Call Ratio Spread

Quick answer: A Call Ratio Spread buys one call and sells two higher-strike calls of the same expiry, usually for a net credit; because it is net short one call, the loss above the short strikes is genuinely unlimited.

In simple words

You buy one call and sell two higher calls, usually taking in a small credit. If the market drifts up to the higher strike you do well, because the call you own gains while the two you sold have not yet turned against you. But past that strike the extra sold call has no cover, and your loss grows without any limit as the market keeps rising. This is not a safe income trade. It is a bet that the market rises only a little, and it hides an open-ended risk that can dwarf the credit collected many times over if the rally continues.

Payoff diagram

Professional explanation

Why it is undefined-risk

The position holds one long call and two short calls of a higher strike. Below the short strike the long call and the first short call broadly offset, and the trade behaves calmly. Above the short strike, though, only one of the two short calls is covered by the long call — the second is naked. A naked short call has genuinely infinite loss, because the underlying can rise without bound and the obligation grows with it. That surviving unhedged short call is why a ratio spread is undefined-risk, and why it is fundamentally different from the backspread it is often confused with, which is net long and defined-risk.

The profit tent and its peak

Plotted at expiry the payoff is a tent. From the credit at low prices it rises to a peak exactly at the short strike, where the long call is fully in the money and both short calls are still worthless. Past the short strike the two short calls begin to bite and the profit falls, crossing zero at the upper breakeven and then turning into an ever-deepening loss. The peak is the width between the strikes plus the credit. The whole appeal is a market that lands near the short strike at expiry; the whole danger is a market that keeps going.

A ratio spread is not a backspread

These two are constantly muddled. A ratio spread sells more options than it buys — it is net short, takes in a credit, and has undefined risk. A backspread buys more than it sells — it is net long, pays a debit, and has defined risk with unlimited profit on a strong move. They are mirror images: the ratio spread wants a small move and fears a large one, while the backspread wants a large move and merely bleeds the debit on a small one. Selling two and buying one is a ratio spread; buying two and selling one is a backspread.

Margin and assignment reflect the naked leg

Because a ratio spread carries an uncovered short call, brokers charge naked-option margin on the unhedged leg, not tidy spread margin — the capital requirement is high and can rise sharply if the underlying approaches the short strike. On stock options either short call can be assigned early, and above the strike the naked one delivers short stock with no cover. On cash-settled index options there is no assignment, but the unlimited tail at settlement is fully real. This is a position that demands active management and cannot simply be left to expire when the underlying is near or above the short strike.

Construction

1. Buy one lower-strike call of the chosen expiry.
2. Sell two higher-strike calls of the same expiry, typically taking in a net credit.
3. Recognise that one of the two short calls is uncovered, so the upside risk is unlimited.

Market outlook

A trader may study a call ratio spread when expecting the underlying to drift up modestly toward a level and stall there, with implied volatility rich enough that the two short calls fund the long one for a credit. The peak profit sits at the short strike. The view is invalidated by a strong rally beyond the short strikes, where the uncovered call produces unlimited loss, or by a volatility spike that inflates the short calls. It is not a passive income structure; it demands a hard ceiling on how far the underlying can rise and constant attention, because the failure mode is open-ended rather than capped.

Risk profile

This is an undefined-risk position, and the loss above the short strikes is genuinely unlimited. The single long call covers only one of the two short calls; the second is naked, so as the underlying rises without bound the loss does too. There is no structural cap — nothing in the position stops the payoff falling as the underlying goes to infinity. On the downside the risk is limited to a small loss or the credit, but that benign tail is not the point: the defining feature is the uncovered short call and the open-ended loss it carries, which is why margin is charged as if on a naked position.

Reward profile

The maximum profit is the strike width plus the net credit, reached only if the underlying settles exactly at the short strike at expiry, where the long call is fully valued and both short calls expire worthless. Away from that peak the reward falls off on both sides — toward the credit below the long strike and toward unlimited loss above the upper breakeven. The reward is therefore sharply path-dependent and concentrated at one price, in exchange for accepting an open-ended tail.

Margin requirement

Because one short call is uncovered, the exchange and brokers charge naked-option margin on the unhedged leg rather than spread margin, so the capital requirement is high and rises as the underlying nears the short strike. SPAN plus exposure can increase intraday. This is not a defined-risk spread for margin purposes. NSE and brokers revise margin rules periodically, so confirm the current requirement before trading.

Greeks exposure

The sign on each Greek above is computed, not asserted: it is the net exposure of the illustrative legs at spot 24,000 with 30 days to expiry, priced with Black–Scholes using each leg's implied volatility calibrated from its own quoted premium. A sign can flip as the underlying moves — the panels below show where. See Methodology.

Volatility impact

The position is net-short vega, so rising implied volatility works against it — the two short calls inflate faster than the single long call, worsening the mark even before price moves. A volatility spike is especially dangerous because it usually accompanies the very rally that threatens the uncovered leg, so vega and direction turn hostile together. Falling volatility helps and is part of why the trade is opened when premiums are rich. But the volatility comfort is secondary to the structural tail: no amount of favourable volatility removes the unlimited loss that a strong rally produces beyond the upper breakeven.

Time decay

Time decay works for the position while the underlying stays below the short strike, because more options are sold than bought and net theta is positive. Each quiet day erodes the two short calls in the trader's favour faster than the long call. That benefit is why the tent peaks at expiry. But near expiry, if the underlying is close to the short strike, gamma is large and negative — small moves swing the profit and loss violently, and a late push through the strike converts a decaying winner into an accelerating, uncapped loss.

Practical examples

Lot sizes used above (NIFTY 75, BANKNIFTY 30) are those in force at the time of writing; NSE revises them periodically. Figures exclude brokerage, STT, exchange charges, stamp duty and GST, all of which materially affect small spreads.

Common mistakes

• Believing the credit measures the risk, when the true risk above the upper breakeven is unlimited and can exceed the credit many times over.
• Confusing it with a backspread: this sells two and buys one, so it is net short and undefined-risk, not the net-long, defined-risk backspread that profits from a big move.
• Leaving the position unmanaged into expiry with the underlying near the short strike, where a late push through it converts a decaying winner into an accelerating loss.
• Underestimating the margin, which is naked-option margin on the uncovered leg and can rise sharply as the underlying approaches the short strike, forcing a poorly timed exit.
• Opening it in low implied volatility, where the credit is too small to justify carrying an open-ended tail.
• On stock options, ignoring early assignment of a short call, which above the strike delivers short stock with no cover and turns the trade into an open directional loss.

Advantages & disadvantages

Adjustments & exits

• Buying a further-out call against the naked short converts the position into a defined-risk structure such as a Christmas tree or broken-wing butterfly, at the cost of some credit.
• Rolling the short calls up and out as the underlying rises lifts the danger zone, but adds risk and offers no assurance of escaping the tail.
• Closing one of the two short calls removes the uncovered leg entirely, leaving a plain bull call spread with defined risk and a smaller position.
• Taking the whole trade off as the underlying approaches the short strike near expiry avoids the violent gamma and the open-ended tail beyond it.

Adjustment is a decision about risk, not a way to rescue a losing view. See Adjustments and Exit Planning.

Professional usage

Volatility desks use ratio structures to fine-tune exposure across a book, often as one component of a larger position rather than a standalone bet, and they can hedge the uncovered wing dynamically with futures or further options in ways retail cannot easily replicate. The credit and negative vega express a view that the underlying stalls and volatility eases, while the desk manages the tail with size limits and offsetting positions. For a retail trader without that infrastructure, the open-ended risk and rising naked margin make the ratio spread one of the least forgiving structures to carry unmanaged.

Frequently asked questions

Voice search & related questions

Natural-language questions people ask about the Call Ratio Spread.

Sources & references

• NSE — Derivatives
• S. Natenberg, Option Volatility and Pricing
• L. McMillan, Options as a Strategic Investment

Last reviewed 9 July 2026. Educational content only — not investment advice.