Vertical Spreads: Why You'd Cap Your Own Upside on Purpose
Buying an option and selling another one against it sounds like undoing your own trade. It isn't — but what you get in return is smaller than the sales pitch, and there's one number that says how much smaller.
By Pavel Penev, MScFounder, TradeWize · 10+ years trading the marketsThe short answer
A vertical spread is two options of the same type and the same expiry date, at two different strike prices — you buy one and sell the other. Selling the second one brings in money, which makes the position cheaper than buying the first one on its own. In exchange, it caps how much you can make. Because both ends are now capped, the most you can gain and the most you can lose always add up to the distance between the two strikes, and nothing you do to the position changes that total.
The first time someone explains a vertical spread, it sounds like a trick question. You buy a call because you think the stock is going up. Then you sell a call — the thing you'd sell if you thought it wasn't. Why would you do both at once?
The answer is that you're not betting against yourself. You're selling off the part of your bet you were least likely to collect on, and using the proceeds to cut the bill. Whether that's a good deal depends entirely on numbers most explainers skip, so we'll do those properly.
We're not going to re-explain what a call or a put is here — our guide to options contracts covers the contract itself, and our piece on the strike price covers how the strike works. Start with those if either is new. What follows assumes only that you know a call lets you buy at a fixed price and a put lets you sell at one.
Two contracts, one position
Say a stock trades at $100 and you think it's heading higher over the next month. You buy the $100 call. You could stop there — and many people do.
Or you could also sell the $105 call, same expiry. Somebody pays you for that one, and their money comes straight off what you just spent. You now hold two contracts, and the thing you own is neither of them individually — it's the sum.
The dashed lines are the two legs on their own: the call you bought climbs away above $100, the call you sold gives it all back above $105. The bold line is their sum, which is what your account actually does — flat, then a climb between the strikes, then flat again.
Look at what happened to the shape. The lone call kept climbing for as long as the stock did. The pair stops climbing at $105 and stays stopped, however far the stock runs. Above that strike, every dollar the call you bought gains is a dollar the call you sold loses, and they cancel exactly.
That flat shelf on the right is the price of admission. You've sold the jackpot to somebody else. What you got for it was a discount, and the discount is the entire point.
Why give away the best outcome?
Because you were probably never going to collect it, and you were paying for it anyway.
A lone bought call has a well-known problem: it needs the stock to move, in your direction, far enough to cover what you paid, before a fixed date. Miss on any of the three and it expires worthless. It doesn't need you to be wrong — being right slowly is enough to lose the whole premium, which is the part our guide to the Greeks spends its time on.
The premium you paid included a charge for every outcome, including the stock going up 40%. If you don't think that's happening in the next month, you're paying for a scenario you don't believe in. Selling the higher strike hands that scenario to somebody who does want it, and refunds you part of your cost.
So the honest framing isn't "capped upside versus unlimited upside". It's: do you want to pay full price for a lottery ticket, or a lower price for the part of it you actually expect to happen? Neither answer is automatically right. But the second one is a real trade, not a compromise.
Credit or debit — and why there are four of these
There are two ways to arrange any pair of strikes, and two contract types to build them from, which is where the four names come from. They sound like four strategies. They're really two shapes, each buildable from calls or from puts.
If you buy the option nearer the money and sell the further one, money leaves your account to open the position. That's a debit spread. If you do it the other way round — sell the near one, buy the far one as cover — money arrives. That's a credit spread.
| Name | You think | Built from | To open | Best case |
|---|---|---|---|---|
| Bull call spread | It goes up | Buy the $100 call, sell the $105 | You pay | Stock finishes at or above $105 |
| Bear call spread | It doesn't go up | Sell the $100 call, buy the $105 | You're paid | Stock finishes at or below $100 |
| Bull put spread | It doesn't go down | Sell the $100 put, buy the $95 | You're paid | Stock finishes at or above $100 |
| Bear put spread | It goes down | Buy the $100 put, sell the $95 | You pay | Stock finishes at or below $95 |
Two of these want the stock up and two want it down, so there's one for every view including "nothing much happens". Credit and debit aren't better or worse than each other — the same position can usually be built either way.
A detail that catches people out: a credit spread is not a position where you've been paid and can now relax. The money in your account at the start is the most you will ever make on the trade. Everything that happens from there can only take some of it away.
Learn it by doing
Reading about it is one thing — it clicks when you do it. Learn it hands-on with free, interactive lessons on TradeWize.
Try the free lesson →The block that never changes size
Here's the piece of arithmetic that makes vertical spreads worth understanding properly, and it's the one thing you should take away if you take away nothing else.
Take that bull call spread — buy the $100 call, sell the $105, and say the pair costs you $2 per share to open, which is $200 for one contract. Your worst case is losing the $2 you paid. Your best case is the stock finishing at $105 or above, where the spread is worth the full $5 gap between the strikes, less the $2 it cost: $3.
Three plus two is five. The distance between the strikes. That isn't a coincidence of the example — it's true of every vertical spread ever opened, at every width, at every price.
Three $100/$105 call spreads. All three are $5 tall because all three have the same strikes. Paying more for one buys a bigger loss and a smaller win — the divider slides, the block doesn't move.
This is why the price you pay matters so much more than it feels like it should. You aren't buying a better or worse version of the trade. You're choosing where to put the line inside a fixed box. Pay less and you keep more of the box as profit, but you're asking the stock to travel further before you see any of it. Pay more and you've bought a nearer breakeven at the cost of most of the reward.
Widening the strikes makes the box itself bigger, which increases both numbers together. There's no setting anywhere on the dial that gives you more upside without handing back exactly as much downside.
The widget below is that box, live. Pick any of the four spreads, drag the strikes apart, drag the price of admission, and watch the bracket on the right-hand side. Its height never changes.
Build a vertical spread
Pick a view, set how far apart the strikes are, and set what the spread costs or pays to open. Watch the bracket on the right: the block never changes height.
Buy the call at the money, sell one further up. You pay to open, and the call you sold pays for part of the one you bought.
Illustrative, and this is expiry day only — commissions, early assignment and everything time value does on the way there are left out. The two sliders move independently, which a real options market would not permit: a wider spread genuinely costs more to buy and pays more to sell, and no market will hand you a credit worth most of the width. Try the comparison the widget exists for. Leave the strikes at $5 wide and drag the premium from one end to the other, watching only the last card. The comforting numbers barely move. The win rate you need travels most of the way across the dial.
What "defined risk" doesn't tell you
Spreads get sold on a genuinely true fact: you know your worst case before you open, and it's a number you chose. Compared with selling an option on its own — where the loss can run a long way past what you collected — that's a real and important difference. It's also the reason a broker will let a smaller account trade spreads at all.
But "you know the worst case" and "the worst case is acceptable" are different claims, and the pitch tends to slide from the first into the second. Defined risk is not small risk. On a credit spread, the defined risk is usually several times the money you collected.
So do the arithmetic the pitch skips. Sell a $5-wide credit spread and collect $1. You make $1 when it works and lose $4 when it doesn't. For that to break even over many repetitions, it has to work four times out of five.
On a $5-wide credit spread, collecting $1 of the width means being right 80% of the time just to break even. Collect $0.50 and it's 90%. The comfortable-looking trades are the ones demanding near-perfect accuracy.
That curve is the honest counterweight to the marketing. High-probability spreads really do win most of the time — that's what makes them pleasant to hold and easy to keep doing. The losses are simply much larger than the wins, arriving rarely enough that a long green streak tells you almost nothing about whether the position was ever profitable.
None of which makes credit spreads bad. It makes the win rate a useless way to judge them. The only question worth asking is whether the market is paying you more than the odds justify, and that's a genuinely hard question that no diagram in this article can answer for you.
Four practical things the diagrams leave out
Every payoff picture in this piece, including ours, shows expiry day. Real positions live in the days before it, where several things happen that the diagram cannot show.
- You rarely hold to expiry. Most spreads are closed early, at whatever the two legs are worth that day — which is usually well short of the maximum. The flat shelf on the diagram is reached at expiry, not the moment the stock crosses your strike.
- The option you sold can be exercised early. American-style options can be assigned before expiry, most commonly on a short call just before a dividend. Your loss is still capped by the leg you bought, but you can wake up holding a stock position and a margin call you didn't plan for.
- You pay the bid-ask spread twice — once on each leg, and again to close. On a narrow spread that friction is a real fraction of the whole trade, which is why liquidity and open interest matter more here than on a single option.
- Both legs must have the same expiry to be a vertical. Same type, same expiry, different strikes. Change the expiry instead and you have a calendar spread, which behaves differently and isn't what this article describes.
How to read one without fooling yourself
- Find the width. Subtract the lower strike from the higher one. That's the total money in play, and everything else is a split of it.
- Find what it costs or pays to open. One number, net of both legs.
- The two caps fall straight out. On a debit spread you risk what you paid and can make the rest of the width; on a credit spread you keep what you collected and risk the rest.
- Work out the win rate you need: your maximum loss divided by the two caps added together. If that number is uncomfortable, the trade is uncomfortable, whatever the probability screen says.
- Check the breakeven against where the stock actually is. It always sits between the strikes, and it's the price the stock has to reach for any of this to matter.
- Then ask the only question that counts: is the market paying you enough for those odds? If you can't answer it, you're not judging the trade — you're admiring the shape of it.
The one-line version
A vertical spread cuts your cost by selling off the outcome you were least likely to see. What you can win and what you can lose always add up to the gap between the strikes, so the price you pay decides how that fixed block gets split — and the win rate you need falls straight out of the split.
What is a vertical spread?
A vertical spread is a position made of two options of the same type (both calls or both puts) with the same expiry date but different strike prices — you buy one and sell the other. Selling the second option brings in money, lowering the cost, and in exchange it caps the maximum profit. It's called vertical because the strikes sit above one another on an options chain.
What is a vertical call spread?
A vertical call spread is one built from two calls. Buy the lower strike and sell the higher one and you have a bull call spread, which costs money to open and profits if the stock rises. Sell the lower and buy the higher and you have a bear call spread, which pays you to open and profits if the stock fails to rise. Same two contracts, opposite sides.
What is the difference between a credit spread and a debit spread?
Which way the money moves when you open it. A debit spread costs money up front: your maximum loss is what you paid, and your maximum profit is the strike width minus that. A credit spread pays you up front: your maximum profit is what you collected, and your maximum loss is the strike width minus that. Both are capped at both ends.
What is the maximum loss on a vertical spread?
On a debit spread it's what you paid to open. On a credit spread it's the distance between the strikes minus what you collected. Either way it's known before you open and it cannot get worse, because the option you bought caps the damage from the one you sold. A $5-wide spread collecting $1 risks $4 per share, or $400 for one contract.
Why do maximum profit and maximum loss add up to the strike width?
Because at expiry a vertical spread can only ever be worth something between zero and the gap between the strikes. Whatever portion of that gap you didn't pay for is your profit, and whatever you did pay for is your risk. The two are carved from the same fixed amount, so raising one always lowers the other by the same amount.
Are vertical spreads safer than buying options outright?
They're cheaper and they cap the loss, but they also cap the gain, and the capped loss can still be 100% of what you put in. Compared with selling an option on its own they are genuinely safer, because the leg you bought stops the loss running. Compared with buying one outright, the risk is smaller in dollars but not necessarily smaller as a share of the money committed.
What win rate do I need for a credit spread to break even?
Your maximum loss divided by the sum of your maximum loss and maximum profit. On a $5-wide spread collecting $1, that's 4 divided by 5 — 80%, before commissions. This is why a long run of winning credit spreads proves very little: the strategy is designed to win often and lose big, so the losses arrive rarely and take several wins with them.
Can a vertical spread be assigned early?
Yes. American-style options can be exercised any time before expiry, and the leg you sold is the one at risk — most commonly a short call just before a dividend. Your maximum loss is still capped by the leg you bought, but early assignment can leave you holding a stock position overnight, so it's worth knowing which of your legs is short and why.
Spreads are a build-it-yourself skill
Reading a payoff diagram is the easy half. The hard half is choosing the strikes, pricing the trade, and knowing before you click whether the odds on offer justify the risk you're taking — which you only get good at by doing it repeatedly and being told immediately whether you were right. That's what TradeWize's options track drills. Educational practice, not signals.