Long Box Spread
A bull call spread combined with a bear put spread at the same strikes — producing a fixed payoff at expiration regardless of price. A pure arbitrage structure.
Profit / Loss Diagram
Long Box at expiration — fixed payoff
What is this strategy?
The Long Box Spread — often simply called a <strong>Box</strong> — is a pure arbitrage structure combining a Bull Call Spread with a Bear Put Spread at the same strikes. Construction: buy an ITM call, sell an OTM call, sell an ITM put, buy an OTM put, all at the same expiration.
The result: the payoff at expiration is <em>fixed</em> and equal to the difference between strikes, independent of the underlying price. If you pay less than that difference — say $20 for a $25-wide box — the difference is a guaranteed profit.
The Box Spread is used mainly as a financing vehicle: institutional traders use it to borrow or lend at rates implied in options prices, typically competitive with benchmark rates. For retail traders it rarely justifies the transaction costs, though it can be useful for specific margin situations.
Construction
| Action | Instrument | Strike | Expiration | Example |
|---|---|---|---|---|
| BUY | 1 Call | Lower strike | 60-180 DTE | +1 SPY 440 Call |
| SELL | 1 Call | Higher strike | Same expiry | -1 SPY 460 Call |
| SELL | 1 Put | Lower strike | Same expiry | -1 SPY 440 Put |
| BUY | 1 Put | Higher strike | Same expiry | +1 SPY 460 Put |
Example
SPY at any price. You build a 440/460 box, 20 points wide, paying a debit below that width.
- Net Debit $1,980
- Fixed Payoff at Expiration +$2,000 (always, whatever the price)
- Guaranteed Profit +$20 ($2,000 − $1,980) — around 2% annualised over 180 days
The Greeks
A completely neutral position by construction.
Time does not affect it — the payoff at expiration is fixed.
Volatility does not affect it — the payoff is fixed.
No directional sensitivity.
Position Management
- 01 Hold to Expiration The box settles automatically at expiration to its fixed payoff.
- 02 Only With Low Costs For retail traders, commissions on four legs can destroy the small margin. Only viable with zero commissions or at large size.