Sensex weekly expiry on Zerodha
Sensex weekly options are the Bombay Stock Exchange surviving weekly index benchmark, the single weekly index contract the BSE is permitted to run under the Securities and Exchange Board of India one-weekly-per-exchange rule of November 2024. They are options on the Sensex , the BSE 30-stock benchmark, expiring every Thursday since 1 September 2025, cash-settled, and listed on Zerodha in the BSE F&O segment on Kite .
When SEBI restricted each exchange to one weekly index expiry, the BSE chose the Sensex over its Bankex contract, mirroring the NSE’s choice of Nifty 50 over Bank Nifty. The Sensex weekly then moved from its old Friday slot to Thursday in the September 2025 weekday standardisation. This article sets out the expiry day, the lot size and how it was raised, the cash settlement, and how Zerodha lists and charges the contract.
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Expiry day and the move from Friday to Thursday
The Sensex weekly expires every Thursday. That is recent. Until the September 2025 reform the Sensex weekly expired on Friday, the last weekday in the old five-expiry calendar. The SEBI circular dated 26 May 2025 required each exchange to fix a single expiry weekday, Tuesday or Thursday, and the BSE chose Thursday for every derivative it lists. The change took effect on 1 September 2025, with contracts opened before 29 August 2025 running out on the old Friday schedule and every new contract expiring Thursday.
The rule is uniform across BSE derivatives: weekly Sensex on Thursday, monthly Sensex on the last Thursday of the month, and monthly Bankex and stock-equivalent contracts also on the last Thursday. A fresh weekly contract is listed as the near one expires, so several consecutive Thursday expiries trade at once. If a scheduled Thursday is a trading holiday, the contract expires on the previous trading day, and the BSE publishes the holiday-adjusted expiry dates by circular at the start of each year. The general structure sits in how the F&O expiry calendar works .
Lot size and the Rs 15 lakh notional floor
The Sensex options lot size is 20. It was 10 until November 2024, when SEBI raised the minimum contract notional from about Rs 5 lakh to a band of roughly Rs 15 lakh to Rs 20 lakh as one of the October 2024 derivatives framework measures. The BSE doubled the Sensex lot from 10 to 20 so the contract value would clear the Rs 15 lakh floor.
The arithmetic is direct: contract notional equals the Sensex level times the lot size. With the index near 80,000, a lot of 20 puts the notional around Rs 16 lakh, inside the prescribed band. Because the band is enforced on the index level, the lot is reviewed periodically and recalibrated as the Sensex moves; the exchanges revised several index lot sizes again in late 2025 as index levels rose. Always read the current lot from the Kite contract rather than assuming a fixed number, because the margin you post scales directly with it. For the margin computation see SPAN margin on Zerodha .
| Parameter | Sensex weekly option |
|---|---|
| Underlying | BSE Sensex, 30-stock benchmark |
| Exchange | Bombay Stock Exchange (BSE) |
| Weekly expiry | Every Thursday since 1 September 2025 |
| Monthly expiry | Last Thursday of the month |
| Lot size | 20 (raised from 10 in November 2024) |
| Settlement | Cash, against Sensex closing value |
| Kite segment | BSE F&O (BFO) |
Sources: SEBI Measures to Strengthen the Index Derivatives Framework, 1 October 2024; SEBI expiry-day circular, 26 May 2025; BSE derivatives contract specifications, accessed June 2026.
Cash settlement
A Sensex option is cash-settled. On expiry, an in-the-money option is settled in cash against the Sensex closing value: the holder receives the intrinsic value, the writer pays it, and no shares change hands because the underlying is an index, not a deliverable security. An out-of-the-money option lapses worthless. This is the same mechanism as the Nifty weekly and unlike a single-stock option, which goes to physical settlement .
The practical consequence is that a forgotten in-the-money Sensex option costs you only the cash settlement and its charges, not a delivery obligation. The charges still matter: a securities transaction tax applies on the option, and exchange and other statutory charges accrue. For most strategies it is still cheaper to square off before expiry than to let an in-the-money index option go to settlement, because the settlement-day STT on an exercised option is computed differently from the STT on a normal sale. The detail is in STT on options exercise and the broader picture in what happens to unsquared options at expiry .
How Zerodha lists Sensex options
Sensex options trade in the BSE F&O segment, shown as BFO on Kite . To trade them you need the F&O segment activated on your account; the process is in how to activate F&O on Zerodha . Search the Sensex derivative in the Kite marketwatch, open the options chain , and the available Thursday expiries appear as selectable dates above the strikes. The chain shows the lot size and the expiry date directly, so you can confirm both before placing an order.
Two listing points catch BSE-side traders. First, Sensex strikes are spaced at intervals set by the BSE, wider in absolute terms than Nifty strikes because the index level is higher, so the at-the-money strike steps in larger rupee increments. Second, the BSE expiry falls on Thursday while an NSE position expires Tuesday, so a strategy that hedges a Sensex position with a Nifty leg has the two legs expiring two days apart, which matters for any calendar or cross-index spread .
Charges, margin and risk
Selling a Sensex option requires posting SPAN plus exposure margin plus the additional extreme loss margin , including the 2 per cent expiry-day add-on introduced in the October 2024 framework. Buying an option requires only the premium, but the premium can decay to zero by Thursday. The charges on a Sensex option trade, brokerage, STT, exchange transaction charges, GST, SEBI and stamp charges, are set out in Zerodha F&O charges ; the STT on options sale rose to 0.1 per cent of premium on the sell side from 1 October 2024 under the STT hike , and to 0.15 per cent from 1 April 2026.
The risk warning that governs all index-option writing applies here. SEBI’s September 2024 study found that more than 90 per cent of individual F&O traders lost money over FY22 to FY24, with weekly options the dominant loss vector, a finding detailed in the SEBI study on retail F&O losses . A short Sensex option carries theoretically unlimited loss on the call side and large loss on the put side, concentrated into the high-gamma final session every Thursday. Size positions against an adverse expiry-day move of more than 2 per cent, not against an average week.
See also
- How the F&O expiry calendar works
- Weekly versus monthly expiry
- Nifty weekly expiry on Zerodha
- The phaseout of Bank Nifty weekly options
- Weekly expiry contraction (November 2024)
- Sensex index
- Bombay Stock Exchange
- Nifty 50 index
- Bank Nifty index
- Securities and Exchange Board of India
- Expiry day options trading
- What happens to unsquared options at expiry
- Physical settlement of stock F&O
- STT on options exercise
- Theta decay
- Gamma of an option
- SPAN margin on Zerodha
- Extreme Loss Margin (ELM)
- Zerodha F&O charges
- STT hike on F&O (October 2024)
- SEBI F&O entry barrier rules 2024
- SEBI 90 per cent retail F&O loss study
- Zerodha
- Kite by Zerodha
- How to use the options chain on Kite
- How to activate F&O on Zerodha
External references
- BSE: Derivatives segment contract specifications
- SEBI: Final Settlement Day (Expiry Day) for Equity Derivatives, circular dated 26 May 2025
- SEBI: Measures to Strengthen the Index Derivatives Framework, 1 October 2024
- Zerodha support: F&O trading FAQs
- Zerodha Varsity: Options theory for professional trading
References
- Securities and Exchange Board of India, “Final Settlement Day (Expiry Day) for Equity Derivative Contracts,” circular dated 26 May 2025, sebi.gov.in, accessed June 2026.
- Securities and Exchange Board of India, “Measures to Strengthen the Index Derivatives Framework,” circular dated 1 October 2024, sebi.gov.in.
- BSE Limited, derivatives segment contract specifications and lot-size circulars, bseindia.com, accessed June 2026.
- Securities and Exchange Board of India, “Study on Profile and Performance of Individual Traders in Equity Futures and Options (F&O) Segment,” September 2024, sebi.gov.in.