Most options strategies involve a trade-off: either you pay theta (long options) or you accept directional risk (short options). Calendar spreads break this rule — the short near-term leg earns theta FOR you, while the long back-month leg holds vega in case IV rises. It's the strategy that has time working for you on both legs simultaneously.
What You Will Learn
1. Calendar Spread Structure
The two legs
SELL near-term option (30 DTE, ATM) — positive theta, short vega
BUY longer-dated option (60 DTE, same strike) — negative theta, long vega
Net: Positive Theta (near leg decays faster), Long Vega (back leg dominates), Delta near zero at entry.
2. Live NIFTY Setup — spot 24,800
Call Calendar · Lot 25
BUY 60-DTE 24,800 CE · SELL 30-DTE 24,800 CE
Long 60-DTE call-₹295 × 25 = -₹7,375
Short 30-DTE call+₹205 × 25 = +₹5,125
Net debit-₹2,250
Max loss₹2,250
Max profit (at near-term expiry, NIFTY at 24,800)~₹3,500-4,500
Theta per day (net)+₹55 (short leg decays faster)
Vega per 1% IV rise+₹650
3. How It Profits
- Time passes, price stable: Short leg decays fully → keep full premium. Long leg still has time value → sell for profit.
- IV rises during the trade: Long leg gains more than short leg → profit even if price didn't move.
- Price moves away from strike: Both legs lose value, but differently. Losses cap at net debit paid.
4. When to Deploy
Ideal setup: IV Rank below 30 (cheap vega), no major move expected in near-term window, known catalyst in the 30-60 DTE window (will spike IV).
Common Indian use: Pre-earnings calendar on TCS/INFY. Sell near-term weekly, buy 30-DTE post-earnings expiry. Near leg eaten by theta; long leg protected against IV expansion.
Avoid: High IV Rank (vega already priced in). Strong trends (price moves away from strike). Less than 14 DTE on short leg (gamma-dominant).
Frequently Asked Questions
What is a Calendar Spread?
A Calendar Spread (also called a Time Spread or Horizontal Spread) is built by selling a near-term option and buying a longer-dated option at the same strike. The near-term leg decays faster (positive theta), while the longer-dated leg holds value (long vega). You profit from differential time decay plus any IV expansion.
How is it different from vertical spreads?
Vertical spreads (bull call, bear put, iron condor) use the same expiry with different strikes. Calendar spreads use the same strike with different expiries. Verticals bet on price direction; calendars bet on time passing AND (optionally) IV changes.
When does it profit?
Maximum profit occurs when the underlying is at the strike at near-term expiry. Near-term leg expires worthless (keep its premium), and the longer-dated leg still has value. Profits also occur from IV expansion — if volatility rises, the long leg gains more than the short leg.
What's the max loss?
Max loss = Net debit paid at entry. For a NIFTY 24,800 call calendar: buy 60-DTE 24,800 CE at ₹295, sell 30-DTE 24,800 CE at ₹205, net debit ₹90. Max loss = ₹90 × 25 = ₹2,250. Can happen if underlying moves far from strike by near-term expiry.
When should I use it?
Three conditions: (1) IV Rank is LOW (you want IV expansion), (2) You expect the underlying to stay near the strike for the near-term period, (3) You expect an upcoming catalyst (earnings, event) between the two expiries. Calendar spreads shine when IV is cheap and about to rise.
Can I use calendar spreads for directional bets?
Yes — use an OTM strike. A 'diagonal calendar' with an OTM strike lets you bet on direction (via delta) AND benefit from differential theta. More complex but powerful for skilled traders.
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