Bear call spread

Definition

A bear call spread (short call vertical, credit) sells a call at a lower strike and buys a call at a higher strike, same expiry. It collects a credit for accepting capped, defined risk that the underlying finishes above the short strike — a neutral-to-declining thesis expressed as premium collection with a built-in hedge leg.

How it works / structure

• Legs: −1 call at K1, +1 call at K2 (K2 > K1), same expiry.
• Credit: net credit C; maximum loss (K2 − K1) − C; breakeven K1 + C.
• Payoff at expiry: at/below K1 keep C; at/above K2 lose max; between, lose (S − K1) − C.
• Parameters (engine-executable): short-strike delta (commonly 0.15-0.35 — distance vs premium tradeoff), width, DTE, credit threshold (credit/width floor; premium_per_delta_pctile), IV gate (iv_rank), management (mgmt-profit-target at x% of credit, mgmt-stop-loss at multiple of credit, mgmt-rolling up/out on strike tests, mgmt-time-based-exit at DTE floor).
• Greeks profile: net short delta, short vega, positive theta — the position earns from time and falling IV while the underlying stays below the short strike.

When it applies

Neutral-to-bearish theses with a defined invalidation level (the short strike is the thesis boundary), elevated IV conditions (opt-iv-rank-percentile), and as one half of an iron condor (strategy-iron-condor). The credit vertical’s appeal is that the thesis can be imprecise — “not above K1” — and still resolve profitably.

Risk profile & failure modes

• Asymmetric arithmetic: typical structures risk several times the credit; a modest hit rate is not enough — the win rate must clear the payoff ratio, which high-probability framing obscures (“collect small credits reliably” folklore).
• Gap-through risk: an overnight jump through both strikes realizes max loss instantly; stops cannot protect across gaps (ms-sessions-auctions).
• Upside squeeze: rallies against the position raise IV on the short leg and accelerate losses before expiry.
• Early assignment on the short leg around dividends converts the spread into short stock plus long call (ms-expiration-exercise-assignment).

Evidence & limits

Mechanics are contract arithmetic (OCC/Cboe). Aggregate premium- selling profitability rests on the volatility risk premium evidence (opt-implied-volatility), which is average-level, time-varying, and crash-punctuated; no public study establishes short call verticals specifically as a reliable excess-return class. Replay evidence per underlying and parameter set is the platform’s standard.

Falsifiable-thesis examples

Illustrations only, not signals:

• “X will close at or below K1 at expiry, expiring the K1/K2 call spread worthless” — falsified by a close above K1.
• “X will not trade above K1 at any point in the next 30 days” — falsified by any intraday print above K1.

Cross-references

• The other three verticals: strategy-bull-call-spread, strategy-bull-put-spread, strategy-bear-put-spread
• Composite: strategy-iron-condor
• Gates and math: opt-iv-rank-percentile, greek-theta, opt-expected-move
• Management: mgmt-profit-target, mgmt-stop-loss, mgmt-rolling