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 helps highlight the systematic strike-selection logic behind the Monthly Trend SPX bull put spread strategy.
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
The Delta Framework: The Most Reliable Way to Choose 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.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.
- 0.50 Delta (Balanced / Directional) — At-the-money area with a 50/50 outcome. You’re expressing a strong bullish view and taking more directional risk.
- 0.80 Delta (Aggressive) — Deep in-the-money territory for puts, with most of the move already priced in. Premium is large, but risk and stress are higher. I treat this range as a tactical tool.
SPX Example (Realistic)
Let’s assume SPX is trading at 6,800:- 0.20 delta put ≈ 6,700
- 0.50 delta put ≈ 6,800 (at-the-money)
- 0.80 delta put ≈ 6,900 (in-the-money)
- High probability of profit
- Short distance from current price (in my base-case 0.50–0.60 structures)
- A $5 credit that makes the trade worthwhile
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.”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
My Support Rule
If you trade lower Delta, always 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.SPY Example
SPY trades at 500 Support at 493 A safe short strike sits at 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.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.When IV Is High
- Premiums expand
- You can sell further OTM 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.
When IV Is Low
- Premiums shrink quickly, so far OTM strikes don’t pay enough
- You’ll usually need to be slightly above 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.
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 0.40–0.60 delta, with tighter spreads)
How Wide Should the Spread Be?
Your long strike determines max loss and influences your credit. Here’s how I think about width:Narrow Spread (10–15 SPX points)
- Better in low-IV environments
- Great for smaller accounts
Wide Spread (15–30 SPX points)
- More Credit
- Higher max loss
- Better in high-IV environments
Full SPX Strike-Selection Example (Real Monthly Trend Logic)
Here’s how I would build a core income trade when SPX trades at 6,800:- Check volatility → IVR 16 (low IV)
- Select delta → choose the 0.60 delta region
- Map support → recent swing above at 6,800
- Pick short strike → 6,860 matches the 0.60 delta area
- Pick long strike → 10 points lower → 6,850
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, lower only when conditions justify it)?
- Is my short strike supported?
- Is volatility high or low — and did I adjust my strikes accordingly?
- Is the spread width appropriate for my account size?
- Does the credit justify the risk?
- Is the trade structured to allow me to sleep at night?