Weekly versus monthly expiry

Weekly and monthly expiry are the two tenors in which Indian exchange-traded options trade, distinguished by how often a contract expires and, since the 2024 to 2025 reforms, by how few instruments carry a weekly. After the Securities and Exchange Board of India restricted weekly options to one index per exchange in November 2024, only the Nifty 50 on the National Stock Exchange and the Sensex on the Bombay Stock Exchange have a weekly contract, while every single-stock option trades in a monthly tenor only.

The difference is not cosmetic. A weekly option lives about five trading sessions and a monthly about twenty, which changes the speed of time decay, the concentration of gamma risk, the liquidity profile, and the strategy that fits each. This article sets out which instruments carry each tenor, how the two expire on Zerodha , and the decay and liquidity differences that decide which one a given strategy should use.

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Which instruments carry each tenor

The tenor map changed sharply between October 2024 and September 2025. Before then, five index weeklies traded across the week. Now the split is simple.

A weekly option exists on two indices only. The Nifty 50 weekly expires every Tuesday on the NSE and the Sensex weekly expires every Thursday on the BSE, the survivors of the weekly expiry contraction of November 2024 . No other index, and no single stock, carries a weekly contract. Bank Nifty , Nifty Financial Services, Nifty Midcap Select, Nifty Next 50 and Bankex lost their weeklies in that contraction and trade monthly only; the Bank Nifty detail sits in the phaseout of Bank Nifty weekly options .

A monthly option exists on every index that trades options and on every single stock in the F&O list. Index monthlies and stock monthlies expire on the last Tuesday of the month on the NSE and the last Thursday on the BSE, the weekday set by the SEBI circular of 26 May 2025 and effective 1 September 2025. Single-stock options have only ever traded monthly in India; there is no historical weekly stock option to reinstate.

Sources: SEBI Measures to Strengthen the Index Derivatives Framework, 1 October 2024; SEBI expiry-day circular, 26 May 2025; NSE and BSE contract specifications, accessed June 2026.

How each expires on Zerodha

On Kite the two tenors appear as separate expiry dates above the options chain . A weekly Nifty contract shows the Tuesday of its week; a monthly shows the last Tuesday of its month. In the final week of the month the two coincide, since the last weekly Nifty and the monthly Nifty both expire on the same last Tuesday, and that session carries the combined open interest of both tenors. The same coincidence happens on the BSE on the last Thursday for Sensex.

Settlement differs by underlying, not by tenor. Index options, weekly or monthly, are cash-settled: an in-the-money index option is settled in cash against the index closing value, with no delivery. Single-stock options, which are monthly only, are physically settled : an in-the-money stock option held to expiry obliges the holder to take or give delivery of the underlying shares at the strike. That is why a forgotten weekly index option costs you a cash settlement while a forgotten monthly stock option can trigger a large delivery obligation; the consequences are set out in what happens to unsquared options at expiry .

Theta decay across the two tenors

Theta, the daily loss of an option’s time value, is the central difference between the tenors. An option’s premium is intrinsic value plus time value, and time value drains to zero by expiry. The question is over how many sessions.

A weekly option carries its full time value across roughly five trading sessions. The same time value in a monthly option is spread across about twenty. So a weekly option’s theta, expressed as a fraction of its premium, is larger early in its life than a monthly’s, and the decay accelerates as expiry nears. The acceleration is not linear: time value falls roughly with the square root of time remaining, so the final two or three sessions of any option strip the most value, and a weekly reaches that steep zone within days of listing. The theta decay profile is the reason short-dated option selling looks attractive on paper and the reason short-dated option buying loses so reliably.

For the seller, the weekly’s fast decay is the appeal: premium collected decays quickly, and a position opened and closed within a week recycles capital faster. For the buyer, the same decay is the enemy: a weekly option bought on a Friday loses two days of time value over the non-trading weekend before Monday’s session, and a directional view that takes a week to play out can expire worthless even if the eventual move was correct. The monthly tenor gives a thesis more time, at the cost of slower premium collection for the seller. The trade-off is described under expiry-day options trading , where the steep terminal decay of any tenor concentrates on the final session.

Gamma and the concentration of risk

Theta does not travel alone. The same approach to expiry that accelerates decay also raises gamma, the rate at which an option’s delta changes as the underlying moves. A near-expiry at-the-money option has high gamma, so its delta can swing from near zero to near one over a small move in the underlying. For an option seller, high gamma near expiry means a position that looked delta-neutral in the morning can carry a large directional exposure by the afternoon.

A weekly option reaches that high-gamma zone every week; a monthly only in its final week. So a systematic weekly seller faces sharp gamma risk roughly four times as often as a monthly seller. The premium a weekly seller collects compensates for taking that risk repeatedly. When an expiry-day move on the Nifty or Sensex runs more than about 2 per cent, the loss on short weekly positions can wipe out several weeks of collected premium in a single session, which is the structural reason the SEBI September 2024 study found weekly options the dominant retail loss vector. Sellers should size positions against that tail, not against the average week.

Liquidity differences

Liquidity follows the surviving weeklies. For index options the weekly Nifty 50 and Sensex contracts carry the bulk of turnover and show the tightest bid-ask spreads, particularly in the at-the-money strikes in the final two sessions. The monthly index contract is liquid but thinner than the near weekly until the last week, when monthly volume builds.

Single-stock options sit in a different world. With no weekly tenor, the monthly stock option is the only contract, and its liquidity varies widely by underlying. Large-cap names with heavy F&O interest show usable spreads in the near month; smaller names in the F&O list can have wide spreads and sparse open interest, especially in far strikes and the far month. A trader moving from index weeklies to stock options should check the open interest and spread on the specific strike before assuming a fill, and should weigh the physical settlement obligation that comes with holding any stock option to expiry.

Choosing a tenor for a strategy

The tenor is a strategy decision, not a preference. A few patterns hold.

Short-horizon premium selling, where the view is that the underlying stays range-bound for a few days, fits the weekly tenor: fast theta, fast capital recycling, accept the repeated gamma risk and size small. A view that needs weeks to develop fits the monthly: slower decay gives the thesis time, and the single late-month gamma spike is easier to manage than four weekly spikes. Hedging a cash or futures position usually uses the monthly, matching the hedge horizon to the position rather than rolling a weekly four times and paying four sets of transaction costs .

Two cost factors weigh against over-using weeklies. Each weekly cycle incurs its own brokerage, securities transaction tax and exchange charges, so rolling a weekly four times a month costs more in fixed charges than holding one monthly. And the STT on an exercised in-the-money option and the physical-settlement charge on stock options make holding any option to expiry more expensive than squaring off before it, a cost that recurs weekly if you trade the weekly tenor to expiry. For most retail strategies the tenor choice should start from the strategy horizon and the cost of recurring rolls, not from the appeal of fast weekly decay.

See also

• How the F&O expiry calendar works
• Weekly expiry contraction (November 2024)
• Nifty weekly expiry on Zerodha
• Sensex weekly expiry on Zerodha
• The phaseout of Bank Nifty weekly options
• Theta decay
• Expiry day options trading
• What happens to unsquared options at expiry
• Physical settlement of stock F&O
• STT on options exercise
• Option premium
• Implied volatility
• Gamma of an option
• Delta of an option
• Open interest
• Nifty 50 index
• Sensex index
• Bank Nifty index
• National Stock Exchange
• Bombay Stock Exchange
• Securities and Exchange Board of India
• Zerodha
• Kite by Zerodha
• How to use the options chain on Kite
• Zerodha F&O charges
• STT hike on F&O (October 2024)

External references

• 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
• NSE: Equity derivatives contract specifications
• Zerodha Varsity: Options theory for professional trading
• Zerodha support: F&O trading FAQs

References

1. Securities and Exchange Board of India, “Measures to Strengthen the Index Derivatives Framework,” circular dated 1 October 2024, sebi.gov.in, accessed June 2026.
2. Securities and Exchange Board of India, “Final Settlement Day (Expiry Day) for Equity Derivative Contracts,” circular dated 26 May 2025, sebi.gov.in.
3. 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.
4. National Stock Exchange of India, equity derivatives contract specifications, nseindia.com, accessed June 2026.
5. BSE Limited, derivatives segment contract specifications, bseindia.com, accessed June 2026.