Diagonal Spreads

A diagonal spread is what happens when a calendar spread meets a vertical spread. You use different strike prices AND different expirations. This gives you directional bias plus time decay — the best of both worlds.

The Structure

• Buy a longer-term option at one strike
• Sell a shorter-term option at a different strike
• Different expirations, different strikes

The most common version is a "poor man's covered call" (or "poor man's covered put"), where you buy a deep in-the-money LEAPS call and sell a short-term out-of-the-money call against it.

Real Example: Poor Man's Covered Call

NVDA is at $800. A covered call requires buying 100 shares ($80,000). You do not have that kind of capital. Enter the diagonal.

• Buy the 6-month $720 call (deep ITM) for $110.00 ($11,000)
• Sell the 30-day $830 call (OTM) for $18.00 ($1,800)

Net debit: $92.00 ($9,200)

Your long call has a delta of about 0.80, so it moves almost like stock. Your short call collects $1,800 in premium that decays over 30 days.

If NVDA stays below $830 in 30 days, the short call expires worthless. You keep $1,800 and still own the long call. That is a 19.6% return on the short call — in one month. Then you sell another call for the next month.

Why This Works

The deep ITM long call acts like a stock substitute. It costs $11,000 instead of $80,000 for 100 shares. You save $69,000 in capital. Meanwhile, you sell monthly calls against it just like you would with a covered call.

The long call has high delta (0.80) so it captures most of the upside. It has low theta so it does not decay much. The short call has high theta and decays quickly.

You are harvesting the time decay differential — the short option decays faster than the long option, just like a calendar spread. But you also have directional exposure because your long option is in-the-money.

Diagonal Put Spread Example

AMZN is at $185 and you are mildly bearish. You want to sell premium on the put side.

• Buy the 90-day $195 put (ITM) for $16.00
• Sell the 30-day $180 put (OTM) for $4.50

Net debit: $11.50 ($1,150)

If AMZN stays above $180, the short put expires worthless. You keep $450 and still own the long put. If AMZN drops to $175, both puts gain value but your ITM long put gains more.

Key Mechanics

Delta exposure. The diagonal has net positive delta (for call diagonals) or net negative delta (for put diagonals). You have a directional bias, which is different from a calendar that is delta-neutral.

Theta. The short option decays faster, generating daily income. As long as the stock does not blow through your short strike, time is your friend.

Vega. Like a calendar, the long option has more vega. Rising IV helps the position. Falling IV hurts it. Keep this in mind when entering.

Strike Selection

Long option: Go deep in-the-money. For calls, target a delta of 0.70 to 0.85. This means picking a strike 5% to 10% below the current price. The deeper ITM you go, the more the option behaves like stock but the more it costs.

Short option: Go out-of-the-money. For calls, target a delta of 0.20 to 0.30. This is typically 3% to 7% above the current price. You want a strike the stock is unlikely to reach before the short expiration.

Expirations: Long option 60 to 180 days out. Short option 20 to 45 days out. The bigger the gap, the more you benefit from the time decay differential.

Managing the Diagonal

Short option expires worthless. Sell another short-term option against your long. Repeat this cycle monthly.

Stock approaches the short strike. If NVDA rallies to $825 with 5 days left on the $830 short call, you have choices:

• Let it ride and hope it stays below $830
• Roll the short call up to $850 for the next month
• Close the entire diagonal for a profit

Stock drops significantly. If NVDA falls to $750, your long call loses value and the short call is nearly worthless. Close the short call for a small gain and decide whether to hold or close the long call at a loss.

Roll the short option. When the short option has decayed to 70% to 80% of its original value, consider rolling it out to the next month to collect fresh premium.

Advantages Over Covered Calls

The tradeoff is that the long call eventually expires. You need to manage it or roll it to a new expiration. Covered calls on stock can be held indefinitely.

Common Pitfalls

Long option too close to expiration. If your long call only has 30 days left, you lose the time decay advantage. Always keep at least 60 days on the long leg.

Short strike too close. Getting assigned on the short call is a headache with a diagonal. Keep the short strike above the long strike to maintain a defined-risk profile.

Ignoring assignment risk. If the short option goes in-the-money near expiration and has no time value left, early assignment is possible. Close before expiration to avoid this.

The diagonal spread is one of the most flexible strategies available. It combines income generation, directional exposure, and capital efficiency. Next: straddles and strangles for when you expect a big move but are not sure which direction.