After more than 15 years of trading options and running fully automated SPX systems, I can tell you this: most traders don’t lose money because the market moved against them — they lose because they chose the wrong strike prices.
Your strikes determine your probability of profit, your max loss, the credit you receive, and your emotional comfort during the trade. In my Monthly Trend strategy, where I place just one carefully engineered SPX bull put spread per month, the entire edge comes from a disciplined, repeatable strike-selection model.
In this guide, I’ll walk you through exactly how I choose strikes — the same logic behind the Monthly Trend bull put spread signals that have produced strong, steady results for over a decade.
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This episode breaks down the full strike-selection framework discussed in the article, including delta zones, support levels, volatility filters, and how these rules are applied inside the Monthly Trend strategy.
Podcast Transcript: Bull Put Spread Strike Selection — Delta, Support & Volatility
Below is the full transcript of the podcast episode, included for accessibility and for traders who prefer reading over listening. This transcript also highlights the systematic strike-selection logic behind the Monthly Trend SPX bull put spread strategy.
Master the Bull Put Spread: Complete Learning Path
- Step 1: The Foundation: What are Bull Put Spreads? Understanding the core mechanics and risk-defined profile.
- Step 2: Strategy Selection SPX vs. SPY: Which is better for your account?: The tax and liquidity breakdown.
- Step 3: Tactical Execution Strike Selection Masterclass: How to find the sweet spot using Delta and Support.
- Step 4: Defensive Management The Pro Adjustment Guide: How to fix a trade when the market turns against you.
- Step 5: Advanced Setup Advanced SPX Setup & Examples: Real-world application and institutional workflows.
1. Understanding Which Strike Matters Most
Many traders focus on premium first, but that often leads to taking unnecessary risk. The short strike is the true engine of the trade, and choosing it correctly determines whether your spread behaves like a high-probability income trade or a lottery ticket. That’s why every professional I’ve worked with starts with strike logic — not expiration, not credit. A bull put spread consists of two strikes:- The Short Put — your main risk driver (and the strike that truly matters).
- The Long Put — your insurance to cap max loss.
- The probability of profit.
- How far the index can drop and still keep you safe.
- Your stress level during the trade.
2. The Delta Framework: How Pros Think About Strikes
If you asked me to pick just one metric to choose bull put spread strikes for the rest of my life, it would be delta. Delta represents the probability that the option will expire in-the-money. A 0.20 delta put has roughly a 20% chance of expiring in-the-money — which means about an 80% chance of expiring worthless.2.1 My Delta Rules You Can Use Today
- 0.20 Delta (Safer Zone) — Best for income-focused traders or uncertain markets. Roughly 80% chance of the option expiring worthless, more distance from price, less stress.
- 0.50 Delta (Balanced / Directional) — At-the-money area with a 50/50 outcome. You’re expressing a stronger bullish view and accepting more price risk in exchange for higher credit.
- 0.80 Delta (Aggressive / Tactical) — Deep in-the-money territory for puts, with most of the move already priced in. Premium is large, but risk and emotional pressure are higher. I treat this range as a tactical tool only.
- In normal conditions, I tend to build income trades around the 0.50–0.60 delta zone to target a clean 1:1 risk-to-reward at entry.
- In high-volatility or more defensive environments, I may step down into the 0.20–0.30 delta region to buy more distance from price.
- In very specific tactical setups (for example, after a fast selloff or in very short-dated structures), I may temporarily move toward the 0.60–0.80 delta region — but always with smaller size, defined risk and a strict exit plan.
2.2 SPX Example (Realistic)
Let’s assume SPX is trading at 6,800:- 0.20 delta put ≈ 6,700 (further out-of-the-money).
- 0.50 delta put ≈ 6,800 (at-the-money).
- 0.80 delta put ≈ 6,900 (deep in-the-money).
- Short put at 6,860 (slightly above the current price, mid-delta).
- Long put at 6,850 (10 points lower to define risk).
3. Use Support Levels to Reinforce Your Strike Choice
Delta alone gives you probability. Support levels give you structure. Institutional traders — including the teams I worked with early in my career — always check whether their short strike sits below a meaningful support zone. When price falls, these areas tend to act as natural “speed bumps.”3.1 How I Identify Support Quickly
- The most recent swing low (10–20 day range).
- Volume shelf (high-volume area on a volume profile).
- Trendline support during an uptrend.
3.2 My Support Rule
If I’m trading lower-delta structures, I always aim to sell the short strike at least 1–2% below the nearest support level. This gives the trade room to breathe — especially important for SPX, which can drop 50–70 points in a single session without breaking trend.3.3 SPY Example
SPY trades at 500. Support sits around 493. A conservative short strike might be 490 (often close to a lower-delta, safer region). This alignment of delta + support is one reason the Monthly Trend system has had so few losing streaks — only three consecutive losing months since 2013.4. Adjust Your Strikes Based on Volatility (High IV vs. Low IV)
Volatility changes everything. In fact, it influences strike selection more than most traders realize.4.1 When IV Is High
- Premiums expand.
- You can sell further out-of-the-money and still earn strong credit.
- In Monthly Trend, I lean into the 0.20–0.30 delta zone when IV is high, using the richer premium to buy more distance from price.
4.2 When IV Is Low
- Premiums shrink quickly, so far OTM strikes don’t pay enough.
- You’ll usually need to sell somewhat closer to the current price.
- In quiet markets, I may temporarily move closer to the 0.50–0.60 delta region or tighten the spread width to keep the credit meaningful — still with defined risk and controlled sizing.
4.3 My Simple IV Rank Rule
- IVR > 50 → choose safer, further OTM strikes (closer to 0.20–0.30 delta).
- IVR < 20 → expect to move somewhat closer to price (potentially 0.50–0.60 delta, with tighter spreads).
5. How Wide Should the Spread Be?
Your long strike determines max loss and influences your credit. Here’s how I think about width:5.1 Narrow Spread (10–15 SPX points)
- Works well in low-IV environments.
- Reduces max loss per trade.
- Great for smaller accounts.
5.2 Wide Spread (15–30 SPX points)
- Generates more credit.
- Increases maximum loss.
- Better suited to high-IV environments and larger accounts.
6. Full SPX Strike-Selection Example (Real Monthly Trend Logic)
Here’s how I might build a core income trade when SPX trades at 6,800 in a quiet, low-IV bull market:- Check volatility → IVR 16 (low IV).
- Select delta → choose the 0.60 delta region for a 1:1 risk-to-reward profile.
- Map support → recent support sits in the 6,780–6,800 zone.
- Pick short strike → 6,860 (slightly above current price, around 0.60 delta).
- Pick long strike → 6,850 (10 points lower to define risk).
7. Quick Strike-Selection Checklist
Before placing any bull put spread, ask yourself:- Is my short put delta in a sensible range for the current market (for example, 0.50–0.60 for core income trades, 0.20–0.30 when IV is high)?
- Is my short strike aligned with support — or am I trading tactically with a clear plan?
- Is volatility high or low — and did I adjust my strikes accordingly?
- Is the spread width appropriate for my account size and max-loss tolerance?
- Does the credit justify the risk and fit my overall portfolio plan?
- Is the trade structured so I can still sleep at night if price moves against me?