--- title: "Term structure: why do weekly and monthly IVs differ?" description: "Weekly and monthly expiries cover different numbers of days, so their implied volatilities differ when the market prices an event inside one expiry." source_url: "https://www.rupeecase.com/learn/questions/weekly-vs-monthly-iv" --- On 1 Feb 2026 the nearest weekly expiry priced far more volatility than the monthly, at the close of the Budget session At the money implied volatility of each Nifty expiry on 1 Feb 2026 against days left, from the NSE end of day chains. Weekly and monthly expiries are shown on one line; the nearest weekly expired on 3 Feb. Source: NSE end of day data, computed by RupeeCase. As of 1 Feb 2026. A weekly and a monthly option differ in one way that matters here. A weekly covers fewer days, so an event on a single day inside it has a larger effect on its average volatility. The term structure plots the at the money implied volatility of each expiry against the days left. A kink in the curve is a sign that the market prices something specific inside one window, or has just reacted to it. The chart is the Budget week. The Budget was presented on Sunday 1 Feb 2026, a special NSE session, and the index fell that day. These prices are the close of that session, after the news. The nearest weekly, expiring on 3 Feb, sat at the top of the curve, far above the monthly expiring on 24 Feb: a few days left meant a sharp move weighed heavily on its average. One session later, on 2 Feb, the same expiries sat lower on the curve. The second reason is the chain itself. Volume and open interest concentrate in different strikes for each expiry, so the at the money reading of a thin weekly can be noisier than a monthly. The chain shows the traded strikes beside the figure, and a figure resting on few traded strikes deserves less weight. Compare like with like. Use the same day, the same underlying and the same method for both expiries. On 10 Jun 2026 the weekly and monthly expiries sat close together, so the term structure was close to flat that day. A flat curve and a spiked curve are both readings of prices, not views on direction. **Before you trade.** Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. [Read the SEBI study](https://www.sebi.gov.in/reports-and-statistics/research/aug-2026/study-profitability-of-individual-traders-in-the-equity-derivatives-segment-fy25-fy26-_103835.html) Term structure: why do weekly and monthly IVs differ?Weekly and monthly expiries cover different numbers of days, so their implied volatilities differ when the market prices an event inside one expiry and not the other, and the term structure shows that gap across all the expiries on one date. On the close of 1 Feb 2026, the Budget session, the nearest weekly carried far more volatility than the monthly. LGo deeper ## Where Learn teaches this. [Go deeperTerm structure and event variance10 min, Advanced](/learn/path-16/module-16-9-term-structure-and-event-variance)[Go deeperExpiry day: gamma, theta, settlement and the rules10 min, Intermediate](/learn/path-17/module-17-12-expiry-day) SSources ## Go to the source. 3 sources, NSE the most cited The publisher of each source listed below. Source: Module undefined source list. 1. [NSE, equity derivatives contract specifications: lots, expiries and settlement](https://www.nseindia.com/static/products-services/equity-derivatives-contract-specifications) NSE 2. [NSE, option chain (strike level quotes and open interest)](https://www.nseindia.com/option-chain) NSE 3. [NISM, Series VIII equity derivatives certification test objectives](https://www.nism.ac.in/revamp-nism/test-objectives-revised-nism-series-viii-equity-derivatives-certification-examination/) NISM ?Questions people ask ## Related questions. 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