Risk Reversal: Directional Strategy, Skew Quote, and Assignment Risk

For educational purposes only; not investment advice.

Direct answer

Risk reversal has two related but distinct meanings. As a directional option strategy, a bullish risk reversal buys a Call and sells a Put on the same underlying and expiration, usually with the Call strike above the Put strike. The bearish version buys the Put and sells the Call. The premium received from the short leg helps finance the long leg, but it also creates a substantial obligation in the adverse tail.

As a volatility quote, a risk reversal compares matched-Delta Call and Put implied volatilities, commonly at 25 Delta. A convention might report IV(25Δ Call) − IV(25Δ Put), while another vendor may reverse the sign or use a ratio. This quote describes skew, not the profit of one universal strategy. Always record the exact convention.

Strategy payoff and skew meaning

For a bullish structure with short Put strike Kₚ, long Call strike K꜀, Kₚ < K꜀, and initial net credit c per share, expiration P&L before costs is:

S_T < Kₚ: P&L = S_T − Kₚ + c

Kₚ ≤ S_T ≤ K꜀: P&L = c

S_T > K꜀: P&L = S_T − K꜀ + c

If the trade is entered for a net debit D, substitute c = −D. A credit does not cap downside loss: if the stock goes to zero, the short Put loss is approximately Kₚ − c per share. Upside above the Call strike is theoretically unlimited. With a debit, the central region loses the debit and the valid upper break-even is K꜀ + D; formulas must be checked against their piecewise region rather than quoted mechanically.

When Call and Put share the same strike, long Call plus short Put is synthetic long stock for the option term under put-call parity, adjusted for financing and dividends. Separating the strikes inserts a flat payoff region between them. A collar adds a stock position and therefore is not the same two-leg trade.

In volatility analysis, a more negative Call IV − Put IV indicates richer downside Put volatility relative to upside Call volatility under that convention. It can reflect protection demand, crash-risk pricing, supply, inventory, and liquidity. It is not a pure probability or sentiment reading.

Bullish risk reversal for a credit

Assume the stock is $100. For one expiration:

sell one 95 Put for $2.80 per share;
buy one 105 Call for $2.20 per share;
net credit c = $0.60 per share, or $60 with a standard 100-share multiplier.

Expiration outcomes before fees:

Stock at expiration	Put result	Call result	Total P&L per share
`$0`	`−$95.00`	`$0`	`−$94.40`
`$90`	`−$5.00`	`$0`	`−$4.40`
`$94.40`	`−$0.60`	`$0`	`$0`
`$100`	`$0`	`$0`	`+$0.60`
`$105`	`$0`	`$0`	`+$0.60`
`$115`	`$0`	`+$10.00`	`+$10.60`

The lower break-even is $95 − $0.60 = $94.40. Maximum theoretical loss is $94.40 per share, or $9,440 per one-lot, if the stock becomes worthless. The initial “zero-ish cost” is therefore not limited risk. At $90, assignment on the short Put can require purchasing 100 shares at $95, a $9,500 cash obligation before considering the option credit.

For a separate skew observation, if a matched 25Δ Call has IV 22% and the 25Δ Put has IV 28%, the Call minus Put risk reversal is 22% − 28% = −6 volatility points. Under the opposite sign convention it would be +6; the economics have not changed.

Construction and risk checklist

Write each leg, strike, expiration, quantity, style, settlement, deliverable, and multiplier before naming the strategy.
State whether the net premium is a credit or debit and include complex-order Bid/Ask and all fees.
Calculate piecewise P&L; one break-even formula may lie outside the region where it applies.
Reserve cash or margin for the short Put or short Call obligation under severe moves.
American-style short options can be assigned early; the long opposite-type option does not automatically neutralize that assignment.
Check dividend, borrow, corporate-action, and expiration risks that can alter exercise behavior and deliverables.
Use one complex limit order where feasible; legging can leave an uncovered option.
Compare same expiration and matched Delta when interpreting a volatility risk-reversal quote.
Record whether the quote is Call minus Put, Put minus Call, a ratio, or a premium amount.
Do not infer customer direction from skew alone; dealer inventory and hedging demand are not fully observable.
Stress spot, IV level, skew rotation, time decay, spread widening, and a failed exit simultaneously.
Treat rolling as closing the old position and opening a new one with fresh tail risk.

Common misconceptions

“Risk reversal has one universal definition.” It can mean a strategy or a skew quote, with varying sign conventions.
“Zero-cost means zero-risk.” Short-option tail exposure can be far larger than the premium exchanged.
“The short Put merely pays for the Call.” It creates a purchase obligation if assigned.
“The bullish structure has stock-like P&L everywhere.” Different strikes create a flat middle region.
“It is the same as a collar.” A protective collar also includes long stock.
“A negative 25-Delta risk reversal is bearish probability.” It is a relative IV price containing premiums and market frictions.
“The Call protects an assigned Put.” A Call gives a right to buy; it does not fund or cancel a short Put assignment.
“Defined entry premium defines maximum loss.” The short tail, not the initial premium, determines maximum strategy loss.