Encyclopedia5 min read
Time Decay in Options (Theta Effect)
How options lose value as expiry approaches — acceleration on weekly Nifty contracts.
Decay Curve
Time decay is non-linear — slow mid-week, violent last 2 days on weekly expiries. Buyers need move soon; sellers earn decay if price stays favorable.
Holding OTM lottery into expiry afternoon is donating premium.
Buyer vs Seller
Full theta greek reference inside.
Frequently Asked Questions
- Who is this guide for?
- Nifty and Bank Nifty option traders who want structured education around chain reading, OI, and risk — not signal tips.
- Can I trade from this article alone?
- Use it as education paired with live analysis on OptionTools. Paper trade or size down while validating ideas.
Key Takeaways
- Decay accelerates into expiry week.
- Buyers: shorter hold or ITM reduces bleed.
- Sellers: respect gap risk despite theta edge.
Related Articles
- Theta: Time Decay in OptionsTheta erodes option premium daily — the hidden cost of buying Nifty and Bank Nifty options, especially in expiry week.
- Expiry Day Strategies for Weekly Nifty & Bank Nifty OptionsPractical expiry-day tactics — pin risk, gamma scalping, when to stay flat, and how max pain and OI shape the final session.
- Option Buying Explained: Calls, Puts, and Defined RiskHow buying calls and puts works on Nifty and Bank Nifty — premium, breakeven, theta headwinds, and when buying beats selling.