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.
Profit / Loss Diagram
Short Calendar Put at the short expiration
What is this strategy?
The Short Calendar Put Spread is the puts version of the Short Calendar Call. Same profile: <strong>positive gamma and negative vega</strong>, 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
| Action | Instrument | Strike | Expiration | Example |
|---|---|---|---|---|
| BUY | 1 Put | ATM (same strike) | Front (30 DTE) | +1 SPY May 450 Put |
| SELL | 1 Put | ATM (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
Same as the Short Calendar Call.
Same.
Negative vega, like the Short Calendar Call: it benefits from a compression in implied volatility.
Positive gamma: the purchased near-dated leg dominates. It profits from a fast move.
Position Management
- 01 Same as the Short Calendar Call Close before the near-dated expiration.