Credit spreads explained: payoff, costs and assignment
A credit spread exchanges some premium for a protective option. Learn to calculate its expiration payoff, compare risk using dollars rather than headline percentages, and understand why managing both legs matters.
By OptionsKing. Publisher and editorial methods.
What you will learn
By the end of this lesson, you should be able to:
- Calculate credit, break-even, and maximum expiration loss for a vertical spread.
- Distinguish maximum potential return from a forecast or expected return.
- Explain how assignment and an expired protective leg can create stock exposure.
A call credit spread sells a lower-strike call and buys a higher-strike call with the same expiration and multiplier. The long call limits the combined options' expiration loss, provided the position is kept intact and settled or closed appropriately. The opening credit is cash received, not yet profit.
The trade
Chipotle (CMG) at $38.40, September 19 expiry, 45 days out. Same chain as the chain page.
| Leg | Action | Price | Delta | Cash |
|---|---|---|---|---|
| $42 call | sell 1 | $0.73 | 0.268 | +$73 |
| $44 call | buy 1 | $0.35 | 0.153 | -$35 |
| Net | $0.38 | 0.115 | +$38 |
- Credit: $38, yours the day it fills.
- Width: $2 between the strikes, so $200 per contract.
- Maximum loss: $200 minus the $38 credit = $162. This is the intact spread's maximum expiration loss before costs, not a guarantee about stock exposure left after exercise or assignment.
- Break-even: $42.38.
- Return on risk: 23.5 percent in 45 days.
What the wing costs
Here is the whole page in two numbers. Sell the $42 call on its own and you collect $73. Buy the $44 to cap it and you give back $35.
That is 47.9 percent of the gross premium, spent on protection that starts paying intrinsic value above $44 at expiration. The spread begins losing below that point, once CMG exceeds the $42.38 break-even.
The $35 wing has its own price and implied volatility. Its presence reduces tail exposure but also reduces the credit. A model-derived price is an illustrative valuation, not proof that the option is cheap, expensive, or exactly fair.
So the reason to buy the wing is not that it is cheap. It is that a naked short call has a loss with no bottom line on the table, and one takeover announcement inside 45 days is enough. The purpose of the wing is to change the loss distribution and capital requirement, not to establish a trading edge.
Where it ends up
For this call spread, expiration P/L per share is $0.38 - max(S - $42, 0) + max(S - $44, 0). Below $42 you keep the credit; between the strikes the short call loses value dollar for dollar; above $44 the two intrinsic values offset except for their $2 width. Multiply by 100 for one standard spread.
| CMG at expiry | Result | P and L | Odds |
|---|---|---|---|
| Below $42 | both expire worthless | +$38 | 75.6% |
| $42 to $42.38 | short call in the money, still ahead | +$1 to +$37 | 2.0% |
| $42.38 to $44 | losing, partially | -$1 to -$162 | 7.4% |
| Above $44 | both in the money, spread at full width | -$162 | 14.9% |
Under this illustrative model, about three quarters of outcomes keep the full credit and about one in seven reaches maximum expiration loss. These are model probabilities, not observed win rates. A zero-value risk-neutral pricing calculation is not a forecast of actual investment returns.
One note on the odds column, because two numbers on this site disagree and the disagreement is real. The $42 strike's own implied volatility of 35.3 percent prices it as a 22.9 percent chance of finishing in the money. The table above, which needs one volatility for the whole distribution, uses the at-the-money 38.4 percent and gets 24.4 percent. The 1.5 point gap is skew, showing up as an inconsistency you cannot model away with a single number.
Against a covered call, on the same view
The positions have different directional exposures. The call spread benefits if CMG stays below its short strike; the covered call owns stock and can lose heavily when CMG falls. Similar upper price levels do not make the trades equivalent.
| $42/$44 call spread | Covered call, $43 strike | |
|---|---|---|
| Capital required | $162 | $3,840 of stock |
| Credit | $38 | $49 |
| Return on capital, 45 days | 23.5% | 1.28% |
| Annualized | 190% | 10.4% |
| Worst case | -$162 | -$3,791 if CMG goes to zero |
| Upside if it rallies | none | $460 of appreciation to the strike |
| Dividends, votes, holding | none | yours |
That 190 percent number is why credit spreads get sold hard, and it is doing something dishonest. The denominator is $162 because the risk is $162, and the absolute dollars are lower than the covered call's. $38 against $49. A percentage return on a tiny base is not more money.
The real arguments for the spread are the other rows. You do not need $3,840. You are not left owning a stock you did not want. The worst case is a number you can write down before you place the trade, which is the thing position sizing actually needs.
The real arguments against are the last two. You never own the shares, so there is no dividend, no long-term holding period, nothing to wheel, and no version of the trade where being wrong leaves you holding something you wanted anyway.
Four things that go wrong
Both legs cross a spread. Twice on the way in, twice on the way out. Send it as a single spread order with one net limit rather than legging in, and start at the net mid of $0.38. Legging in on a moving chain is how a $38 credit becomes a $31 credit.
Early assignment on the short leg. These are American-style contracts. If the $42 call is assigned early you are short 100 shares, with a long $44 call as your only protection, which can create a margin requirement and requires prompt management. Read the extrinsic-value discussion and monitor exercise incentives throughout the position, especially around ex-dividend dates.
Pin risk between the strikes. CMG finishing at $42.90 leaves the short in the money and the long worthless. You are assigned on one leg only, so on Monday you are short 100 shares at $42 with a long call that expired. That is the messiest ending this structure has, and it is the same mechanism as on a single option, doubled.
Sizing by contract count. Ten of these is $1,620 of risk, not ten small trades. The maximum loss is genuinely reachable at 14.9 percent per trade, which would imply about a 72.5% chance of at least one maximum loss over eight independent, identical trials. Real cycles need not be independent or share the same probability.
Picking the width
Wider strikes mean more credit and more risk, and the ratio moves.
| Spread | Credit | Max loss | Return on risk | Odds of max loss |
|---|---|---|---|---|
| $42 / $43 | $22 | $78 | 28.2% | 17.2% |
| $42 / $44 | $38 | $162 | 23.5% | 12.6% |
| $41 / $43 | $51 | $149 | 34.2% | 17.2% |
| $43 / $45 | $28 | $172 | 16.3% | 9.0% |
The best-looking return on risk belongs to the $41/$43, which is also the one whose short strike is closest to the money. That is the pattern across the whole table and it is not a coincidence: in this example, the higher return-on-risk figure accompanies a short strike closer to the stock. It does not capture every dimension of risk. There is no width that is free, and choosing by that column alone walks you straight to the most dangerous spread on the chain.
Spreads need a higher options approval level than covered calls or cash-secured puts at most brokers, and they are multi-leg orders: two or four legs to fill on the way in and the same on the way out. Every price here is an illustrative worked example computed off one chain, not a quote.
Check your understanding
You sell a $50 call and buy a $53 call for a net $0.80 credit. With a 100 multiplier, what are the maximum expiration profit, maximum expiration loss, and break-even?
Show the explanation
Maximum profit is $80. The width is $300, so maximum expiration loss is $300 - $80 = $220. Break-even is $50.80. These exclude costs and assume the spread is managed as a complete position; an assigned short leg with an expired long leg can leave stock exposure outside that expiration payoff.
Common questions
What is a credit spread in options?
A short option plus a farther-out protective option of the same type and expiration, with a net opening credit. Maximum intact-spread expiration loss is strike width x multiplier minus credit, before costs; management must address any resulting stock exposure.
How much does the long leg of a credit spread cost?
The example buys the wing for $35, using 47.9% of the short call's $73 credit. That price reduces premium while changing the tail payoff; it is not proof the protection is exactly fair or a bargain.
Is a credit spread better than a covered call?
It needs $162 instead of $3,840 and caps the worst case at a known number. It also pays fewer absolute dollars, $38 against $49, gives you no shares, no dividends and no upside, and the high percentage return is an artifact of the small denominator.
Can I be assigned early on a credit spread?
Yes, on an American-style short leg. A call assignment creates short stock and a put assignment creates long stock. The remaining protective option needs management and does not automatically exercise in response.
Sources
Rules and thresholds above were checked against these documents on August 4, 2026. Exchange and broker rules change. Confirm anything you are about to act on with your own broker.
Keep reading
Do the math on your own trade
Every price in this article is an illustrative worked example, not a quote. Read the Learn hub for the rest of the series, and the disclaimer before you act on any of it. Selling options carries real risk of loss, and the loss can be far larger than the premium you collected.