Credit spreads: defined risk, paid up front.

Put credit spreads: the bullish-to-neutral workhorse

A put credit spread (bull put spread) sells a put below the current price and buys a further-out put as protection, collecting a net credit. The position keeps the full credit if the underlying finishes above the short strike at expiration — which means it profits if the stock rises, drifts sideways, or even falls modestly. You are not predicting a rally; you are underwriting the claim “probably not below X by this date.”

The long put is what makes the structure defined-risk: no matter how far the underlying falls, the loss is capped at the strike width minus the credit. That floor is why put credit spreads can be sized precisely and traded systematically, while naked short puts require reserves for the full move to zero.

Call credit spreads: the bearish mirror

A call credit spread (bear call spread) sells a call above the market and buys a further-out call, keeping the credit if the underlying stays below the short strike. It is the tool for expressing “probably not above Y” — after an extended run into resistance, when IV is elevated, or as the upper half of an iron condor.

Two asymmetries make call spreads the harder side. Equity indexes drift upward over time, so the short call fights a structural current the short put does not. And short in-the-money calls carry ex-dividend assignment risk: if the dividend exceeds the call's remaining extrinsic value, early assignment becomes rational for the counterparty. Check the dividend calendar before selling call spreads on dividend payers.

Strike selection by delta

Delta doubles as a rough, live estimate of the probability an option expires in the money, which makes it the natural dial for strike selection. Selling a 0.30-delta strike means roughly a 30% chance the short strike is breached at expiration — about a 70% chance of keeping the credit. Selling 0.20 delta pushes that toward 80%, with a correspondingly smaller credit.

The conventional bands: 0.20–0.30 delta for standard premium-selling entries, 0.15 and below for conservative structures like condor wings, 0.35+ only when the trade is explicitly directional. Width is the second decision: wider spreads collect more credit but risk more per contract; narrower spreads cap risk tighter but pay proportionally more of the credit away for the protection.

POP vs credit: the tradeoff you cannot escape

Probability of profit and size of credit are two ends of the same rope. Move the short strike further from the money and POP rises while the credit shrinks — you win more often and make less each time, while the occasional max loss stays nearly as large. Move it closer and the credit fattens while POP falls. There is no strike that gives you both; option pricing exists precisely to enforce this.

The honest way to compare candidates is expected value: (POP × credit kept) minus (probability of loss × average loss). A 90% POP trade that collects $0.35 against $4.65 of risk is negative-EV the moment losers average anywhere near max loss. High win rates are seductive and mean nothing by themselves — the question is always whether the credit is adequate compensation for the tail you are underwriting.

Risk/reward math: a worked example

The stock trades at 148 after an earnings-driven IV spike. You sell the 140/135 put credit spread at 35 days to expiration for $1.25. Every number that matters is known before entry:

Two things to notice. First, the max loss is three times the max profit — the structure only works because wins are far more frequent than losses. Second, the positive expected value in this example depends on the management rule: letting losers routinely run to the full $375 max loss flips the arithmetic. The management framework is not an accessory to the strategy; it is the strategy.

Management: 50% profit, 2x stop, 21 DTE

Take profits at 50% of the credit received. The first half of the profit arrives fastest; the second half requires holding through the highest-gamma stretch of the trade for a diminishing daily reward. Closing at 50% recycles capital into fresh, higher-theta positions and measurably cuts the frequency of large losses over many occurrences.

Cut losers when the loss reaches about 2× the credit collected — on a $1.25 credit, close near a $2.50 loss. This keeps the worst realized outcomes near two units of profit instead of three, and forces the exit decision to happen by rule, while it is still cheap, rather than by hope. Rolling out in time for a net credit is acceptable when the original thesis is intact; rolling for a debit is buying more time to be wrong.

And manage the calendar: by roughly 21 DTE, close or roll regardless of profit. Inside three weeks, theta gains are increasingly paid for with gamma risk — one adverse move can turn a comfortable winner into a breached strike faster than any adjustment can respond.

When NOT to trade credit spreads

Skip low-IV environments: when IV rank is under ~30, credits are thin and the same strikes pay a fraction of what they pay in rich conditions — you take on identical tail risk for less compensation. Skip binary events: earnings, FDA decisions and similar catalysts can gap the underlying straight through both strikes, and no stop-loss rule executes through a gap.

Skip illiquid chains — wide bid/ask spreads on four legs of round-trip execution can consume most of the theoretical edge — and skip strong trends against your direction: selling call spreads into a persistent uptrend “because it's extended” is a fight the base rate usually wins. Finally, skip trades whose max loss exceeds your per-trade risk cap. A credit spread that is too big for the account is not a smaller opportunity; it is a different, worse trade.

• What is the probability of profit?
• What is the probability of touching the short strike?
• What is the probability of hitting 50% max profit?
• What is the probability of max loss?
• Is this trade positive expected value?

• Should I buy premium or sell premium?
• Should I use a debit spread or credit spread?
• Is an iron condor appropriate?
• Is the expiration too short?
• Are the strikes too aggressive?
• Is this a better trade as a spread instead of a naked option?

• When should I take profit?
• When should I stop out?
• Should I close before earnings?
• Should I roll?
• Should I adjust or exit?