Volatility Term Structure Trading
Volatility term structure trading involved exploiting differences in implied volatility levels between near-month and far-month options on the same underlying, with traders using calendar spreads or other multi-expiry strategies to profit from convergence or divergence in these IV differentials across the Nifty expiry curve.
The term structure of implied volatility described how IV varied across different expiry months for options on the same underlying. Under normal market conditions, near-month options on Nifty and Bank Nifty carried higher implied volatility than far-month options because near-term uncertainty was compressed into fewer days, making each day's gamma exposure more intense. Far-month options spread this uncertainty across more time, resulting in a lower annualised IV reading.
This normal 'contango' shape of the IV term structure — near-month IV higher than far-month IV — was regularly observed in Indian F&O between major events. It made calendar spreads structurally interesting: selling the near-month option at higher IV and buying the far-month option at lower IV appeared attractive on paper. The trade profited if near-month IV declined relative to far-month IV, or if the underlying moved minimally and near-month theta decay outpaced far-month decay.
During stress events or when a scheduled event fell within the near-month expiry window, the term structure could invert — near-month IV dropped below far-month IV in relative terms as the event approached and resolved, or the market priced a large far-month event (such as an election falling in the far-month period) at a premium. These inversions created reverse calendar opportunities, where traders sold the far month and bought the near month.
Practical trading of the term structure required tracking the term structure curve daily and comparing current shape to historical norms. Data from NSE's options chain allowed traders to extract IVs across all available expiries and plot the structure. When the curve was unusually steep — near-month IV significantly above its historical average premium over far-month IV — sellers of near-month volatility via calendar spreads were considered well-positioned for mean reversion.
The introduction of multiple weekly expiries on Nifty added additional complexity to term structure analysis, as traders could now monitor IV differentials across current-week, next-week, month-end, and far-month contracts simultaneously. The ultra-short-dated weekly options near expiry exhibited extreme IV spikes in the final days that were structurally unrelated to the monthly or quarterly term structure.