The Indian expiry cycle

The one rule to remember

Effective 01 September 2025, NSE and BSE consolidated their expiry days:

The full Indian expiry calendar (post 01-Sep-2025)

Only two products carry weekly options now: Sensex (BSE Thursday) and Nifty (NSE Tuesday). All other weeklies were discontinued in SEBI’s 2024 F&O consolidation.

What changed on 01 September 2025

Before the switch:

• Nifty weekly expired Thursday
• Sensex weekly expired Tuesday

After the switch:

• Nifty weekly moved to Tuesday
• Sensex weekly moved to Thursday
• They swapped days. Every NSE product also went from last Thursday of month to last Tuesday.

For traders, this means:

• Any book, article, or reference dated before Sep 2025 shows OLD expiry days — always verify
• Your muscle memory around expiry-day routines needed to shift
• Sensex is now the “Thursday product”; Nifty is now the “Tuesday product”

Picking the right expiry for your strategy

For selling premium (short strangles, iron condors)

Weekly cycle — enter early, exit 1-2 days before expiry:

• Sensex weekly: enter Friday afternoon (day after Thursday expiry clears), exit following Wednesday
• Nifty weekly: enter Wednesday afternoon (day after Tuesday expiry clears), exit following Monday

Avoid entering less than 2 days from expiry (gamma risk) or holding into the last hour (pin risk).

For buying volatility (long straddles, backspreads)

Weekly’s too short for most vol expansion plays. Use monthly options:

• Sensex monthly (last Thursday) gives 30+ days for a move to develop
• Nifty monthly (last Tuesday) similar

For directional bets

Match your holding period to the expiry:

• 2-5 day view → weekly (Sensex or Nifty)
• 2-4 week view → monthly
• Longer view → next-month monthly (Indian LEAPS-like options are thin)

For calendar / diagonal spreads

• Sell weekly, buy monthly — the classic PMCC-style setup
• Keep both legs on the same exchange for cleaner Greeks and margin

The multi-index arb angle

Because Sensex and Nifty now expire on different days, you have:

• Different theta profiles on any given day of the week
• Potentially arbitrageable IV differences on similarly-correlated indices
• More opportunity for cross-index calendar structures

Institutional traders exploit this. Retail can too, if you understand both indices’ behavior.

Event calendar

Certain macro events land on specific weekdays. Know these to avoid selling premium into headwinds:

Rule for premium sellers: avoid entering short-vol trades if any 🔥🔥+ event falls within your expiry window. High premium often signals real risk, not opportunity.

Sensex-specific practical notes

Since Sensex is now the top-volume Indian option:

1. Liquidity concentration — most flow is on the current-week Thursday expiry. Off-cycle expiries (monthly beyond current week) have wider spreads.

2. Cross-exchange consideration — Sensex is on BSE, Nifty on NSE. If you trade both, you’re on both exchanges with separate margin pools and separate contract notes.

3. Strike density — Sensex option chain typically has strikes at every 100 points near ATM. Nifty typically at every 50 points.

Bankex — BSE’s banking exposure

Bankex is BSE’s banking index (BSE counterpart to Bank Nifty). Monthly-only after SEBI’s 2024 rationalization.

If you want banking-sector options exposure:

• Bank Nifty monthly (NSE, last Tuesday) — more liquid, broader participation
• Bankex monthly (BSE, last Thursday) — different day, decent liquidity

The weekly trading calendar (post 01-Sep-2025)

• Monday: quiet day; second day of new Nifty weekly cycle; second-to-last of Sensex weekly
• Tuesday: Nifty weekly expiry (NSE). Last Tuesday of month = Nifty monthly + all NSE stock/index monthlies
• Wednesday: Start of new Nifty weekly cycle
• Thursday: Sensex weekly expiry (BSE). Last Thursday of month = Sensex monthly + Bankex/Sensex 50 monthly
• Friday: New Sensex weekly cycle starts; RBI decisions often fall here
• Weekend: global news accumulates; Monday gap possible

Structure entries and exits around this rhythm.

Which weekly should YOU trade?

Key takeaways

1. NSE → Tuesday. BSE → Thursday. One sentence, everything else follows.
2. Only Sensex (Thursday) and Nifty (Tuesday) have weekly options. Every other product is monthly-only after the 2024 consolidation.
3. All NSE monthly expiries fall on the last Tuesday — Nifty, Bank Nifty, Finnifty, Midcap Nifty, Nifty Next 50, and all single stocks (Reliance, TCS, HDFC, etc.).
4. All BSE monthly expiries fall on the last Thursday — Sensex, Bankex, Sensex 50.
5. Physical delivery on stock options — last Tuesday of month. Close before if you don’t want shares.
6. Pre-September 2025 references show OLD expiry days. Always verify.