Bull put spread explained: sell a put, buy a lower strike, keep the credit if the stock holds. SPY example with probability, Greeks, and exit rules.
Summary: A bull put spread means selling a put and buying a lower-strike put with the same expiration. You receive a net credit up front and keep all of it if the stock stays above the short strike through expiration. The put you bought caps your loss at the distance between the strikes minus the credit. It's a defined-risk way to collect premium on a stock you expect to stay flat or rise, usually with 30–45 days to expiration and a short strike around delta −0.25 to −0.30.
Last updated: 2026-10-16.
What Is a Bull Put Spread?
A bull put spread is a two-leg options position: you sell a put at a higher strike and buy a put at a lower strike, both on the same underlying and with the same expiration. The put you sell brings in more than the put you buy costs, so you receive a net amount up front. That makes it a credit spread.
The position keeps the full credit if the stock finishes at or above the short strike. It doesn't need the stock to go up — flat is enough, and even a small decline that stays above the short strike is enough. That's the appeal: you're paid for the stock not doing something.
The put you buy is your safety net. Without it, a short put can lose a large amount in a crash. With it, the loss stops at the lower strike. Think of a cash-secured put with the catastrophic tail cut off — in exchange for a smaller credit.
The Trapeze Analogy
A high-wire artist is paid to perform above the crowd. The pay is the credit. Most nights go fine, and the fee is earned. On a bad night, the net below catches the fall — the artist doesn't get paid, and the fall still hurts, but it isn't fatal. The net is the long put: it costs part of the fee, and it defines the worst case.
The analogy has one honest catch. On the wire, a fall is rare. In the market, the stock dropping through your short strike is a normal event that will happen to you regularly. The net isn't a backup plan; it's the reason the strategy is survivable.
Key Facts
- A bull put spread sells one put and buys one lower-strike put with the same expiration; the net credit is the maximum gain.
- Maximum loss = (strike width − credit) × 100: in this example ($10 − $2.65) × 100 = $735 per spread.
- Break-even at expiration = short strike − credit: $740 − $2.65 = $737.35 here.
- The example risks $735 to make $265, with a model probability of about 72% that SPY finishes above break-even.
- Collateral is the strike width × 100 — $1,000 per spread — versus $74,000 for a cash-secured put at the same short strike.
- Theta works for you: at entry the spread earns about $2.65 a day (coincidentally the same figure as the credit) if SPY stays put.
- Rolling a tested spread down and out often costs a net debit; in the example, about $127.
How a Bull Put Spread Is Constructed
The setup has two legs, opened together:
- Sell one put below the current price — this leg collects the premium and carries the obligation.
- Buy one put at a lower strike, same expiration — this leg caps the loss.
The formulas:
Net credit = premium received − premium paidMax gain = net credit × 100 (stock at or above the short strike at expiration)Max loss = (short strike − long strike − net credit) × 100 (stock at or below the long strike)Break-even at expiration = short strike − net creditCollateral = strike width × 100 (the max loss plus the credit you already hold)
Your broker holds the strike width as collateral and gives you the credit, so the cash actually tied up is the maximum loss. See margin and buying power for options for how brokers handle spreads.
Credit spread vs debit spread: the same bullish view, priced two different ways.
Credit Spread vs Debit Spread
A bull put spread is the mirror image of a bull call spread. Both are bullish and both have defined risk, but they work differently:
| Bull put spread (credit) | Bull call spread (debit) |
|---|
| Cash flow at entry | You receive a credit | You pay a debit |
| Comes out ahead when | Stock stays above the short strike (flat is fine) | Stock rises above break-even |
| Time decay | Works for you | Works against you |
| Model probability of profit | Usually above 50% | Usually below 50% |
| Max gain vs max loss | Smaller gain, larger loss | Larger gain, smaller loss |
| Fits best when | Implied volatility is high | Implied volatility is moderate |
The trade-off is the whole story: the credit spread comes out ahead more often but loses more when it loses. Neither is free money; they price the same risk differently.
Bull Put Spread Example: SPY
The SPDR S&P 500 ETF (SPY) traded around $763 in mid-October 2026, according to the SPY quote on StockAnalysis. The example below uses an illustrative scenario with SPY at $760. The numbers are for learning the mechanics, not a recommendation to trade SPY.
SPY has no earnings date, which is one reason credit-spread traders like it. It pays a quarterly dividend, with ex-dividend dates on the third Friday of March, June, September, and December; a 35-day spread opened in mid-October expires before the December date. The example uses an implied volatility of 18%, a 4% interest rate, and SPY's dividend yield of about 1%.
Your view is neutral to mildly bullish: you don't expect SPY to fall more than about 3% over the next five weeks. You open this spread:
| Parameter | Value |
|---|
| Price (illustrative) | $760 |
| Sell | 1 SPY $740 put (delta −0.29) for $7.86 |
| Buy | 1 SPY $730 put (delta −0.21) for $5.21 |
| Days to expiration | 35 |
| Implied volatility (assumed) | 18% |
| Net credit (max gain) | $2.65 per share = $265 per spread |
| Max loss | $7.35 per share = $735 per spread |
| Break-even at expiration | $737.35 (3.0% below $760) |
| Collateral held | $1,000 |
| Risk-to-reward | 2.77 : 1 |
Read the last line carefully. You risk $735 to make $265. That only makes sense because the model gives SPY about a 72% chance of finishing above break-even (a model estimate, not a real-world frequency) — the stock has to fall 3% in five weeks for you to lose anything. Credit spreads trade a high success rate for an unfavorable payout ratio.
{{LIVE_DATA:bull_put_spread:SPY}}
The live widget above shows current SPY data, which will differ from the fixed numbers in this example. Use the example for the logic, then apply the same formulas to live prices.
Bull Put Spread Payoff Diagram
The payoff diagram shows your result at expiration. Above $740, both puts expire worthless and you keep the $265 credit. Between $740 and $730, every $1 SPY falls costs $100. Below $730, the loss is fixed at $735, no matter how far SPY drops.
Bull put spread payoff at expiration: the credit is kept above $740 and the loss is capped at $735 below $730.
| SPY at expiration | Bull put spread P/L | What happens |
|---|
| $800 | +$265 | Both puts expire; you keep the credit |
| $760 (flat) | +$265 | Both puts expire; you keep the credit |
| $740 | +$265 | Short put expires at the money; you keep the credit |
| $737.35 | $0 | Break-even |
| $735 | −$235 | Short put is $5 in the money |
| $730 | −$735 | Maximum loss; the long put starts protecting below here |
| $700 | −$735 | Long put absorbs everything below $730 |
Compare the last row with a cash-secured put at $740: that position would be down about $3,214 at $700 (a $40 drop minus the $7.86 premium, times 100). The spread's loss is capped at $735. That cap is what the $5.21 you paid for the $730 put bought you.
How the Greeks Affect a Bull Put Spread
Because you sold the spread, its Greeks are the reverse of a debit spread's. The table shows the net values per share; the right-hand column translates them into dollars per spread. (Background in the option Greeks explained.)
| Greek | Net spread value (per share) | What it means for you |
|---|
| Delta (Δ) | +0.08 | You gain about $8 per $1 SPY rises and lose about $8 per $1 it falls — mildly bullish |
| Gamma (Γ) | −0.001 | Small and negative: as SPY falls toward $740, your delta grows and losses speed up |
| Theta (Θ) | +0.0265 | Time decay earns you about $2.65 per day at entry, all else equal |
| Vega (ν) | −0.123 | A 1-point rise in implied volatility costs about $12; a 4-point drop earns about $49 by vega alone (about $58 on a full reprice) |
Theta is your income engine, but it starts slowly. If SPY sits at $760, the spread is worth about $2.14 with 21 days left — you're up only $51 — and reaches the 50% target of $1.33 with about 10 days left. Most of the credit is earned in the final two weeks, which is exactly when gamma risk is highest. That tension is the central management problem of credit spreads.
Vega is why the entry rule says to sell when implied volatility is high. If IV drops from 18% to 14% right after entry, the spread is already worth $58 less and you could close early. If IV spikes to 26% in a sell-off, the same spread shows a $74 loss before SPY has even reached your strike. The implied volatility explained article covers how to judge whether IV is high for a given underlying.
When to Use a Bull Put Spread
- You're neutral to mildly bullish. You don't need a rally — you need the stock to stay above a level you choose.
- Implied volatility is elevated. An IV rank above about 50% means today's IV is high compared with its own past-year range, so the credit is richer and more likely to shrink.
- There's support below your short strike. A strike just under a level where buyers have stepped in before gives the trade a cushion.
- You want defined risk with a small capital commitment. $1,000 of collateral instead of $74,000 for the equivalent cash-secured put.
When NOT to Use a Bull Put Spread
- When implied volatility is low. The credit is thin and the risk-to-reward gets worse. At 14% IV, the same spread pays about $2.07 instead of $2.65.
- Right before a known event. Earnings on a single stock, or a major economic release for an index, can gap the price through both strikes overnight.
- When you're strongly bullish. Your gain is capped at the credit. A long call or bull call spread captures a rally; this doesn't.
- When you'd be tempted to hold a losing spread "because it's defined risk." Defined doesn't mean small: the max loss here is nearly three times the credit.
Bull Put Spread Entry Criteria and Exit Rules
When to open a bull put spread and how to manage it.
Entry Criteria: When to Open a Bull Put Spread
- Neutral to bullish view on the underlying.
- IV rank above about 50%: premiums are rich relative to the underlying's own history.
- 30–45 days to expiration: enough premium to collect, with time decay about to accelerate.
- Short strike at delta −0.25 to −0.30, ideally just below a support level.
- Width you can afford to lose: the max loss is the width minus the credit — size the spread by that number, not by the credit.
- Credit at least about one-quarter of the width ($2.65 on a $10 spread is 26.5%); much less and you're risking a lot for very little.
Exit Rules: Managing a Bull Put Spread
- Buy back at 50% of the credit. When the spread can be closed for about $1.33, close it and keep about $132. In the example, that happens with roughly 10 days left if SPY stays at $760. Taking half the credit early avoids the last two weeks, when gamma is highest.
- Close or roll if the short strike is tested. If SPY drops to $740 with 21 days left, the spread costs about $4.30 to close — a loss of about $165. Rolling to a 35-day $725 / $715 spread would bring in about $3.03, so the roll costs a net $127 and moves your strikes $15 lower. Rolling buys room, not a refund.
- Close by 21 days to expiration if neither target nor stop has triggered. With 21 days left and SPY flat, the spread is worth about $2.14; closing keeps about $51. Small, but it avoids the week when a 3–4% move can swing the position from a gain to the maximum loss.
- Close at or near the maximum loss. If SPY is well below $730 as expiration nears, the spread is worth close to its full $10 width. Holding on can't recover anything more — the only thing left to lose is the remaining time value.
- Close both legs together. Closing the long put alone leaves a naked short put with far larger risk.
💡 Pro Tip: In a real brokerage account, a short put can be assigned early when it's deep in the money with almost no time value left. If that happens, you'll own 100 shares and still hold the long put; closing both restores the defined loss. Early assignment is rare while the short strike still has time value, which is one more reason to close tested spreads rather than wait. See what happens at options expiration for how assignment works.
Common Bull Put Spread Mistakes
- Sizing by the credit instead of the loss. Ten spreads look like "$2,650 of income." They're also $7,350 of risk. Size by the second number.
- Selling too close to the money for a bigger credit. A $750 / $740 spread pays more, but the probability of being tested jumps. The delta rule exists for a reason.
- Letting a gain turn into a loss. A spread that's 80% of the way to the maximum gain with a week left is one bad day from a loss. Take the 50%.
- Treating the premium as income. At $265 on $1,000 of collateral, the credit is 26.5% in 35 days. Repeating it every month would compound to an absurd number — if nothing ever went wrong. Something goes wrong roughly three times in ten under the model's own assumptions, and a full loss is almost three credits. Income isn't assured.
- Rolling forever. Rolling a tested spread for a net debit every month means paying to keep a losing thesis alive. If the support level broke, the reason for the trade is gone.
⚠️ Warning: A bull put spread has a high model probability of a small gain and a lower probability of a much larger loss. Over many trades, the losses are expected — the strategy only works if each one is kept to its defined size and the spreads are sized so that a run of losses is survivable.
How to Practice Bull Put Spreads Without Real Money
Pilots practice approaches in a simulator until the checklist is second nature. Credit spreads reward the same discipline: the hard part isn't selling the spread, it's closing it at 50% when every instinct says to wait for the whole credit, and closing it at a loss when the stock reaches your short strike.
In the simulator, you can build the spread straight from the option chain: buy the lower-strike put first, then sell the higher-strike put with the same expiration. Because the long put is already in place, the simulator reserves only the spread width ($1,000 in the example) instead of the $74,000 a lone short put would lock — so the position behaves like a real credit spread. The "Strategies" tab also has a Bull Put Spread template that shows the required capital, maximum profit and loss, break-even, and Greeks before you trade. Run the same trade in the Random scenario several times and count how many paths test your short strike; then try it in the Bull Market scenario to practice taking the 50% early. Each run is a synthetic chart that has never existed, so you're practicing decisions, not memorizing history.
FAQ
What is a bull put spread?
A bull put spread is an options strategy where you sell a put and buy a lower-strike put with the same expiration, receiving a net credit. You keep the full credit if the stock stays at or above the short strike through expiration. The bought put caps your loss at the strike width minus the credit.
How do you calculate the break-even of a bull put spread?
Subtract the net credit from the short strike. In the SPY example, $740 − $2.65 = $737.35. Above that price at expiration, the spread shows a gain, up to the full $265 at or above $740; below it, a loss, up to the full $735 at or below $730.
What is the probability of profit on a bull put spread?
It depends on how far the short strike sits below the price and on implied volatility. A short strike at delta −0.25 to −0.30 typically gives a model probability of profit around 70%, as in the SPY example. The trade-off is that the maximum loss is usually two to three times the credit, so a high success rate is necessary, not a bonus.
When should you close a bull put spread?
Common rules are to buy it back at 50% of the credit, close or roll if the stock reaches the short strike, close by about 21 days to expiration regardless, and close if the loss reaches its maximum. Always close both legs together to avoid a naked short put.
Is a bull put spread better than a cash-secured put?
Neither is better in every case. The cash-secured put collects a larger premium and ends with shares if assigned, which suits a stock you want to own. The bull put spread collects less but caps the loss and needs a fraction of the capital — $1,000 instead of $74,000 in the example — which suits a pure premium-collection view with no wish to own the shares.
Related: Bull Call Spread Strategy, Cash-Secured Put Strategy, Implied Volatility Explained, Option Greeks Explained, Margin and Buying Power.
About the author: Miroslav Slavkovský is the founder of OptionsSimulator and a software developer focused on derivatives-pricing models. He built the platform's simulation engine — implementing Heston, SABR, GARCH, and Monte Carlo methods — so traders can practise options strategies on generated market scenarios rather than on historical charts.
Practice Bull Put Spreads on a Synthetic Chart
Want to find out whether you'd really close at 50% — and really close at the short strike — without risking real money? Open the simulator, buy a lower-strike put and then sell a higher-strike put from the option chain, and manage the spread with the rules above on a synthetic chart that has never existed.
Open Simulator
Frequently asked questions
What is a bull put spread?
A bull put spread is an options strategy where you sell a put and buy a lower-strike put with the same expiration, receiving a net credit. You keep the full credit if the stock stays at or above the short strike through expiration. The bought put caps your loss at the strike width minus the credit.
How do you calculate the break-even of a bull put spread?
Subtract the net credit from the short strike. In the SPY example, $740 − $2.65 = $737.35. Above that price at expiration, the spread shows a gain, up to the full $265 at or above $740; below it, a loss, up to the full $735 at or below $730.
What is the probability of profit on a bull put spread?
It depends on how far the short strike sits below the price and on implied volatility. A short strike at delta −0.25 to −0.30 typically gives a model probability of profit around 70%, as in the SPY example. The trade-off is that the maximum loss is usually two to three times the credit, so a high success rate is necessary, not a bonus.
When should you close a bull put spread?
Common rules are to buy it back at 50% of the credit, close or roll if the stock reaches the short strike, close by about 21 days to expiration regardless, and close if the loss reaches its maximum. Always close both legs together to avoid a naked short put.
Is a bull put spread better than a cash-secured put?
Neither is better in every case. The cash-secured put collects a larger premium and ends with shares if assigned, which suits a stock you want to own. The bull put spread collects less but caps the loss and needs a fraction of the capital — $1,000 instead of $74,000 in the example — which suits a pure premium-collection view with no wish to own the shares.