Weekly Expiry

In one line: Weekly expiry options are short-dated index contracts that expire every week, offering cheap premiums and fast time decay — popular for short-term trading but demanding tight risk control because they move and decay quickly.

In simple words

Weekly options expire at the end of each week rather than each month. They are cheaper than monthly options and decay much faster, which makes them a favourite for short-term traders and expiry-day strategies on Nifty and Bank Nifty. The speed cuts both ways: big percentage gains are possible, but so are rapid losses from time decay and sharp moves.

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What weekly expiry means

A weekly expiry option settles at the end of its trading week, giving it just a few days of life. The NSE lists weekly expiries for its major index options; the exact expiry weekday and the list of products with weeklies are set by the exchange and revised periodically, so always check the current NSE calendar. Because they are so short-dated, weekly options carry little time value relative to monthlies and are dominated by Delta, Gamma and Theta rather than Vega.

Fast time decay is the defining feature

A weekly option spends its entire life in the steep part of the time-decay curve. Theta is high relative to the premium, so an out-of-the-money weekly can lose most of its value in two or three flat sessions. This is why weekly buyers need the move to happen quickly — being right eventually is worthless if the option decays first — and why premium sellers are drawn to weeklies to harvest that rapid decay.

High Gamma near expiry

As expiry approaches, at-the-money weekly options develop enormous Gamma, so their Delta swings sharply on small index moves. This makes the last day or two extremely volatile: positions can flip from profit to loss quickly, and naked sellers face accelerating risk. The combination of high Theta (favouring sellers) and high Gamma (favouring buyers on big moves) makes weekly expiry a battleground where risk control matters more than any prediction.

Who should trade weeklies

Weekly options suit traders with a clear short-term catalyst and strict risk discipline. They are efficient for expressing a quick directional view cheaply, and for premium-selling strategies that harvest decay. They are dangerous for buyers who hold and hope, and for sellers who over-size into the Gamma-heavy final sessions. Beginners are usually better served learning on monthlies before graduating to the faster weekly cycle.

Practical example (Nifty)

Weekly vs monthly expiry

Why it matters in practice

• Weekly options are cheap and decay fast — ideal for quick, catalyst-driven trades.
• High Theta favours sellers; high Gamma near expiry favours buyers on big moves.
• Buyers need the move to happen quickly; flat sessions destroy weekly premium.
• The Gamma-heavy final days demand small size and tight risk control.

Common mistakes

• Buying OTM weeklies and holding them flat while accelerating Theta wipes out the premium.
• Over-sizing short weekly options into the high-Gamma final sessions.
• Trading weeklies without a near-term catalyst, relying on hope over timing.
• Ignoring how a small index move can swing an ATM weekly's value near expiry.

What professionals do

Experienced traders use weeklies with precision: buyers enter with a clear catalyst and a tight time stop, taking profits quickly rather than riding decay; sellers harvest the rapid Theta but keep size small and step back from the most Gamma-heavy final hours unless they are expiry specialists. They treat the weekly as a fast, unforgiving instrument that rewards discipline and punishes hope.

Frequently Asked Questions

Sources & references

• NSE India — Expiry calendar

Educational content only — not investment advice.