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Calendar Spread Strategy

Overview

A calendar spread (time spread, horizontal spread) exploits differences in time decay between options of different expirations. It involves selling a near-term option and buying a longer-term option at the same strike.

Difficulty intermediate Market Outlook: Neutral (short-term) with longer-term directional flexibility Risk Level: Low to moderate (defined risk)

Long Call Calendar Spread

Construction

Sell 1 near-term call (T1)
Buy 1 longer-term call (T2)
Same strike price (K)

Net Debit = Premium(T2) - Premium(T1)
Max Loss = Net Debit (if price moves far from K at T1 expiry)
Max Profit = When price ≈ K at T1 expiry (short expires worthless, long retains value)

where: T1 < T2 near and far expirations · K shared strike · Premium(T) market call premium at maturity T · Net Debit cost to enter (longer-dated always pricier). does: harvests faster theta decay of the short near-term leg while retaining vega on the long far-dated leg. Neutral / pinning short term with positive vega — ideal when front-month IV is high relative to back-month and you expect spot to stay near K through T1, then IV to rise or stay elevated past T1.

Payoff at Near-Term Expiration

Profit/Loss
  |           /\
  |          /  \
  |         /    \
  |        /      \
  |       /        \
  |      /          \
  |     /            \
  |    /              \
  |   /                \
  |  /                  \
  | /                    \
  |/                      \
--+---------K--------------\-- Stock Price
  |                        \
  v                         \
                            (Max Loss)

Long Put Calendar Spread

Sell 1 near-term put (T1)
Buy 1 longer-term put (T2)
Same strike price (K)

Similar payoff to call calendar (put-call parity).
Preferred when IV is expected to rise.

where: T1 < T2 near and far expirations · K shared put strike. does: put-call parity equivalent of the call calendar — same payoff shape at expiry. Neutral / pinning trade with positive vega; chosen over the call calendar when puts have richer IV or to avoid early assignment on ITM calls around dividends.

Double Calendar Spread

Sell 2 near-term options (different strikes)
Buy 2 longer-term options (same strikes)

Creates a wider profit zone.
Higher cost but more forgiving on price movement.

where: two strikes flanking spot — typically a put-calendar at lower strike and call-calendar at upper strike · same expirations across both legs. does: stacks two calendars to broaden the pin range into a tent — neutral / range-bound trade with elevated debit but wider tolerance on where spot lands at T1. Best when you expect a range but aren't confident on the exact center.

Entry Rules

  1. Market Conditions:
  2. Low near-term IV vs. higher longer-term IV (term structure opportunity)
  3. Range-bound market expected in near term
  4. IV expected to rise (benefits longer-dated option more)

  5. Front-month IV > back-month IV is unfavorable

  6. Strike Selection:

  7. ATM strike for maximum time decay differential
  8. Slightly OTM if directional bias exists

  9. Consider where you expect price to be at T1 expiry

  10. Expiration Selection:

  11. Near-term (T1): 2-4 weeks
  12. Longer-term (T2): 1-3 months
  13. Ratio T2/T1: 2:1 to 4:1 optimal

  14. Avoid weekly-to-weekly calendars (too much gamma)

  15. Debit Target:

  16. Minimize net debit
  17. Target: Debit < 20% of underlying price

Exit Rules

Scenario Action
Near-term expires worthless Hold long option, sell new near-term
50%+ of max theoretical profit Close entire spread
Price moves far from strike Close at loss or roll strike
IV rises significantly Hold (long option benefits more)
IV drops significantly Close (both options lose value)

Position Sizing

Example:
Stock: $100
Sell 30-day $100 call: $3.00
Buy 60-day $100 call: $5.50
Net Debit: $2.50

Max Loss: $250 per spread
Max Profit: ~$200-300 (depends on IV at T1)
Return on Risk: 80-120%

Position sizing: Risk 1-2% per trade

Expected Performance

Metric Value
Win Rate 55-65%
Risk-Reward 1:1 to 1:1.5
Best Market Low vol, price near strike
Worst Market Large directional move, IV crush
Theta Positive (net) if near-term decays faster
Vega Positive (longer-dated option has higher vega)

Greeks Exposure

Greek Calendar Spread Interpretation
Delta Near zero (ATM) Neutral, shifts as price moves
Gamma Negative (near expiry) Accelerates losses on moves near T1
Theta Positive Near-term decays faster than long-term
Vega Positive Longer-dated option has higher vega

Rolling Strategy

When the near-term option expires:

1. If short expires worthless:
   - Long option still has time value
   - Sell another near-term option against it
   - Collect additional premium

2. If short is ITM at expiry:
   - Close long option to limit losses
   - Or roll both legs to new expiration
   - Accept loss if thesis invalidated

Checklist

  • [ ] Near-term IV > longer-term IV (favorable term structure)
  • [ ] Strike aligned with expected price at T1 expiry
  • [ ] Time ratio T2/T1 between 2:1 and 4:1
  • [ ] No earnings/events during T1 period
  • [ ] Net debit acceptable relative to max profit potential
  • [ ] Exit plan: profit target, stop-loss, time-based exit
  • [ ] Plan for rolling after T1 expiry

Assumptions & Limitations

  1. Profit zone is narrow — price must stay near strike
  2. Requires two transactions to establish and potentially more to roll
  3. Commissions reduce edge significantly
  4. Early assignment on short option can disrupt the spread
  5. IV term structure must be favorable
  6. Not ideal for trending markets

References

  1. Hull, J.C. (2022). Options, Futures, and Other Derivatives (11th ed.). Pearson.
  2. McMillan, L.G. (2013). Options as a Strategic Investment (5th ed.). NYIF.
  3. Natenberg, S. (2023). Option Volatility and Pricing (3rd ed.). McGraw-Hill.