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Short Calendar Put Spread

The all-puts version of the Short Calendar — buy the near-dated leg, sell the longer-dated one. Positive gamma with risk concentrated at the strike.

Max GainNet credit received ($500 in the example)
Max LossCapped — the value the sold long-dated leg retains when the purchased one expires worthless, with the underlying at the strike
Break-evenTwo points around the strike — no closed formula (they depend on the residual value of the sold long-dated leg)
TypeSmall net credit
Ideal IV environmentHigh IV with expectation of compression — it is the inverse of the long calendar

Profit / Loss Diagram

Short Calendar Put at the short expiration

Common strike Profit Profit Loss (at strike)

What is this strategy?

The Short Calendar Put Spread is the puts version of the Short Calendar Call. Same profile: positive gamma and negative vega, with maximum loss concentrated at the strike when the purchased leg expires.

Useful when puts carry better liquidity than calls, as on large indices ahead of events.

An advanced structure — only for traders who understand the term structure of implied volatility.

Construction

ActionInstrumentStrikeExpirationExample
BUY1 PutATM (same strike)Front (30 DTE)+1 SPY May 450 Put
SELL1 PutATM (same strike)Back (60-90 DTE)-1 SPY Jul 450 Put

Example

SPY at $450 ahead of an FOMC decision with high IV. Short Calendar Put at the 450 strike.

  • Long May 450 Put −$300 premium paid
  • Short Jul 450 Put +$800 premium received
  • Net Credit +$500
  • Maximum Gain $500 (the credit) if SPY moves away from the strike or IV compresses
  • Maximum Loss $200 to $300 — what the July put retains when the May put expires worthless with SPY at $450

The Greeks

δDelta — Neutral

Same as the Short Calendar Call.

θTheta — Negative

Same.

νVega — Negative

Negative vega, like the Short Calendar Call: it benefits from a compression in implied volatility.

γGamma — Positive

Positive gamma: the purchased near-dated leg dominates. It profits from a fast move.

Position Management

  1. 01
    Same as the Short Calendar Call Close before the near-dated expiration.

Frequently Asked Questions

When should this structure be opened?
With implied volatility high and an expectation of compression, or ahead of an expected strong move. It collects a credit and profits if price moves away from the strike.
What is its main risk?
That the underlying stays at the strike when the near-dated leg expires, which is where maximum loss occurs.
How is it managed before expiration?
By closing early once the move or the expected volatility compression arrives, rather than carrying it to the long expiration.
Which strategy is it most often confused with?
The long put calendar, of which it is the inverse in every parameter.
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Related Terms

Short Calendar Call SpreadLong Calendar Put Spread