Ratio Calendar Spread
A calendar spread with unequal contracts — sell more short-term options than you buy long-term. Generates extra income but adds risk.
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What is a Ratio Calendar Spread?
A ratio calendar spread is a calendar spread where you sell more short-term options than you buy long-term options. A standard calendar spread is 1:1 — you buy one back-month option and sell one front-month option. A ratio calendar might be 1:2 — buy one back-month option and sell two front-month options.
The extra short option generates additional premium income, which reduces your cost or creates a credit. But it also adds risk because you have a naked short option after the front month expires (or if the stock moves too far).
Think of it as a turbo-charged calendar. More income, more risk. The sweet spot is still the short strike at the front-month expiration, just like a regular calendar. But the consequences of being wrong are amplified.
How to Set It Up
- Buy 1 longer-term option at strike A (back month)
- Sell 2 shorter-term options at the same strike A (front month)
- Same strike, different expirations
- Ratio: Commonly 1:2. More aggressive traders use 1:3, but the risk increases dramatically.
- Strike selection: At the money or near the current stock price. You want the short-term options to have maximum time decay.
- Front-month expiration: 20-45 days out.
- Back-month expiration: 60-120 days out.
- Net cost: Much less than a standard calendar. May be a credit depending on the ratio and IV.
At the front-month expiration, you want the stock to be at the strike price. Then one short option offsets the long option (like a standard calendar) and the extra short option expires worthless — you keep that premium.
When to Use This Strategy
Use a ratio calendar spread when:
- You expect the stock to stay near the current price through the front-month expiration
- You want more income than a standard calendar provides
- Front-month implied volatility is higher than back-month (volatility term structure inversion)
- You are comfortable managing the extra naked option risk
- You have a high-probability neutral thesis
This is an advanced strategy. The extra short option requires margin and creates risk if the stock moves too far. It is for experienced traders who actively manage positions.
Example Trade
Stock XYZ is trading at $100. You expect it to stay near $100 for the next month.
- Buy 1 XYZ $100 call (90 days out) for $6.00
- Sell 2 XYZ $100 calls (30 days out) for $3.50 each ($7.00 total)
- Net credit: $7.00 - $6.00 = $1.00 ($100 received)
At front-month expiration (30 days), if XYZ is at $100: Both short calls expire worthless. You keep $700 from selling them. You still own the 60-day-remaining $100 call, now worth roughly $4.00. Total position value: $400 + $100 credit = $500 profit (versus buying and selling). Close the long call or keep it.
If XYZ moves to $110 at front expiration: Two short calls cost $10 each ($20 total = $2,000). The long call is worth approximately $12. Net: $1,200 - $2,000 + $100 = -$700 loss. The extra short call killed you.
If XYZ drops to $90: Both short calls expire worthless ($700 kept). The long call is worth maybe $1.50 ($150). Net: $150 + $100 = $250 profit. Not bad — the ratio helped.
Risk and Reward
- Max profit: Varies and depends on the back-month option's value at front-month expiration. The ideal scenario is stock at the strike with maximum time value remaining in the back-month option.
- Max loss: On the upside, potentially significant because you have an extra naked short call. On the downside, limited to the net debit (or you keep the credit and the back-month option loses value).
- Breakeven: Complex to calculate because it depends on the remaining time value of the back-month option.
This is one of those trades where the P&L diagram is curved, not straight lines. The back-month option's remaining value creates uncertainty in the exact numbers.
Tips and Common Mistakes
- Manage the extra short option before expiration. If the stock moves toward the strike at front-month expiration, you may need to close or roll the extra short.
- The risk is the extra contract. Without it, you have a standard calendar. The extra short option is the whole point — and the whole risk.
- Keep the ratio conservative. 1:2 is aggressive enough. 1:3 or higher ratios create too much naked exposure for most traders.
- Front-month IV should be higher than back-month. This makes the short options relatively overpriced and the long option relatively cheap — maximizing your edge.
- Close the entire position if the thesis changes. Do not hold a losing ratio calendar hoping for a reversal.
Related Strategies
- Call Calendar Spread — the standard 1:1 calendar
- Ratio Diagonal — same concept with different strikes
- Call Ratio Spread — ratio within the same expiration
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