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A genuinely different kind of strategy from everything else on this site: a four-leg combination whose payoff is fixed at expiry, regardless of where the underlying finishes. It isn't a directional or volatility bet at all — it behaves more like a synthetic loan or deposit.

A Box Spread combines a Bull Call Spread and a Bear Put Spread, both built on the exact same two strikes and expiry. Individually, each of those two spreads has its own payoff that depends on where the underlying ends up. Combined, though, their price-dependent parts exactly cancel out, leaving only a fixed value equal to the width between the two strikes, minus what was paid to enter the position.

Legs 1 and 2 are a Bull Call Spread. Legs 3 and 4 are a Bear Put Spread. Put them together on the same two strikes and the underlying's actual price at expiry stops mattering — the combination is worth the strike width, always.

Unlike every other strategy on this site, there's only one "zone" — the payoff is the same everywhere:

1. At any price, anywhere — the position is worth exactly the width between the two strikes, no more and no less. This was confirmed directly across a wide range of prices, not just assumed from the theory.

Because the payoff is fixed and known in advance, the entire "return" on a Box Spread comes from the difference between what you paid to enter it and that fixed final value — functionally similar to buying a bond or a fixed deposit at a known rate, using options instead of a lender.

A Box Spread isn't used to express a view on the underlying at all — it's a way to borrow or lend money synthetically using the options market, often for arbitrage or financing purposes rather than as a speculative position. If the net cost to enter is less than the strike width discounted appropriately, it can represent an effective way to lend money at a fixed rate (and vice versa for borrowing) — this is a genuinely specialized use case, not a typical retail directional trade.

Suppose Nifty is trading at 24,000 with a weekly expiry coming up, and lot size is 65.

1. Buy 1 call at the 24,000 strike for a premium of 145.
2. Sell 1 call at the 24,300 strike, collecting a premium of 60.
3. Buy 1 put at the 24,300 strike for a premium of 140.
4. Sell 1 put at the 24,000 strike, collecting a premium of 58.
5. Calculate the net cost: (145−60) + (140−58) = 167 points, or ₹10,855 at this lot size — what you pay to enter the position.
6. Calculate the fixed payoff: the strike width is 300 points, so at expiry the position is worth 300 × 65 = ₹19,500, regardless of where Nifty finishes.
7. Calculate the net result: ₹19,500 (fixed payoff) − ₹10,855 (cost) = ₹8,645 — this is the profit, no matter where Nifty settles.
8. See how it resolves at expiry:
   • Nifty finishes at 22,000 → profit of ₹8,645.
   • Nifty finishes at 24,150 (right between the strikes) → profit of ₹8,645, exactly the same.
   • Nifty finishes at 26,000 → profit of ₹8,645, still exactly the same.

Quick reference for the same trade:

Based on the worked example above. Unlike every other diagram on this site, this one is a perfectly flat, horizontal line — confirming the payoff really is the same at every price, not just approximately similar. Move the cursor over the chart to see profit/loss at any price.

• Real-world execution can introduce risk this simplified example doesn't have. Bid-ask spreads across four separate legs, and the risk of not getting all four filled at consistent prices, can eat into or even eliminate the theoretical fixed return.
• This is a specialized, low-retail-relevance strategy. It's primarily used for financing and arbitrage purposes, not as a way to express a market view.
• Margin and capital requirements can be significant across four simultaneous legs, even though the net risk is theoretically minimal once filled.
• Index options on NSE are typically European-style and cash-settled — no early-assignment risk on the short legs before expiry.