Reversal Calculator

By Yojana Mandon · Updated June 2026 · 2 min read · Risk disclaimer

A reversal, or reverse conversion, shorts 100 shares and wraps them in a synthetic long — long a call and short a put at the same strike. Like the conversion it mirrors, the combined value is fixed regardless of price: a defined, near-riskless arbitrage built on put-call parity.

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Key characteristics

• Short stock + long call + short put at the same strike: a locked, flat payoff.
• The mirror image of a conversion — it profits from the opposite mispricing.
• Used to borrow stock synthetically or capture rich puts relative to calls.
• A market-maker / arbitrage structure, with only a tiny theoretical edge.

How a reversal works

The long call and short put at the same strike form a synthetic long stock. Pair that with your 100 short shares and the directional risk cancels, leaving a position fixed at the strike value at expiration — a flat payoff line.

A reversal pays when the put is rich relative to the call (after interest and dividends), the opposite condition to a conversion. It is also a way for market-makers to create a synthetic loan or to hold short stock with defined economics.

Risks and reality

The frictions mirror the conversion: three legs of commissions and spreads, borrowing costs and buy-in risk on the short shares, dividend obligations while short, and early assignment on the American-style short put, which breaks the lock.

Like conversions, reversals are mainly a professional inventory and financing tool and a textbook illustration of synthetics. After real-world costs there is rarely a net edge for retail traders.

On the Greeks, the Reversal is close to vega-neutral, so implied-volatility shifts have little net effect.

Managing the trade and common mistakes

Once a reversal is on, the position is theoretically locked — the long stock, long put, and short call at the same strike create offsetting exposures that leave almost no directional risk. In practice, the trade is held to expiration and closed by letting the legs expire or offset rather than actively managing delta. Profit-taking before expiration only makes sense if the mispricing collapses faster than anticipated and the combined bid-ask friction makes it worth exiting early; experienced traders calculate the round-trip cost carefully before legging out. If the arbitrage never fully closes, patience is the only real adjustment — rolling the structure to a later expiry is rarely worthwhile unless the same mispricing exists at the new date.

The most dangerous mistake beginners make is ignoring the cost-to-borrow on the long stock leg. If the underlying is hard to borrow, the stock-loan fee can erode or outright eliminate the arbitrage edge — an edge that already tends to be measured in cents per share. A second critical error is overlooking the dividend. Because the structure includes a short call, early assignment becomes highly probable just before an ex-dividend date: the call buyer will exercise to capture the dividend, leaving you suddenly short the stock and triggering margin calls or a forced buy-in. Always verify the dividend schedule and the borrow rate before putting the trade on, and consider closing the short call before the ex-date if assignment risk is elevated.

At expiration, pin risk is particularly acute for a reversal. If the stock closes exactly at the strike, neither the long put nor the short call has clear intrinsic value, and the decision to exercise or not exercise rests with the counterparty — you may end up with unexpected long or short stock exposure over the weekend. Close both option legs before the close on expiration day rather than letting them expire to avoid this. Liquidity is another structural constraint: reversals are primarily executed by market makers and institutional desks that can access tight borrow and navigate complex margin treatment; retail traders face wider spreads, higher borrow costs, and capital requirements that often make the apparent edge disappear entirely by the time all friction is accounted for.

Calculate it live

Use the free OptionProfit Reversal calculator to load a live option chain, build the trade, and instantly see the payoff chart, breakevens, probability of profit, Greeks and a Monte Carlo simulation of outcomes.

Frequently asked questions

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