What Is a Bull Put Spread?
A bull put spread is a defined-risk options strategy that collects a credit upfront and profits when the underlying stays above a specific price level at expiration. It is built with two puts on the same underlying and expiration: sell a put at a higher strike, buy a put at a lower strike. The difference between the premiums is the net credit you keep if both puts expire worthless.
Tradematic is an automated iron condor trading platform that uses bull put spreads on the lower (put) side of every iron condor. Understanding how each component works gives you the full picture of the strategy.
How the Structure Works
Sell a put at a higher strike (the short put) and buy a put at a lower strike (the long put). Both use the same underlying and expiration date. You collect more premium from selling the short put than you pay for the long put — the net result is a credit collected upfront.
Example:
- SPX trading at 5,500
- Sell the 5,300 put for $2.50
- Buy the 5,250 put for $1.00
- Net credit: $1.50 per share = $150 per contract
Profit and Loss Profile
| Scenario at Expiration | Result |
|---|---|
| SPX above 5,300 (short put strike) | Maximum profit: full $150 credit |
| SPX between 5,250 and 5,300 | Partial loss: credit minus intrinsic value of short put |
| SPX at or below 5,250 (long put strike) | Maximum loss: spread width minus credit = $350 |
Maximum profit: $150 (the credit collected) Maximum loss: $350 (spread width of $50 × 100 shares, minus $150 credit) Breakeven: 5,300 − $1.50 = 5,298.50
The maximum loss is fixed. It cannot exceed the spread width minus the credit received, regardless of how far SPX falls.
Why "Bull Put"?
The name describes the directional bias. "Bull" means the trade profits when the market is neutral or rising — it needs to stay above the short put strike. "Put" means the trade uses put options. It does not require an upward move; it just needs the market to avoid falling below the short strike by expiration.
Greeks of a Bull Put Spread
Delta (positive): The spread gains value when the underlying rises, loses when it falls. Delta is near zero when the strikes are far out of the money, and increases as strikes approach the current price.
Theta (positive): Time decay works in your favor. Each day that passes without the underlying reaching the short strike erodes the spread's value toward zero — that erosion is profit for the seller. For a full breakdown of how theta works across options structures, see What Is Theta Decay.
Vega (negative): Rising implied volatility hurts the position. When IV increases, the short put gains value, creating paper losses. When IV decreases after a spike (IV crush), the position benefits. For context on how IV levels affect entry decisions, see What Is Implied Volatility.
When to Use a Bull Put Spread
Favorable conditions:
- Neutral to bullish market outlook
- Elevated IV (more credit available for the same probability level)
- Market near support levels where downside is limited
- 30–45 DTE, where theta decay accelerates
Less favorable conditions:
- Low IV (less credit per spread)
- Strong downtrend or bearish macro environment
- Upcoming binary events with large gap potential (earnings on individual stocks)
Bull Put Spread vs. Naked Put
| Feature | Bull Put Spread | Naked Put |
|---|---|---|
| Maximum loss | Defined (spread width − credit) | Large (stock price − premium) |
| Margin requirement | Lower (defined risk) | Higher (full assignment risk) |
| Credit collected | Less (long put reduces net credit) | More |
| Suitability for automation | Excellent | Requires more capital and active management |
| Risk in sharp drops | Capped at spread width | Can be very large |
The bull put spread gives up some credit to cap the maximum loss — a property that matters most for systematic, automated execution.
From Bull Put Spread to Iron Condor
An iron condor adds a bear call spread on the upside to mirror the bull put spread on the downside:
Bull put spread (put side):
- Sell put at 5,300
- Buy put at 5,250
+ Bear call spread (call side):
- Sell call at 5,700
- Buy call at 5,750
= Iron condor: Profits when SPX stays between 5,300 and 5,700 at expiration.
The bull put spread is the lower half of the iron condor — it defines the floor of the profit zone. To understand the call-side equivalent, see What Is a Bear Call Spread. For the broader structure of how both spread types combine into one trade, see What Is a Credit Spread and What Is an Iron Condor.
The OCC (Options Clearing Corporation) defines the mechanics of options assignment and settlement for all standardized options contracts, including put spreads.
Frequently Asked Questions
What is the maximum profit on a bull put spread? The maximum profit is the net credit received at entry. In the example above, that's $150 per contract. It is achieved when the underlying closes above the short put strike at expiration and both puts expire worthless.
What happens if the underlying falls below the long put strike? Your maximum loss is capped at the spread width minus the credit collected. In the example: ($50 × 100) − $150 = $350 per contract. The long put prevents further losses below that level, regardless of how far the market falls.
When should I close a bull put spread before expiration? Common management approaches:
- Close at 50% profit (buy back the spread for half the original credit)
- Close at 2× credit received as a stop-loss (if original credit was $150, close if the spread costs $300 to buy back)
- Close within 7–14 days of expiration to avoid gamma risk
Can I roll a bull put spread? Yes. Rolling means closing the current spread and opening a new one at a further expiration or different strikes. Rolling out in time can reduce an immediate loss by collecting additional credit, but it also extends the time at risk.
What is the difference between a bull put spread and an iron condor? A bull put spread is one side of an iron condor. An iron condor pairs a bull put spread (put side, lower boundary) with a bear call spread (call side, upper boundary) to create a dual-sided profit zone.
Conclusion
A bull put spread is a defined-risk income strategy with a capped maximum loss, positive theta, and a clear profit condition: the underlying stays above the short put strike. As the lower half of an iron condor, it is the structure that defines the floor of one of the most widely used systematic options strategies.
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Trading involves risk and losses can occur. Past performance does not guarantee future results. Options trading is not suitable for all investors. Only allocate capital you are comfortable risking.
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