the-money call and 1 of the at-the-money put.
- Write down both prices every 30 minutes.
- Let them run to the close. See what each one pays.
What should you check afterwards?
- How far did BANKNIFTY move after 13:30?
- Did the call and the put together end above or below what you paid?
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